review of rammed earth buildings in the uk

Review of rammed earth buildings in the UK

Lessons learned from:

WISE Lecture Theatre at the Centre for Alternative Technologies

Hill Holt Wood Venue Centre

Pines Calyx Conference Centre

Rivergreen Centre

Educational Centre at the Mount Pleasant Ecological Park

CHRISTINA ANTONELLI

Registration Number: 120185540

Supervisor: Dr Lucy Jones

Word Count: 14,994

ARC 6990 Advanced Project

MSc Sustainable Architecture Studies

University of Sheffield

School of Architecture

Sheffield, 02/09/2013

Acknowledgments

I would like to thank all the people that were willing full to be interviewed, to show me around the

buildings and share with me knowledge and observations through their experiences. Without their support

and contribution this research would not be possible.

Dr. Lucy Jones offered me advice and support throughout regarding all possible areas that this research

could lead but also on how to set the final project.

Special thanks to my parents, family and friends who always encourage, support and advise me for the

best.

Abstract

The research that follows examines the modern applications of rammed earth construction method in UK.

Through the careful presentation and examination of five case studies buildings it attempts a demonstration

of the process that has been followed for their successful accomplishment, the knowledge required, the

people involved and the perception of the final outcome from the users. The comparative analysis

concentrates on three main categories of the buildings’ timeline:

- Before the construction

- During the construction

- After the construction

It recognises the values of rammed earth buildings but also illustrates the limitations of the current

construction industry which currently is not ‘in favour’ of this method. Finally, it draws conclusions and

suggestions that indicate how future applications can be encouraged at a public and private level.

Contents

1. Introduction – Objectives 8

2. Literature Review 10

2.1 Earthen Architecture 10

2.2 Rammed Earth 10

2.2.1 Definition 10

2.2.2 Virtues of Rammed Earth Architecture 10

2.3 Earth Construction Codes 13

2.4 Engineering Considerations 14

2.5 Earthen Architecture in UK 14

2.6 Overview 16

3. Methodology 18

3.1 Introduction 18

3.2 Case Studies Selection 18

3.3 Methods 19

4. Data Collection – Case Studies Presentation 23

4.1 WISE Lecture Theatre, CAT 23

4.1.1 Introduction 23

4.1.2 Interview with Pat Borer (09.08.2013) 25

4.2 HHW Venue Centre 31


4.2.2 Interview with Nigel Lowthrop (09.06.2013) 33

4.3 Pines Calyx Conference Centre 39


4.3.2 Interview with Alistair Gould (09.07.2013) 40

4.4 Rivergreen Centre 46


4.4.2 Interview with Peter Candler (19.06.2013) 48

4.5 Educational Centre, MPEP 53


4.5.2 Interview with Tim Stirrup (13.07.2013) 53

5. Data Analysis – Discussion 59

5.1 Introduction 59

5.2 Analysis 59

5.2.1 Before the Construction 59

5.2.2 During the Construction 60

5.2.3 After the Construction 61

5.3 Overview 62

6. Conclusions 64

6.1 Introduction 64

6.2 Key Findings 64

6.3 Evaluating the Methodological Approach 64

6.4 Recommendations 65

6.5 Future Research 65

6.6 Overview 65

7. Bibliography 66

8. Useful Internet Addresses and Links 71

9. Images Sources 72

Appendices 74

A. Participant Information Sheet 74

B. Comparative Table of case studies’ structural characteristics 76

Figures

Fig. 2.1 Earthen Architecture in the UK 15

Fig. 2.2 All the buildings (identified through literature review) with RE/chalk elements, built over the last three

decades in UK 16

Fig. 2.3 List of all the buildings (identified through literature review) with RE/chalk elements, built over the last three

decades in UK (public - private) 17

Fig. 3.1 List of Interviewees 19

Fig. 3.2 List of Data Intended to be collected from interviews 20

Fig. 4.1 WISE Lecture Theatre, CAT – Project Information 23

Fig. 4.2 HHW Centre – Project Information 31

Fig. 4.3 Pines Calyx Conference Centre – Project Information 39

Fig. 4.4 Rivergreen Centre – Project Information 46

Fig. 4.5 Educational Centre, MPEP – Project Information 53

Abbreviations

BRE: Building Research Establishment

BREEAM: Building Research Establishment Environmental Assessment Method

CAT: Centre for Alternative Technology

EBUK: Earth Building in UK

HHW: Hill Holt Wood

KTP: Knowledge Transfer Partnership

MPEP: Mount Pleasant Ecological Park

RE: Rammed Earth

WISE: Wales Institute for Sustainable Education

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1. Introduction - Objectives

Earth is humanity’s most ancient building material and its importance can be depicted in the earthen

architectural heritage found all around the world (Minke 2006; Houben and Guillaud 1994). Over the last few

decades there has been a growing interest in earth building construction as environmentally and

economically beneficial for the sustainable development of today’s and future’s society (Correia et al. 2011;

Calkins 2009; Rael 2009). A significant revival of modern earth buildings can be found in most regions of the

world (Rael 2009; Harris et Borer 1998). However, only in a few countries (New Zealand, Australia, USA,

Zimbabwe, Spain, Germany, France) exist earthen construction related standards; even more the existing

normative documents do not cover the whole range of earth building techniques and in some cases are

applicable only to a limited territory of the above countries (Silva et al. 2013; Pacheco-Torgal and Jalali 2012;

Gomez et al. 2011; Jimenez and Canas Guerrero 2007; Walker et al. 2003).

In UK there are a number of organizations, practitioners and individuals that are involved in the use of

earth for new constructions, organizing and executing training sessions that aim to develop a theoretical and

practical awareness of the related techniques. Additionally, research is being conducted at university level

(Bath, Sheffield, Plymouth), on both the conservation and the use of earth in new buildings (Correia et al.

2011).

RE was recently rated as a BREEAM A+ material, making it the first earth building material that has been

included in the internationally recognized system of assessment of building materials (BRE).

However, the lack of experience and expertise by the mainstream construction industry along with the lack

of specific national regulatory framework are the two main barriers to overcome in order to officially add

earth as a building material for new buildings and certify its safe use (Silva et al. 2013).

“In 2009, was established a national body, Earth Building UK, with an aim to foster the conservation,

understanding and development of building with earth in the United Kingdom. The EBUK brings together

builders, academics, researchers, architects, engineers, conservators and manufacturers to work in areas of

common interest at a national and local level. EBUK has identified a need to survey and quantify earth

building in the UK as one of their key activities” (Correia et al. 2011, p.191).

From all the above it comes up that there is a necessity of knowledge dissemination actions and a prompt

development of a specific normative related to earth buildings if they are to be encouraged as the heart of

future sustainable construction.

This dissertation focuses particularly on buildings with RE elements that have been constructed the last

three decades in UK. More specifically, five case study buildings are examined with the scope to gain a

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deeper understanding of modern RE construction in UK by showing the process of going from a conceptual

idea into a building and its perception by the end users. The aim is:

a) to map out the knowledge that is required for RE buildings to become a reality

b) to identify how this knowledge-power is spread out amongst the involved people in all phases of the

buildings’ timeline

c) to provide proof for future actions that need to be taken for the promotion of RE buildings

The ultimate goal is to demonstrate clearly what is happening at the moment in UK and illustrate

limitations of the current system. It is envisaged that plausible recommendations for further improvement of

this system could be obtained which could lead to enhancing RE buildings as a more approachable and

reasonable option for both public and private sector.

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2. Literature Review

2.1 Earthen Architecture

Earth can be considered as one of the most ancient building materials (Minke 2000). In developed countries

the practice of building with earth has fallen in disuse over the past century, as a consequence of the

technological development and the extensive use of modern building materials-concrete and steel (Silva et

al. 2013).

Twelve main techniques of using earth as a building material can be recognised, from which seven are

commonly used:

- Rammed earth

- Adobe

- Straw-clay

- Wattle-and-daub

- Compressed earth blocks

- Cob

- Direct Shaping

(Silva et al. 2013; Houben and Guillaud 2008)

Building with these techniques requires shaping, filling, moulding, stacking or compacting an earth mix. For

each one it is required a different mix consistency, which is function of the water content. Despite of the

diversity of earth building techniques, nowadays the most widespread are the adobe, rammed earth and

Compressed earth blocks (Silva et al. 2013; Minke 2000).

2.2 Rammed Earth

2.2.1 Definition

Rammed earth

“Rammed earth is a form of unbaked earthen construction used primarily to build walls. Other applications

include floors, roofs and foundations. Recently it has also been used for furniture, garden ornaments and

other features” (Walker et al. 2005, p.2).

RE building involves compacting moist sub-soil between shuttering, or formwork, which is later removed.

Soil mixes for RE vary; however, the mix is different from other earth construction techniques as it contains

less water. Soil mixes generally contain 15% dimensionally stable clay, 35% silt and 50% sand (both coarse

and fine aggregate) (Calkins 2009; Harris and Borer 2005).

1

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“Loose moist soil is placed in layers 100-150mm deep and compacted. Traditionally, manual rammers have

been used for compaction but nowadays pneumatically powered dynamic rammers are commonly used. Once

the soil has been adequately compacted the formwork is removed, often immediately after compaction,

leaving the finished wall to dry out. Walls are typically 300-450mm thick, but this can vary widely according

to design requirements” (Walker et al. 2005, p.2).

RE is a versatile material which can be used equally effectively for curves and arches as well as straight

walls. RE construction has low material cost but is a labour intensive construction method as compared to

other earth building systems (Calkins 2009; Harris and Borer 2005).

Stabilised Rammed Earth

In some cases where the existing sub-soil is not subjected to be suitable for the RE construction it can be

altered with stabilisers to make it appropriate. Stabilisation can be mechanical (e.g., compacting), physical

(e.g., addition of fibers or minerals), or chemical (e.g., cement, lime, or asphalt emulsions)(Adams and

Elizabeth 2010; Standards Australia 2002; SASZ 724:2001 2001; Houben and Guillard 1994).

A stabilisation process is usually associated with benefits stemming from the fact that the durability and

load capacity of the earth can be improved. However, it should not be underestimated that the embodied

energy and the C02 emissions attributed to the stabilised rammed earth construction increase dramatically

(Calkins 2009).

Rammed Chalk

“Rammed chalk construction is a particular type of wall construction using the rammed earth technique

found in some regions of Britain, such as central southern England, where suitable deposits of chalk are

readily available. The method of construction differs little from rammed earth; walls are formed from chalk

rubble rather than from clay-bearing sub-soil. The excavated chalk is broken down into fragments before

ramming” (Walker et al. 2005, pp. 30-31).

2.2.2 Virtues of Rammed Earth Architecture

Environmentally Friendly and Responsive

Low C02 embodied content and low embodied energy: As RE constructions do not require bricks to be

fired or cement manufactured and the materials are minimally processed and associated with minimal

transport, there is a significant reduction of C02 emissions and a relatively low embodied energy.

Recyclable: It is just earth, which means that after the structure’s useful life, the materials can either be

returned to the environment or reused on a new building.

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High thermal mass: Earth buildings perform very well thermally, with the thick walls moderating

temperature extremes and acting as thermal mass for storing and releasing heat gain from sunlight, reducing

the energy requirement for heating.

Low toxicity: Most earth materials are nontoxic and nonpolluting.

Fire-resistance: RE is generally built using only inorganic non-flammable mineral-based materials.

Occasionally natural fibres may be included, but their quantity is unlikely to impair performance in fire

significantly.

Good noise insulation: The typical thick and dense walls of earth constructions promote a quite ambient

inside.

Local: The raw materials for earth construction, primarily soil and sand, are inexpensive, and often can be

found on or near the project site, reducing transport requirements, emissions and pollution (Pacheco-Torgal

and Jalali 2011; Cooke 2010).

Aesthetic

RE walls have a layered appearance and together with the colour and texture create an inherited quality to

the building that other materials do not offer (Kapfinger and Rauch 2011; Walker et al. 2005). The

psychological impact from human’s response to the texture, shape and irregularities of RE architecture is

positive (Weismann and Bryce 2006).

Healthy

Clay minerals present in RE are hygroscopic, absorbing and releasing moisture in response to changes in the

surrounding environment. This characteristic contributes significantly on regulating the internal

environmental conditions and creating a comfortable and healthy interior ambient (Minke 2006; Walker et

al. 2005).

Durability

“In comparison with other forms of earthen construction, such as cob and adobe, rammed earth

construction offers enhanced density (typically 1770 to 2100 kg/m3), compressive strength (1 to 3 N/m2 for

unstabilised rammed earth) and durability” (Walker et al. 2005, p.13).

Autonomous

The earth as a readily available material encourages and allows self built construction. As the material is

easily accessible, the construction is relatively quick and easy. The success of an earth construction though

relies on craft skills and techniques, apprentices and master craftsmen. In places where these skills are

negated and in decline, the earth architecture places value on these skills and intangible heritage. In the

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modern society the autonomous nature of earthen architecture, which enables construction to occur

separate from the global construction industry can be a powerful attribute (Cooke 2010).

Humanity

Earthen architecture can be a community activity that embraces the value of collaboration and respect of

people in a social context. Earth, as a natural, living and ‘breathing’ material creates a feeling of connection

to the people that live in earthen buildings. Symbolic associations between ‘living’ and ‘dead’ materials

impact the perceived appropriateness of the material. In the past, the ‘living’ qualities of earth were

perceived as a ‘vice’ and had a negative impact on the view of earthen architecture. On the opposite, today

those ‘living’ properties are taken on as a ‘virtue’ and contribute to the positive view of the material (Cooke

2010).

Modernity

Architectural modernity can be expressed through the environmental responsiveness and friendliness that

characterize earth building materials. The reflection of environmental concern combined with complex and

dynamically beautiful earth buildings can allow modern construction forms to take place. One such is the

case of modern RE buildings (Cooke 2010).

2.3 Earth Construction Codes

In some countries, where earth has been used extensively in recent years for the construction of new

buildings, technical standards and codes of practice have been adopted and now form the basis of regulatory

or advisory systems for controlling and overseeing earth-wall construction. Countries whose national or in

some cases regional governments have now adopted such standards include Germany, New Zealand,

Australia, Switzerland, France, Spain, Zimbabwe and New Mexico, USA (Pacheco-Torgal and Jalali 2011; Keefe

2005).

At the present there are no British standards regarding the use of earth for building construction (Correia et

al. 2011). ‘Rammed Earth, Design and construction guidelines’, by Walker et al. 2005, is the only existing

book regarding this technique in UK and provides mostly guidance rather than setting a control of regulation.

RE structures can be challenging as the standards do not currently cover those type of constructions and

engineers are not trained to design them; however, the body of research on structural performance of RE is

growing (Calkins 2009).

It is important to always bear in mind that “In setting standards and codes of practice for earth building

there are two key issues that need to be addressed. The first relates to the raw material and how its

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suitability for building construction may best be assessed and the second concerns the need to ensure that the

construction process is carried out to a satisfactory standard by suitably trained and experienced personnel”

(Adams and Elizabeth 2005, p.158).

2.4 Engineering Considerations

RE is certainly not a universal panacea for sustainable building. There are many situations where RE is

entirely suitable, however, its limitations, weaknesses and drawbacks need to be carefully considered during

selection and design. The most significant issues for consideration are the following:

- Durability

- Wall thickness

- Thermal resistance

- Material selection and variability

- In-situ construction

(Walker et al. 2005)

Walker et al. in their well written book ‘Rammed Earth, Design and construction guidelines’ cover all of the

above issues along with certain recommendations/guidelines on how to evaluate soil suitability for a RE

construction. Analytic structural methods and structural details are also presented.

2.5 Earthen Architecture in UK

Earthen architecture in UK is divided in two categories:

- buildings undertaken in historic heritage contexts

- new buildings

“The regional basis established in Terra Britannica remains important. In the South-West, cob

predominates, whilst in the Eastern part of the country clay lump is common. There are numerous other areas

that use earth on a supporting framework (wattle and daub, mud and stud). As in the rest of the world, since

the 18th century, vernacular practices were challenged by so called ‘conventional’ building materials. A

number of modern rammed earth projects in regions with no historical precedence have been undertaken

more recently” (Correia et al. 2011, p.189).

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Fig. 2.1 Earthen Architecture in the UK (Correia et al. 2011)

Earth building is diverse and vibrant, with passionate individuals presenting a consistent and persuasive

argument for the use of earth in conservation and new build projects. EBUK brings together all people

involved in areas of common interest at a national and local level. They range between practitioners, regional

interest groups (Devon Earth Building Association, East Anglia Earth Buildings Group) and universities that

undertake research in relation to conservation and the use of earth in new construction. The BRE Centre for

Innovative Construction Materials, in the Faculty of Engineering and Design at Bath University, has been

active in developing approaches to the use of unfired clay masonry and RE (Walker et al. 2005), which has

been included in the BRE Green Guide to Specification (Correia et al. 2011).

Rowland Keable (Ram-Cast CIC) has been involved in a number of high profile projects using RE across the

UK over the last 20 years and has trained a range of businesses and individuals in the use of RE. He has

worked with this method since 1985, in Africa and Australia, but mainly in UK the last years, and he is

probably the most expert at the moment.

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“National initiatives supported from a variety of different funding sources, such as the heritage building

skills bursary scheme, are intended to address skills within the traditional crafts and built heritage sector. The

current planning requirements for conservation and ecological use of materials in new construction are a

good background for development into the 21st century. A number of high-status projects continue to inspire

the use of earth for artistic and aesthetic reasons, alongside environmental aspirations” (Correia et al. 2011,

p.191).

2.6 Overview

In this tentative context, earth might once more be a material of choice for the mass market rather than

specialist applications. An analysis of existing RE buildings could highlight aspects related to the required

knowledge, technology and construction in UK, aiming to evaluate the current system’s situation and provide

a basis for improvement and further development of that system.

Fig. 2.2 All the buildings (identified through literature review) with RE/chalk elements, built over the last three decades

in UK

Name Location Built Year

Use Type of Rammed earth elements

1 Arch building Cornwall 2012 Barn The building stand on a rammed earth plinth making the floor level with the ground sloping down to the existing barn

2 Ecobarn, King Edward VI Academy Spilsby, Lincolnshire 2011 Classrooms Rammed Earth Wall

3 Classroom Block , Netherfield Centre for Sustainable Food and Farming

East Sussex 2011 Classrooms Load bearing rammed earth walls

4 WISE lecture theatre, CAT Machynlleth, Wales 2010 Lecture Theatre Rammed Earth Walls

5 Othona Bradwell on Sea, Essex 2010 Community Meeting Space Rammed Earth walls

6 Lecture theatre Hill Holt Wood, Lincolnshire 2008 Lecture theatre Rammed Earth walls

7 CHP Boiler House Brent, London 2008 Heat and power plant Rammed Earth walls

8 Wahaca Restaurant Covent Garden, London 2007 Restaurant Rammed Earth walls

9 Ivylands classroom Battle, Sussex 2007 Classroom Rammed Earth walls

10 Pines Calyx conference centre White Cliffs, Dover 2006 Conference/Events venue Rammed Chalk main walls

11 Genesis Project Somerset 2006 Sustainability Center Rammed Earth Pavilion walls

12 Boiler House Eglwysfach, Wales 2005 Boiler house Rammed Earth walls

13 Rivergreen Centre Aykely Heads, Durham 2005 Offices building Rammed earth spine wall

14 Garage Danbury, Essex 2004 Garage Rammed Earth walls

15 Mount Pleasant Ecological Park

Porthtown, Cornwall 2003 Educational Space Load Bearing Rammed Earth walls-Rammed Earth Floor

16 Sheepdrove Organic Farm Lambourn, Berkshire 2003 Education /Conference Centre Rammed Chalk, non-loadbearing internal wall

17 Private house Manaccan, Cornwall 2002 Residence Rammed earth plinth walls

18 The Stables Ashley, Northamptonshire 2001 Stables Cement stabilised rammed earth; load bearing external and Internal walls

19 Jasmine Cottage Blakeney, Norfolk 2001 Residential property Cement stabilised rammed earth; load bearing external and internal walls

20 Big Brother Den London 2001 TV Show House Rammed Earth walls

21 AtEIC Building, CAT Machynlleth, Powys 2000 Visitors Centre Rammed earth, loadbearing internal walls and columns

22 Visitors Centre, Eden Project St Austell, Cornwall 1999 Public visitors Centre Rrammed earth; non-load bearing internal walls

23 Woodley Park Centre for Sports and Arts

Skelmersdale, Lancashire 1999 Sports hall Cement stabilised and natural rammed earth; non-load bearing External walls

24 Dragons Retreat (formerly known as West Lake Brake)

Plymouth, Devon 1997 Residential Cement stabilised rammed earth; load bearing internal and non-load bearing external walls

25 Holy Howe Warburg Nature Reserve, Oxforshire

1992 Fruit/Vegetable Store Cement stabilised and natural load bearing rammed earth; external and internal walls

Fig. 2.3 List of all the buildings (identified through literature review) with RE/chalk elements, built over the last three decades in UK (public - private)

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3. Methodology

3.1 Introduction

As previously discussed, on the one side, there is a general perception that the lack of experienced

engineers, skilled craftsmanship, code officials and contractors, the absence of earth related courses and

regulations and most of all the fact that earth construction is usually associated with low income status may

currently be the largest obstacle to earth buildings in many areas around the world.

However, on the other end of the spectrum, a significant number of new RE/chalk buildings built over the

last three decades can be found in UK. Yet, the number of these buildings comparing it to the total number

of buildings in UK can be considered as negligible, but it signs that society is brought on a way of re-

examining the values of earth as an essential material for use in the architecture of tomorrow.

In that context a careful investigation of these buildings would reveal key issues that came up during the

whole process of their completion. A critical evaluation of the various aspects that have been taken into

consideration from all the parts involved into these projects could identify possible similarities or differences

regarding the process that has been followed for each project. Thus, by comparing and synthesising all the

gathered information there is an attempt to give an outline of valuable lessons learned out from the stories

of these buildings.

3.2 Case Studies Selection

Even though an examination of all the buildings would give more informed conclusions, for the purposes of

this dissertation and considering the limited time duration, it was decided that five buildings would be

selected as case study buildings:

- WISE Lecture Theatre, CAT, 2010

- Hill Holt Wood Venue Centre, 2008

- Pines Calyx Conference Centre, 2006

- Rivergreen Centre, 2005

- Educational Centre, MPEP, 2003

The buildings were selected according to the following criteria:

- They are public/semi-public buildings, which also made them more accessible than private ones.

- They are big scale projects.

- They are spread out in the whole territory of UK covering different local climatic conditions and soil

properties.

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- They cover all of the possible categories of RE/chalk wall elements:

- Load bearing RE wall (straight and curved)

- Non load bearing RE wall (straight)

- Load bearing rammed chalk wall (curved)

- Non load bearing rammed chalk wall (curved)

3.3 Methods

The presentation and analysis of the case studies synthesises information and qualitative data that have

been collected through the existing literature review, but mainly through interviews. Useful information

and visual material has also been extracted from the website of Ram Cast-CIC, as an interview with

Rowland Keable (involved in various ways in all the examined buildings) was not possible to be scheduled.

For each one of the five case study buildings one person was interviewed. The interviwees were in charge

for the whole process of the building starting from the conception of its idea upon the completion of its

construction. Architects, contractors and engineers usually do not come back to the buildings after they

complete their tasks. However, the people interviewed are frequent or daily users of the buildings and

interact with external visitors and users. Thus they had the critical ability to provide valuable information and

feedback regarding:

- The perception of the building from the users’ point of view and their attitude towards the examined

buildings.

- The life of the building after its construction and possible practical issues that come up on a daily basis

during the operation of the building, related directly to the earth elements but also from a holistic

perspective.

Case Study Building Name Status

WISE Lecture Theatre at CAT Pat Borer Architect

HHW Venue Centre Nigel Lowthrop Business Founder/Director

Pines Calyx Conference Centre Alistair Gould Chairman of Bay Trust

Rivergreen Centre Peter Candler Project Manager

Educational Centre at MPEP Tim Stirrup Business Founder/Director

Fig. 3.1 List of Interviewees

The interviews were semi structured, that is to say the interviewees were not asked to strictly answer

certain questions rather to talk about specific topics. It was a deliberate decision to take interviews in that

way instead of asking them to fill out questionnaires, in order to give them the opportunity to tackle and

analyse unexpected themes that came up during the discussions with them. Besides, in that way they were

inspired to add useful information according to their judgement and also discuss the arising matters inside

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the building while they were showing me around. It is worth mentioning that the knowledge gained from the

interviews would not have been the same if they had not taken place during the field visits. All the interviews

were recorded and transcribed into text form in order to allow for a thematic analysis to be done.

The topics that were asked to be analysed from the interviewees included three different categories of

data:

- Objective

- Subjective

- Empirical

Objective Data

1. Design and construction process followed

2. Quality Control – Soil testing procedures followed for assessing suitability

for use

3. Special difficulties or limitations faced through the construction -

Ways of facing or adapting to them

4. Planning permission requirement

5. Special architectural details required in connection with other materials

used - Maintenance and repair issues

6. RE building team – Experience and training required

7. Overall energy performance – Monitoring results

8. Financial aspects of the project

Subjective Data

1. Motivation/Inspiration for deciding to include RE/chalk in

the design

2. Awareness of precedent RE/chalk projects

3. Project as a challenge or not

4. Comparison between Initial perceived design and final outcome- Pleased

or dissatisfied by this

5. Actions that would have been done differently after its

completion – Decisions that would have been taken differently –Lessons

Learned

Empirical Data

1. Energy performance as perceived by users

2. Feedback for users’/visitors’ experience from the interaction with them

3. At which extend users/visitors consider it

pleasant/motivational/attractive/stimulant environment compared to a

conventional environment

4. Suitable building technique for private or housing projects

5. Interest from the users-/visitors to adopt it

Fig. 3.2 List of Data Intended to be collected from interviews

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The collected information and data have been thematically analysed and the results of this analysis are

presented in Chapter 5.

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4.1.0.1 WISE Building Plan

4.1.0.2 WISE Building Axonometric

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4. Data Collection – Case Studies Presentation

4.1 WISE Lecture Theatre, CAT

Location CAT, Llwyngwern Quarry, Pantperthog, Machynlleth,Powys,

SY20 9AZ

Date 2010

Client CAT

Architectural Design Pat Borer and David Lea with Alison Jardine

Structural and Civil

Engineering

Buro Happold

Earth Wall Consultants Ram Cast - CIC

Rowland Keable

University of Bath, Department of Architecture and Civil

Engineering

Pete Walker

Contractor/Developer Initial contractor: Frank Galliers

Completion contractor: Ian Sneade

Awards RIBA Award 2011

Triennal Dewi-Prys Thomas Prize for a ‘fantastic creation’

Top Building 2010, Daily Telegraphy

Favourite completed building of 2012, Architects Journal

Fig. 4.1 WISE Lecture Theatre, CAT – Project Information

4.1.1 Introduction

WISE lecture theatre is part of the wider building complex of the Institute. The whole building is designed

to require minimal heating and lighting, using passive ventilation, solar gain, daylighting, thermal mass and

high levels of insulation. The 200-seat lecture theatre is a 7.2m high; 15m diameter drum of load bearing RE

walls surrounded by hemp lime external walls with a high glazed sunspace on south and is being ventilated

via a ground source heat exchanger. On the roof there is a central oculus with a swinging panel which can

control daylight in the building according to activity needs. A 7.2m high sliding door on the south side

functions supporting to bring in natural light and heat the earth walls.

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4.1.2 Interview with Pat Borer (09.08.2013)

In CAT the first RE building that had been constructed was the Visitors Centre in 2000. In making that

building a reality they spent money in order to do the proper research and find the right earth mix. From that

process, Pat and the client gained the knowledge and confidence that earth is a beautiful, strong and dense

material that can be used for structural load and act as thermal mass in the building. Additionally, the

architects were aware of Martin Raush’s work and had already visited the chapel of Reconciliation in Berlin

which is about the same size as the lecture theatre. Thus, when it came to the theatre they already knew

what can be done with earth. The decision for a circular lecture theatre came from the client and then

together with the architects and engineers they agreed on using earth as it was successful in their former

building and they wanted it to be a special space.

Pat claimed that while they were designing the building they thought of different ways of constructing the

earth wall. They could have constructed it in free standing panels as they did in the visitors centre or cast it in

one big mass with holes for the openings as in the chapel of reconciliation. However, at the end they decided

to make it in four sections. In taking that decision Rowland, who consulted them, played an important role as

he was very keen to use a commercial square-dimensioned shuttering for concrete which is made out of

steel frame with bent plywood. As Pat referred “It was a long process between Rowland, the structural

engineers, ourselves (designers) and the contractor to arrive at what solution we wanted”.

The site stands on a slate area with no earth available at all. The soil used for the earth wall, almost

320tonnes, was sourced from a local quarry around 60km away. They looked at different quarries but at the

end it was supplied from the same quarry used for the visitors centre because it has been tested and judged

as of good quality. Pat claimed that the rain is a big problem while building in Wales and therefore they were

bringing each time enough soil to be stored on site locally for immediate use. It was extremely important the

fact that they could sheave the soil and bring it quite dry as it was straight out of the ground.

They collaborated with Pete Walker and tested different samples of different places (SIV analysis), but the

one they used turned out to be a good mix and they did not have to add anything. As Pat said “It would be

stronger if it had bigger gravel pieces in it, but we liked the very fine appearance of it and the sense that

traps”.

The engineers advised on the thickness of the wall which it needed to be 500mm because of the decision to

build the wall in four curved sections. They built the foundations wider to allow an earth wall of 600mm

thickness, in the case of the wall done in more sections. If it was a complete curve it would have come to

about 400mm thick.

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- 27 -

During the whole construction process the contractors were required to test the moisture content of

rammed samples every day. The second requirement was to send occasionally a representative sample to

Pete for testing.

Two big segments of one of the four sections had to be taken down and be rebuilt again, because when

they took the shuttering off, the top started collapsing. As Pat explained “the representative samples that

were sending to Pete were not always actually representative, as they rammed the samples differently than

they actually rammed the walls”. Rowland was employed from the contractors as an advisor but also to train

the construction team on the RE technique. However, the “big mistake” that was made from the part of the

contractors is that they did not use the trained set of people, but they got other people, perhaps “cheaper

enough”, according to Pat. “They had not been trained in a way that Rowland had taught them, so these

people were taking shortcuts”. Pat characteristically said “They have not followed the specification which was

very specific. It had to be 100mm compacted to 50mm. If you see in the wall every layer is 50mm but when

we measured it after that bit collapsed up there and we took some more shutters off it was about 80mm. So,

either they had not compressed it or they have taken a much thicker layer. So they made a big fast saying

that it was not their fault, but it was. There is no doubt. You just have to take measures”.

Pat admitted that in the end they did it properly because this mistake cost the contractor so much that

then the construction team was very careful to make sure that every layer had the right depth and was well

compacted. The shuttering used was hired by the contractor at a cost of about 250£/week. A team of about

6 people worked for a year in order to construct the earth walls. They shuttering used was enough for two

segments of every section. Thus, they usually had two people on the ground mixing the earth to achieve the

right consistency, putting it in the lift, taking up to the scaffolding and distributing around. A team of two

people were ramming and the last team was responsible for lifting the shuttering on and off. The main

reasons that took them so long to complete it were:

a) The delays from having to stop because it was raining quite often

b) The delay of the whole section which had to be redone

c) The fact that they did not have enough shuttering

Pat mentioned that they were very keen to put up a temporary roof as they had done in the visitors centre,

in order to avoid the delays and frustration because of the weather. Besides he was of the opinion that they

should have made their own shuttering out of timber and plywood to speed up the construction and reduce

the cost. Furthermore, the internal part of the wall had a different radius from the external part of the wall.

Because of this, at the external part they had to add an extra piece of timber between the two pieces of

shuttering to cover the missing part. Pat said that they could adjust that difference by making and using their

- 28 -

own shuttering. However, the contractor claimed that these options were not affordable. Discussing the total

cost of the earth wall, Pat emphasized that at the end “We don’t know how much it cost unfortunately

because the contractors are putting a price and that is what we paid for. But we know that it cost them

considerably more. Mostly it was not the earth that cost the money, it was the shuttering”.

He continued characteristically that “There are lots of annoying bits of work they did that you probably

can’t see, but I can”. He mentioned that at some parts the shuttering was not entirely parallel which resulted

in an increasing thickness of the wall across its height. Taking it as a whole it does not matter at all but that

raised some difficulties because when it came to make the ring beam on top, the wall was not exactly

circular.

One of the positive aspects that Pat recognised is that the contractor decided to search and find different

pneumatic rammers than the ones that Rowland was using as they could only be used for 30 minutes,

because of health specifications. He found another supplier who provided pneumatic rammers that they had

the standards to be used for half a day.

According to Pat the advantage of not having a roof before they constructed the earth wall is that “they

could use this very heavy shuttering and when they took it off they could jerk it upwards. So, it slit against the

earth and left a quite clean finish”.

As the wall is internal there was no need for a surface coating. However, in the interior of the lecture

theatre they sprayed the wall with sodium silicon up to a height of about two meters. It was the client’s

decision so as to avoid people to rub off the wall. The timber wainscot inside the lecture theatre acts as part

of the sound absorber system, as it was acoustically tested for a reverberation and they had to reduce the

levels. In fact the results showed that they had to round further the timber with sheep’s wool insulation but

they preferred to leave a part of the earth wall exposed. Pat explained that “If you use the earth wall as

internal wall then you get both sides for the thermal mass and you see it from both sides. The outside in this

case becomes a solar collector from the south side which is glazed and it can pick up some heat. So we think it

is a more sensible way to use it as an internal – load bearing partition in a way”.

The holes that are visible through the wall were from the bolts that used to hold the shuttering together.

They decided to leave those instead of filling them as it usually happens in RE buildings. They actually did fill

a few that were not in nice positions but left the most of them to let a little bit of light coming through but

also because it shows the way it was made.

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The roof of the lecture theatre is self supporting but it is spreading out the load to the earth wall. The load

is spread out through fifteen triangular timber trusses. Pat explained that “there is a system of wedges under

the trusses in case for shrinkage. Because as the wall shrinks the building would drop and it might not drop

even. But in fact the shrinkage was tiny, 15mm in the height of the wall, which is nothing really. By the time

they finished the roof the wall was dry enough to not shrink anymore. So we never used these at all”.

Throughout the whole life of the building so far there has not been detected any sign of settling or crackling

from the heavy weight on the wall.

Within the earth wall there are monitors installed and they have got data but as far as Pat is concerned

there has not been done any analysis yet. Peter confirmed that the temperature and humidity levels inside

the building are comfortable. He explained that when it gets hot the ventilation system is used during the

night with the aim to cool the earth mass down and it is very efficient. However there are some times when

it is quite chilly because the radiant heat is low. This has to do with the fact that the lecture theatre is used

intermediately, that is to say heavily use on weekends and then not at all for a week, which allows dropping

down its temperature. The heating system they use is underfloor heating but mainly a ventilation heat

recovery system which has a heater battery to pre warm the air. It is treated by carbon dioxide sensors that

trigger the system to switch on and off according to the number of occupants. That system is really efficient

and has been successful in the building.

In terms of visitors’ attitude towards the building Pat said that they always find it a lovely space to be and

describe it as ‘powerful’ and ‘extraordinary’. The beauty of the earth and the reverberation make people feel

like they are in “a circular cathedral, a church but not religious one” and they keep quite. It gives an

atmosphere that other materials do not, probably because people have grown up being surrounded by earth

and wood for centuries.

Pat concluded that the stimulus for this project was to demonstrate that “in a modern building, a prize

winning building, you can use the most basic, simplest and lowest impact of building materials that is

available around, and has been used throughout the world, in a quite sophisticated way to make something

that is prestigious and relatively famous in architectural terms”. He added that “sticking with very simple

palette of materials is the sort of architecture that we like because it is sort of honest, as it can be” and he

explained their intention to use simple materials as monolithic earth and solid softwood, and where possible

assemble things rather than glue everything together, to allow their reuse after the completion of this

buildings’ life.

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4.2.0.1 HHW Model

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4.2 HHW Venue Centre

Location Hill Holt Wood, Norton Disney, Lincolnshire, LN6 9JP

Date 2008

Client Hill Holt Wood Environmental Social Enterprise

Architectural Design KTP Academic Partner

University of Lincoln, School of Art, Architecture and Design

Behzad Sodagar

KTP Associate

Bryce Gilroy-Scott

Simons Design Limited


Engineering

KTP Academic Partner

University of Lincoln, School of Art, Architecture and Design

John Chilton


Rowland Keable


Engineering

Pete Walker

Contractor/Developer The fund budget was managed internally by HHW project

managers as a self build project arranging individual contracts with

all trade contractors

Awards Green Apple Award Housing Associations

Green Apple Award for the Built Environment

Green Apple Champion Award 2009

Green Apple Champion of Champions Award 2009

Lord Stafford Award for Innovation for Sustainability 2009

Knowledge Transfer Partnership Award for Best Application of

Social

or Management Science

Fig. 4.2 HHW Centre – Project Information

4.2.1 Introduction

HHW is a social enterprise in a 34 acres woodland and is active on training disaffected young people on the

principles of woodland management. In 2005 they entered into a Knowledge Transfer Partnership (KTP) with

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the scope to establish a sustainable construction company to enable HHW to provide also training in

ecological building techniques and skills. In that context they designed a small low carbon Woodland

Community Building, part of each is the venue centre. The venue centre is a dodecahedron in plan with three

of the RE walls being totally internal on the eastern part. It is a space that can accommodate maximum 100

people and is being used for conferences and all sorts of events.

4.2.2 Interview with Nigel Lowthrop (09.06.2013)

HHW had a plan for a community building on site which would operate for various purposes, i.e.

conferences, events, workshops etc. They first developed an idea for a building made out of timber at a cost

of 50,000£. The main concept was a structurally integrated panel system with removable walls. They wanted

to take advantage of the proximity with the woods and design a building that can be opened to the nature

and provide sitting space with views over it.

They developed a relationship with the University of Lincoln and set the students within the second year

undergraduate studio a challenge to design a building using natural materials. They came up with the idea of

a three section building (the communal space, the conference room, the dining area with kitchens and

offices above) and actually this idea reflected their aim which was a fairly open building from which people

could look out into the wood.

After that they gained a KTP with Lincoln, financed by the Department of Trade and Industry, and they

appointed as their KTP associate, Bryce Gilroy-Scott, who was “the most motivated and at that time was

completing his masters in Sustainable Architecture at CAT”, according to Nigel. The students’ design was

further developed by the HHW in conjunction with all the architects involved.

One of the pivotal principles they wanted to implement into the project was “to be as low impact as

possible, built out of either recycled materials or locally sourced materials”. In fact, all the former buildings on

site reflected this approach (straw bale buildings) and Nigel himself was already aware of the RE visitors’

centre at CAT. Though, in the decision making process played role other factors as well. The final decision

was a balance between sustainability, practical and flexible use, cost and longevity of the building. Nigel

noticed characteristically that “Bryce was always trying to do everything super green and although I

absolutely agree with him, I aspired the building to be as low impact and as green as possible, if by a 10%

increase in your carbon footprint you extend the life of the building from 50 to 500 years, then that is what

we are doing here”.

In order to assess the suitability of the existing soil on site they collaborated with Pete Walker. They sent

blocs of the soil and did compression tests. They found out that the soil had different properties for every

trial pit they dug. Thus, they only had to mix the existing soil in order to get the right aggregates proportion.

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In total they mixed 250tones of soil that was dug from the pond right next from the building. They did not do

any humidity tests in the lab and as Nigel said “I remember the engineers complaining about that”. He

continued on by explaining that they were doing the drop off test on site which they found to be very

accurate.

Rowland assisted on the design work but particularly trained a team of around seven young unemployed

people, excluded from school, which were given the chance to learn and work on that. The training session

last one week and as Nigel explained “the key thing is putting the shuttering up and making sure that it is

straight, which obviously is quite tricky with a shape like that”. They used steel shuttering to form the walls

which have been curved from the inside and facetted from the outside part, changing in thickness between

350mm and 500mm. They build it in vertical sections, leaving in between gaps which were completed on a

second phase. According to Rowland’s predictions they would be able to complete the building in three

weeks, but Nigel confirmed that the construction process was quite slower and at the end it took them 3-4

months.

One of the reasons for that delay was the fact that they faced a problem with a section of the wall. One of

the layers, at around one third on the way up, had not been vibrated enough which resulted in the fall of the

wall when they took the shuttering off and thus, they had to rebuilt it again. This was a lesson for the

construction team which was really careful after that.

Nigel mentioned that if it was possible they would have enough shuttering to do the whole building in a go,

instead of building it in sections and reusing the shuttering. However, that option was expensive. He

admitted that he “should have been involved more in the whole process rather than leave the architect and

the University involved to solve most of those issues”. One additional thing he would consider doing

alternatively is “the use of wooden boxes that act as shuttering for shaping the openings of the building, but

are permanent and are left inside the wall after the ramming process”. This might involves some difficulties

as these “boxes” should be designed from very strong wood and they should be strengthened in a way that

they would not flex or be affected under the weight of the wall. On the other hand, some advantages come

along with this process as it would ease the fitting of windows and doors and would also take away some of

the “risk points”. By “risk points” Nigel was referring to all the corners of the earth wall which are more prone

to be damaged from chairs or users of the building. With the system of the “boxes” the edges of the earth

could be protected without having to add extra protection stripes which visually might not be the best

option.

On all the parts of the wall that are internal there has only been applied sodium silicon, in order to stop the

dust coming off. There was a discussion on whether or not they wanted to get a really smooth finish, as in

the Ateic building in CAT, but at the end they decided to leave it as it was. As Nigel pointed “if you look

- 36 -

around the wall, apart from gravel, occasionally you see some nails and all sorts of weird things”, which had

accidentally been dropped into the earth while the shuttering was been taken off. In fact, Nigel finds this as

positive and as he said they could have actually planned to throw i.e. pieces of glass to be embedded in the

wall and get an interesting colorful outcome.

The external parts of the wall have been insulated and lime rendered, but in that way the south facing walls

can’t store heat gains. Nigel claimed that there are plans for a retrofit proposal which includes removing the

insulation, exposing the RE wall and adding a glass conservatory and solar roof from the outside, with the

aim to allow the wall to act as thermal mass during the winter, but also extend the sitting area of the

building. However, in general they have not faced any maintenance issue with the walls.

The two vertical woodworks on the internal part of the building hide recording equipment that was

installed by Nottingham Trent University to monitor the temperature and humidity levels in the RE wall, at

different depths and heights. The installation cost about 10,000-15,000£, but as far as Nigel is concerned

there has not been done any analysis of the collected data so far.

Overall, Nigel quoted that the temperature level is quite comfortable in the building and despite the

installed under floor heating system, occasionally they use gas heaters in the building. This is due to the

overcomplicated system of controlling the equipment and the lack of training of people that do not know

how to operate it.

The windows on the roof have automatic openers and they are programmed to open as the temperature

rises. This, however, caused problems as they were opening automatically in sunny winter days because of

the overheating of the glass, letting heat to be lost. In addition, there were problems with birds flying in from

the top and noise produced of the cracking of the windows. During the summer they could even find dead

flies in the middle of the building that had basically been fried by the heat up on the roof. Thus, they decided

to stop them opening, even if they could replace them with more controllable ones. Since then they have not

faced any overheating problems in the building during the summer, as the height of the roof is quite big and

permits to the lower space to remain at comfort levels.

Visitors of the building find it aesthetically appealing and as Nigel commented “this building does definitely

influence people, there is no question about this”. He added that their feedback is always positive and

occasionally people ask HHW if they design houses. Nigel’s opinion is that earth building suits most to self

build, as the mainstream builders and developers “are not even slightly interested and if you suggest them

that they would laugh at you; the only way you would motivate them is if there is a simple way of doing it”.

Labour work is seen as big cost for the mainstream building industry where dominates the mechanization

that accelerates the construction process.

- 37 -

He stated that even though stabilised RE quite often is more appealing to people, publicity and awards of

existing buildings make people be interested and gain confidence. Currently there are not many experienced

earth builders, it is hard to find them and the cost is significantly more than that of a mainstream building.

Although he would absolutely consider it for dwellings and private buildings, he concluded that it is not yet

an option for the general people.

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4.3.0.1 Pines Calyx Conference Centre General view

4.3.0.2 Pines Calyx Conference Centre Model

- 39 -

4.3 Pines Calyx Conference Centre

Location Pines Galyx, Beach Road, The Pines Garden, St. Margaret's Bay,

Dover,

Kent, CT15 6DZ

Date 2006

Client St Margaret’s Bay Trust/Pines Calyx

Architectural Design Helionix Deign

Issy Benjamin

Alistair Gould


Engineering

Cameron Taylor Group Limited

Philip Cooper

Massachusets Institute of Technology, Department of Civil and

Environmental Engineering

John Ochsendorf


Rowland Keable


Engineering

Pete Walker

Contractor/Developer Ecolibrium Solutions Ltd

Conker Conservation

Awards Institute of Structural Engineers Building Awards 2007

David Alsop Sustainability Award, Commendation

Best Small Building (under £1 million), Winner

London’s Sustainable City Award 2007

Best Sustainable Building

Building magazine Awards 2007

Sustainable Building of the year (small project)

Fig. 4.3 Pines Calyx Conference Centre – Project Information

4.3.1 Introduction

Pines Calyx Conference Centre is an earth sheltered building which consists of two interlocking drums of

12m diameter each. The key features of the building are the rammed chalk curved walls and the Catalan

vaulting domes. The south facing walls provide passive solar heating and the heat gained is absorbed by the

- 40 -

thermally massive construction, which together with a natural ventilation system, ‘virtual daylight’ lighting,

sustainable water management and PvT installation, make the building to be carbon negative in energy use.

4.3.2 Interview with Alistair Gould (09.07.2013)

Bay Trust found the opportunity of using the methodology of earth sheltered construction of extreme

importance for their location, as they wanted the landscape to be precedent in their design and a building

which is not “a big statement”. In their design brief they first set the target of creating an optimum and

healthy learning space. Sustainability came as a second motive, but actually blends in completely with the

first.

In terms of sustainability they wanted the building to be as low impact as possible and make use of local

materials. That is where the idea for using chalk came from. Alistair mentioned that at the beginning the

engineers were skeptic with this idea and “they were looking at me with funny looks when I was mentioning

the part of chalk”. They were questioning whether to make some of the walls in rammed chalk and others in

masonry, which found Alistair in totally disagreement as he claimed “that came to me as a disaster because

you either have to do the whole thing or not”. The collaboration with Pete Walker was important in providing

all the requisite tests but also in supporting the idea of rammed chalk as a possible and valuable solution. A

conference on RE at Bath University in 2003, where research results on RE and funding gained for further

research were presented, made the engineers gain confidence.

Alistair cited that getting a planning approval was “swift”. He explained that they have always tried to make

sure that there is an understanding of what they are doing with the parish council and local community and

thus there was no objection on that part. There were some issues due to the fact that they were proposing a

commercial building in a residential and conservational area, but at the end those were overcome. In fact he

stressed that “it was quite unusual to hear the planning officer saying when I first met him that he wanted

this to happen. That was nice to hear because I was used in having different ways of telling me no”.

The earth sheltered design took advantage of the topography and provided them with the essential row

construction material. All the chalk used was excavated from site, around 650tones. In order to be ready for

use a process of taking out all the big plinths was necessary. The team of Rowland worked together with the

subcontractors to build the rammed chalk walls and it took around two months to complete them. The outer

walls, of thickness 650mm, have been curved from the inside but have been facetted from the outside in

order to allow commercial insulation panels to be fixed directly to them. On the part of the building that is

double storey, they first built the ground floor walls and after the concrete slab was placed above them, they

continued on constructing the second floor walls. They used steel shuttering to form the walls in layers of

60mm rammed down to about 40mm. According to Alistair, it is notable that there was no shrinkage of the

rammed chalk walls, fact that impressed the engineers a lot.

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Actually, while the concrete slab was being poured they did a smaller trial building next to the conference

centre. At that stage they had already gained understanding and confidence about the rammed chalk but it

was still a good exercise for the construction team. This building was particularly helpful as a smaller scale

trial of the Catalan vaulting over the rammed chalk walls. A specialist team from MIT did the design-

modeling and came over in order to construct the dome. Until that moment they were intrigued to construct

- 43 -

the roof in that way but as long as they had not found the way to do so they were still thinking the reinforced

concrete roof as their fort back option. However, after that, the contractor was finally convinced that he was

capable of doing it and they continued with the two domes of the main building. The trial building now

functions as an information building showing and explaining visitors the process that had been followed.

The walls on the earth sheltered part have been carefully insulated from the back to block any dump

ingress into the building as this would be a significant threat. The external part of the walls have also been

insulated and lime rendered. In fact there is one wall on the back of the building made out of lime and hemp

blocks and another one from reinforced concrete, which were the engineers’ decision. Reinforced concrete

has also been used for the foundations, the pillars of the ground floor and the two interlocking ring beams on

the top of the walls. It was a sensible decision to use concrete only where was indispensable.

In the internal part the walls were sealed with a stabilising solution of calcium silicate to prevent the

dusting “so that many black suits do not get too much chalk on”, as Alistair said. They faced a minor issue

with some parts of the wall on the ground floor which continued to dust seasonally, probably because they

had not dried out enough. They consulted Rowland on this and with the addition of one more layer of

sodium silicon it was fixed. In the main space of the ground floor there is a sort of plinth installation within

the wall. It has been inspired from Martin Raush’s work and was created from Rowland following Alistair’s

suggestion.

In the building there are monitors installed that provide real time data on various parameters related to its

operation such as the thermal performance, energy use, energy generation, air flow. The building has

excellent thermal properties, being able to absorb heat and humidity to create a pleasant internal

environment. Its performance derives from the combination of the design principles with the sustainable

features of the building.

Speaking about people’s reaction and respond to the building, Alistair mentioned that he always get

comments about how “relaxing” is the space. According to him that is associated with the circled design and

the material of the building. As he explained “nature does not use the fugitive rectangles but curves, which

help people energetically with the flow”. Chalk has a tactile sense; its natural colour and breathability help

creating a pleasant environment. Alistair added that often people express their desire to use it in their

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- 45 -

houses. Actually, the starting point for the very initial sketches of the conference centre came from ideas

about designing his home.

Overall in the building it was implemented a very integrated design as they were applying different

eclectic methods that had not been put forward together in that way before. From a financial point of view

the building worked out at about 200£/m2, which is right for a public building, according to Alistair. In that

price it is included the built cost and the fees. The cost for all the research that has been done in order for

this building to become a reality is not included. However, Alistair emphasized that this was an important

part of their brief because the building represents a reference point to show that as an organization they can

plan and articulate practical sustainable solutions based on the site location and material availability. It might

have been “a kick on the budget” but the benefits come at two levels. Firstly, the knowledge obtained

ensures their capability of applying it into future projects. In fact, they have already passed on to the next

phase of designing accommodation units for conference-workshop delegates on site on the same logic.

Secondly, taking into account the operational efficiency of the building which is close to a neutral carbon

building the overall capital cost can be balanced.

Alistair concluded that “we did not start consciously with deciding to make the building using two of the

most ancient methods of building construction”. Their starting point was to make a healthy space and a low

impact building but he described as “interesting” the fact that they ended up by using rammed chalk and

Catalan vaulting, which are methodologies of 3,000 and 1,500 years old respectively. He pointed out that this

building demonstrates that in the 20th century “we think we are so clever that sometimes we miss the point

but we can always learn from the past”.

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4.4.0.1 Rivergreen Centre Section

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4.4 Rivergreen Centre

Location The Rivergreen Centre, Aykley Heads, Durham, DH1 5TS

Date 2005

Client Rivergreen

Architectural Design Jane Darbyshire and David Kendall Ltd

David Kendall

Kevin Turnbull

Ruth Walters


Engineering

Building Design Northern Ltd

Clive Oliphant

Earth Wall Consultants Simmonds Mills

Andy Simmonds

Ram Cast - CIC

Rowland Keable


Engineering

Pete Walker

Contractor/Developer Rivergreen

Tony Garrett

Mel Laidler

Alan Bowman

Awards RICS Sustainable Building of the Year 2007

RIBA Design Award 2007

Constructing Excellence NE Overall Winner 2007

The Journal Landmark of the Year 2006

Fig. 4.4 Rivergreen Centre – Project Information

4.4.1 Introduction

Rivergreen centre is a slightly off-set cruciform plan, two storey offices building. The central, east-west

spine is a top-lit, double-height atrium with a RE wall along the northern side. The spine acts as a natural

divide between two different office layouts in the building and fulfills several functions. Overall, the intention

at every stage, from the building orientation to the choice of materials, has been to try and minimize the

impact on the environment, given the natural constraints of the site and of the budget.

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- 49 -

4.4.2 Interview with Peter Candler (19.06.2013)

Rivergreen was operating a service office building quite close to Rivergreen Centre but the demands for

office accommodation were higher from its capacity and thus the idea for a new, bigger building came into

the table. In turning the idea into a reality the company’s aim was to make it an “ambitious project in every

sense of the word”. One of the ambitious aspects was to be responsible in terms of sustainability. Even

though sustainability was a very important principle in bringing the new project forward, it was not the main

driver. More than anything else the company wanted to create an office space that is a nice and positive

working environment.

The “period of pre design”, as Peter characteristically referred at, was a really important phase in the

conceptual process of the project. Before getting into the detailed design of the building the company looked

at other existing examples in UK in an attempt to learn from the practice and the related experts. The visit on

the visitors centre at CAT was extremely critical as it triggered the idea of including a RE wall in the new

building. However, before making the final decision the company wanted to make sure that they would have

the knowledge and skill to do that earth wall. In order to assess whether or not they were capable of doing it

they collaborated with Bath University and Rowland Keable. A lot of studying, engineering and soil properties

testing went inside the decision to build the earth wall. Furthermore, some panels of sample earth walls

were built in a controlled environment within another development of the company close by, using their

construction team. At that point the company had a good understanding of what it was required and a

feeling of confidence. According to Peter, it was not at all a “reckless decision”, hence it required a high

engineering work even though people commonly consider it as a “crude and almost prehistoric” material.

The design team worked together with the construction team (with Rowland Keable as coordinator-project

manager of the construction team) from the very beginning of the project. Even in the pre design studies and

during the decision making process Rowland played an important role. This is quite unusual but in their case

that was possible as Rivergreen was both the client-promoter and the contractor of the project. After its

construction the building is owned and operated by Rivergreen as well. This “unusual structure” of

Rivergreen that had a number of different roles in the project allowed them to do that. As Peter said “if a

contractor would be to build an earth wall as a construction contract with normal conditions of contract that

exist, they would be thinking very skeptically-carefully about it”.

The soil used to construct the earth wall was available on site. They excavated an area of around 500m2 for

the basement that was mainly sand, which is suitable for an earth wall, one more reason for integrating it in

their design. They decided that it made perfect sense to use a free material that otherwise it would have

been a “problem” for them, as they would have to pay for it to be taken offsite. To achieve the appropriate

consistency they mixed it with a little bit of clay and gravel sourced from local quarries, but approximately

80% of what was used was dug in-situ.

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The main challenge during the construction process was to keep the wall dry, which was a bit of a problem

without the roof having been constructed first. They had to cover it every day with plastic sheets and on

windy days these sheets were floating or moving. Because of that the surface of the earth wall has been

affected. The intended finished texture of the wall in some places is not perfect even though it is not

recognizable from a common eye. (eikona). No any finish liquid was applied to the earth wall after its

completion. There are some visible points that have been damaged from people who are touching the wall,

but again these are insignificant. In fact, at the lower part of the wall there have been added some glass

protection screens. Through the whole period that the building is operating only one person complained that

the earth wall had affected his respiration system, probably from the dust. There has not been any testing on

that, but Peter claimed that “there are no issues at all with dust”. Apart from that, they did not face any

other problem during the construction or any maintenance issue. According to Peter, this is largely because

the earth wall is a large internal partition of the building and thus all the common problems of earth walls

associated with risks of water or humidity ingression from the top are not relevant in their case.

In getting the planning permission they did not face any particular difficulty. There was only a doubt among

the engineers and Rowland about whether or not there was a fire risk, because the sand contained coal

fragments. The coal comes naturally in the ground of the wider area as it used to be a mining area, but the

building control was not concerned about that.

The wall has been constructed in vertical panels to avoid problems with thermal movement. They used

steel shuttering from both sides to form the wall as it is stronger than timber and the load of the earth was

quite big. It had been compacted with hand pneumatic rammers in layers of about 150mm that after

compaction came down to about 100mm. This creates a stratification effect on the wall which is actually the

main visible characteristic of the RE method. As Peter said, “when somebody looks at the wall it looks almost

as if you cut a section through the land, through the ground. It literally is the geology of this place, because all

the material comes out of here. It came out of the ground, either from the site or from places very close by. So

it literally represents the geology of Durham”.

The aesthetical and tact out quality of the wall fascinates every single person that visits the building from a

kindergarten child to the Prime Minister. As Peter mentioned even former Prime Minister Tony Blair, when

he came for the formal opening of the building, the first reaction to the wall was to touch it.

Speaking about the financial aspect of the earth wall Peter cited that “it probably was a bit more expensive

than an ordinary wall” but there were a lot of compelling reasons that lead to that decision. It did not attract

them only for its beautiful aesthetic appearance. Peter summarised the main reasons: “We had the material

on site which was a problem for us and was suitable for creating an earth wall; we had a design which used a

lot of light in the centre of the building and therefore heat gains, so we needed some sort of moderation of it.

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We wanted to show people that there are different ways of solving problems. They don’t always have to go

down the same path. We wanted the project to be a sort of example. So, all of those factors came together to

make us do it here”. Because they were dealing with an office building, the most important part of their

motivation was to create a healthy-pleasant environment and to inspire people to keep their minds open,

think in creative ways and not in train lines. Of course the earth wall is just one aspect of the building into

that direction. There are a number of other elements (natural ventilation, efficient use of resources, water

management, car park as an orchard, landscape and biodiversity preservation etc.) that work together at

different levels to fulfill the scope of this building.

Indicative of this concept of the building as an “educational tool” is the brief explanation of what the earth

wall is and how it was built, which can be found on a board in front of the earth wall in the main accessible

area of the building, aiming at informing visitors and users.

Within the RE wall there is not any monitor installed but Peter talked about the results of a post occupancy

study that has been conducted from Ove Arup consulting engineers. As he explained “their department in

London specializes in doing research on buildings and establishes how good the buildings are at fulfilling their

basic functions: being positive working environment, being comfortable in working, thermal comfort, energy

efficiency, use of resources and water etc”. According to their study the strategic objective of the earth wall

which is to help moderate temperature and humidity levels in the building is successful. Additionally, Peter

talked about academic researches that have studied the attitude of visitors and users of the building towards

the building and from the questionnaire they developed, most of their feedback from the people that are

working in the building is very positive.

Rivergreen has never done that before but after constructing this wall they can assure that it is very simple

and that “there is nothing inherently skilled difficult for making an earth wall”. It is more about an attitude as

it requires following carefully the process that can’t be rushed. It took them approximately three months to

complete it despite of the estimated time which was about the half. However, that fact did not hold up the

process of the whole construction as they could continue working normally on the rest of the building

around the earth wall.

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4.5.0.1 MPEP Educational Centre General View

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4.5 Educational Centre, MPEP

Location Mount Pleasant Ecological Park, Porthtowan, Cornwal, TR4 8HL

Date 2003

Client Mount Pleasant Ecological Park

Architectural Design Tim Stirrup

John Wray


Engineering

Chris Massey


Rowland Keable


Engineering

Pete Walker

Contractor/Developer Mount Pleasant Ecological Park

Awards -

Fig. 4.5 Educational Centre, MPEP – Project Information

4.5.1 Introduction

MPEP has been developed over the last 10 years as a community resource envisioned from Tim Stirrup,

who directs all aspects of the park development. Looking for workshop for his building company (Pioneer

Environmental Buildings) he discovered the land for sale which opened up a wider range of possibilities. The

educational centre is a rectangular plan building, which consists of a pre existing plinth wall on the back and

load bearing RE walls for the rest of the construction. It accommodates six workshop-training spaces and a

multi use venue space, from office to creative arts kind of use.

4.5.2 Interview with Tim Stirrup (13.07.2013)

In Cornwall the traditional building technique with earth is cob. However, John Wray (architect) had

worked in Australia with Rowland on RE and Tim had an experience of RE construction as he had participated

in the team of Genesis Project in Somerset and in projects in Morocco. Nevertheless his company is

specializing in timber constructions, their decision about which material to use derived from the local

availability. Tim explained that “North Cornish coast is bare of trees. If this was a forest, it would have been

built out of wood, because we wanted to use a material that was available locally and was very low impact”.

They were also thinking of straw bales as an option as they could grow it on site, but the option of RE was

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more appealing to them as earth is an abundant material and they could just take it straight from the

ground.

To determine whether the existing soil was suitable to construct load bearing walls they first had to test it.

They collaborated with Pete Walker at Bath University, where they delivered three tones of earth in order to

carry out erosion and compaction tests. Structurally the results were favorable, the earth tested having a

structural strength of 0.49N/mm2 (a standard concrete block is 3.5N/mm2). Although weaker than concrete

blocks its mass (the wall thickness is 400mm) gives it its strength.

However, the structural engineer was still not convinced from these results. A lateral loading wind test was

required, as it is a very windy area. For that reason they built a test earth wall on the site to simulate a strong

wind and see if the earth wall could withstand the pressure. They attached a plank at the top of the wall to

pallets and loaded with blocks, while any deflection was measured with micrometer. When the results were

analysed from the structural engineer he was amazed that this unsupported section had withstood the

equivalent of 300mph winds, whereas a concrete block would have fallen down. This strength is due to the

elastic properties of the earth – it can ‘flex’.

Having proved its capabilities to the structural engineer and Building Control (it was the first building to

gain planning permission in Carrick for over forty years) it was ready to build. That test was critical at

convincing the structural engineer who was really skeptic at the beginning. Tim emphasized that before the

test the structural engineer was continually asking him ‘why do you want to use earth as a construction

material; you can’t afford anything else?’ After that he was so impressed that now when he sees buildings

with concrete blocks he is wondering ‘why don’t they just use the earth?’

After the test they decided that they wanted to keep and use the test wall as an example of showing and

informing people about the construction of the building. Because the wall was totally unprotected from the

wind and rain they built a wall around it and a ‘roof’ to provide a degree of protection. The erosion that has

occurred because of the weather conditions is visible at two levels. Firstly, the outer fine and smooth layers

of the wall have disappeared resulting in a decrease of the wall thickness but also in expositing the gravels

that are in the middle, core mass of the wall. Secondly, the erosion of the wall has been occurred more in

the lower parts of the wall, demonstrative of the fact that the rain does not come totally vertical on the site.

On that test wall, there is an informative board which explains how the RE walls have been constructed.

Rowland was responsible for training the people on site on how to build the RE wall. He spent, together

with the site manager and a small team, about one week on site showing them the technique and then it was

all up to the construction team. Although earth is a free raw material, the construction of earth buildings is a

labour intensive and hard physical work process. It took a team of four people four months, which is long

time according to Tim for a building of that scale, to build about 288m2 of walls using nearly 300tones of soil.

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They decided to do the building on concrete reinforced beams, because there was mining activity in the area,

otherwise they could do it on stone plinths. Tim explained that the key to the RE way of building is to get the

right consistency of the mix and most critically to control the moisture content. He said characteristically “As

long as you have got one builder; a good builder who has experience and knows how to get a straight line

then the rest is unskilled labour”. In order to test the moisture content, which optimum should be 10%, they

did the drop test on site.

They used a special steel formwork to form the walls which was quite expensive. It cost them around

12,000£ to hire it. Tim said that they should have bought the formwork at the first place. It could have cost

more but then, they would be able to rent it out to other people and use it again. The walls were built in

vertical sections. They were building a section, leaving a gap, creating the next section and after two weeks,

when the first sections had drought out, they were infilling the gaps by constructing the in between sections.

After that process all the sections were taught together with a timber wall plate on the top.

Tim described the whole process of putting up the building as “quite industrial and noisy the way they did

it”. As he said the fact that they were hiring the formwork made them work into deadlines. They used a JCB

excavator to dig the soil out of the ground and move it to the area of the building, and pneumatic rammers

to ram the earth. Because they were very weather depended during the construction and had to protect the

walls until they got the roof on, they made what they call “top patch”, which was actually their design. They

made a simple version of the roof of the test wall and then made two big screens and placed them at the top

of the roof, coming down in an angle with plastic covering them. This system protected the wall from the rain

but it also enabled it to dry out. They could just wrap it in plastic but in that case it would not dry as quickly

as it did. According to Tim all that process was “a bit stressful when you are building, because you know you

are spending to a brand new building and before you even finish it, it is deteriorating and when you come

back after a heavy rain and windy weekend, it just runs out”. Some parts of the wall fell down and they had

to rebuild them or repair in certain areas. Even Tim remembers that were times when he was thinking “Why

did I choose earth?” But he admitted that at the end when all the formwork is taken off and the pristine,

monolithic earth wall is revealing, a sort of rewarding enjoyment comes.

At the internal part of the walls they applied sodium silicon as coating in order to stop the dusting coming

out of the wall. At the external part they applied a lime wash, which has been painted on the wall. By

applying that lime the texture of the earth is still visible. Only one section of the wall suffered a bit of

cracking and for that reason they used lime render on that particular section. Every year they have to re

apply the lime wash because the wall is exposed to horizontal wind and rain. By insulating the outside of the

wall with lime render/ wash they protected the wall but they were also able to get the right U-value. The

insulation does not permit the wall to act as thermal mass. However, due to the fact that the building mainly

operates as a workshop space which is used temporarily, that does not constitute a problem.

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Talking about people’s perception of the internal comfort conditions of the building Tim claimed that the

feedback he gets is that the earth walls work really efficiently as moisture regulators. When it is too wet they

release moisture and when it is too dry they absorb it, maintaining in that way the moisture at a pleasant

level.

Discussing with Tim and some of the people that work in the building about people’s reaction and attitude

towards the building, they all claimed that visitors are always positive when they come but the general

perception is that people lack of information. As they said “People are not aware that earth is a building

material. There is no publicity. Apart from the people that have gone into the Eden project. But in general

there is not so much information about it”. They stated that even if somebody knows about earth it is difficult

to proceed on constructing a private building as it is necessary to own a piece of land and also there is no

information on where to find the appropriate construction team that know this technique. They referred that

“If you want, for example to build an extension out of timber frame or concrete block, you could bring up any

builder. But if you want to do it out of earth where do you start? That is probably why people are put off”.

They all agreed that people are usually reassured more with concrete or stone as they like to think that

whatever they build will last forever. It is the same hesitation that they have for using timber; that it will not

last the same as stone or concrete. Tim gave an example of a dialogue he had with a few local people that

came to him during the construction process:

“(People) - You are really making a mark here, aren’t you?

(Tim) - I hope not!”

He wanted to emphasise that the whole point of using earth is that when the use of the building finishes, it

will just disappear or be recycled, something which is not easily possible with concrete.

Concluding, they have not calculated how much it would have cost them to construct the building in a more

conventional way, but the estimation shows that it was less than to build in concrete blocks. And even

though the formwork was expensive and the construction was labour intensive, Tim confirmed that it was a

conscious decision to use earth. Apart from the beautiful texture and colour, the whole point of building this

structure from RE is to show that it is a suitable building material for modern use.

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5. Data Analysis – Discussion

5.1. Introduction

The data presented in the previous chapter have been thematically analysed in order to allow for a

comparison to be conducted. The comparative analysis aims to explore possible patterns among the

presented case studies that:

- illustrate what is happening at the present and,

- identify what should probably change in the future to promote the RE technique for public and private

buildings in UK.

5.2 Analysis

5.2.1 Before the Construction

Motivation

One of the incentives, common for all the examined case studies, is the low environmental impact of

earth/chalk. All the interviewees agreed that the material availability - abundance, on site or in close

proximity, played crucial role in their decision to use it as a construction material. Otherwise, they would

have considered other building methods. It is important to note that the idea for using earth/chalk was

always the client’s initiative. In four out of five case studies, with the exception of Rivergreen, a sustainability

background had always been among the client’s general philosophy and a fundamental value of its ethos.

The inclusion of earth/chalk derived from a holistic approach of the design of the building, along with other

construction techniques and materials, to act as inspirational point for showing people that a modern

building can be beautiful, environmentally friendly and a healthy environment just by using simple materials

and techniques.

Awareness of precedent buildings

In all five case studies the interviewees highlighted the importance of knowing and having visited

precedent RE/chalk buildings. The exposure of the involved people to existing buildings, both in UK and other

countries, gave them confidence that this technique can be successful and encouraged them to follow a

similar approach in their buildings. It is clear that based on the combination of this awareness with research

and experts’ consultancy people were actually able to make their decision. Research on RE/chalk technology

was extremely important, but it would have not been enough without any real examples.

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People involved in the decision making process

In all five case studies the use of RE technique was the client’s vision. It would have not been possible to be

transformed into a real project without the close collaboration of the architects with Rowland and the

engineers. The cases of Rivergreen and MPEP were special as the clients were also the contractors, which

made the whole process easier. On the contrary, the cases of Pines Calyx and WISE show that the contractors

were skeptic and were interfering negatively in the decision.

5.2.2 During the Construction

Soil supply and testing

For all the case studies laboratory tests were required to be carried out in order to evaluate the soil

suitability. Soil samples were sent to Bath University with Pete Walker to be in charge of that. In two (HHW,

MPEP) of the case studies the ‘drop off’ test was selected as the appropriate method to test every day the

humidity level of the mix on site. Only in WISE the existing ground properties did not support the earth

construction and the soil was sourced from quarries close by. Rivergreen was the only case where it was

required to add extra soil from quarries in order to get the desired consistency.

Construction team and training required

Rowland Keable, together with his team, was the responsible one for training each contractor’s

construction team. He was hired for all the case studies as a consultant and trainer but in the case of Pines

Calyx he also collaborated with the construction team to actually build the walls. Only few days of training

and guidance were enough to ensure that each construction team would be capable to cope with the certain

demands of RE technique. In that way, Rowland is spreading the knowledge among mainstream builders.

Construction Process

Smaller sample walls were required to be constructed in three out of five case studies (Rivergreeen, MPEP,

Pines Calyx) to convince the engineers and contractors that the earth walls can stand, but also as an exercise

for the construction team.

The key to the success of the construction is to find the right earth/chalk mix and to keep its humidity level.

As long as this has been secured it is all about the shuttering and the ramming. The case studies demonstrate

that the range of shapes and forms that can be achieved depend mainly to the time and cost of the project

but also to the construction team’s experience. Empirical rules developed from experience are crucial as can

perfect the required skills, help avoid mistakes and invent ‘patents’ to facilitate the construction process.

Such is the case of PMEP, where it was designed a certain protection system for the rain, and the case of

WISE, where it was used a specific type of rammers to accelerate the construction. The main enemy of the

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RE/chalk construction is the rain, especially in UK. All the interviewees agreed that it would be a beneficial

investment to construct a temporary roof or lift temporarily the permanent roof and work undercover, as it

would have saved time, effort and money, but would also ensure the maximum quality of the wall’s mass

and surface. They added that the option of buying the shuttering or making their own would also be

beneficial in a long term period.

5.2.3 After the Construction

Maintenance

The examination of all the case studies showed that apart from minor issues there has not been detected

any serious maintenance issue after the completion of the walls and during the operation of the building.

With the appropriate provision for insulating and damp proofing the external exposed parts and protecting

the surface from damages (from furniture and users) on the internal part, the durability and the aesthetic

quality of the wall can be retained.

Energy and environmental performance

In all the case studies interviewees described the indoor air quality as satisfactory and the temperature-

humidity levels inside the building as comfortable for the most days of the year. Among other factors, they

related that comfort to the hygroscopic proprieties of earth/chalk walls, but also to their potential to act as

heat mass. In all the buildings additional supporting heating systems are being used occasionally. The

interviewees pointed out the importance of combining earth walls with south glazing facades in order to

maximise the heat gains and their distribution. The combination of earth walls with roof open able windows

(WISE, Rivergreen, Pines Calyx) provides an efficient solution for controlling the lighting and natural

ventilation of the building.

Users’ attitude

All the case studies demonstrate that an earth building can be desirable, pleasant, stimulating and

inspiring. The common perception that earth is a humble material and not modern enough (Adams and

Elizabeth 2005) was proven misleading. It is obvious that there is a lack of awareness from people’s part

about earth, its opportunities and its modern applications. It is clear that publicity and awards have an

impact on motivating, shaping and changing people’s thinking and attitude towards earth as a construction

material. However, it still remains the necessity to look at ways of making earth buildings more accessible

and affordable solution for the wider public.

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5.3 Overview

The use of manufactured RE blocks is what happens most commonly worldwide (Walker et al. 2005). This is

because it permits a relatively quick and cheap construction, whereas in situ RE is a dry technology and an

intense labour technique. In countries with dry climate or in countries where labour is cheaper this technique

makes more sense, than in UK where those two parameters are not valid.

The case studies analysis shows that people can get inspired from public RE buildings. Even though not all

of the interviewees are convinced that earth buildings can or will be a common feature in UK in the near

future, they agreed that this technique has the potentials to be suitable for private buildings and dwellings,

under the fulfillment of the right conditions.

Among engineers and contractors there is a perception that earth structures are not as structurally sound

as concrete, brick or timber frame constructions. Mainstream contractors and big developers would hardly

agree to build a RE housing project without any specific interest and pressure from the part of the client. In

housing projects, though, it is quite rare that the client-final user will have been established from the very

beginning of the construction process. Thus, it is obvious that RE technique suits most self build

constructions, otherwise a more practical and attractive RE housing model should be developed to be

saleable to people on behalf of the contractors.

In case of self building the most critical problem to overcome is the difficulty to get access to land, but also

to experienced builders. The idea of ‘community level trust’, explained by Nigel, might be a solution as it

enables a group of people to acquire land for development. People become part owners in the land; they

sign payment agreements to the community and then the community can get the planning permission and

control what will be built.

In terms of introducing the RE technique into the mainstream construction industry it should be considered

that the industrial level would demand the mechanisation of the earth mix selection and the testing process,

as the industrial construction is defined by a consistent and standard system. In that way, though, the

concepts of sustainable site management and in situ construction disappear.

A possible housing model, that could be promotable to the best interest of both the users and the

contractors, would be a combination of construction methods. That is to say, south facing RE massive walls

to take advantage of heat gains and storage, and a lighter material or better insulation from the north to

address heat retention inside the building.

Another option would be to develop a standard house design and acquire enough shuttering to do the

whole building simultaneously. Using the idea of premade boxes for the openings (interview with Nigel), the

construction could be really easy and quick as it does not involve any formwork difficulties or special fixing

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skills. That approach could be even more effective if combined with a portable roof system. That means that

the roof is first built and lifted high in order to offer protection for the construction of the earth walls and

finally, after the completion of the walls, is lowered down and fixed on them.

Concluding, it worth mentioning that the initial cost of RE buildings might be higher than mainstream

methods, but the payback time with the energy savings included, make them an investment as an option.

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6. Conclusions

6.1 Introduction

The aim of this dissertation was to evaluate the current situation of RE building activity in UK.

The main objectives were:

a) to analyse the knowledge needed in order to make a RE building and highlight the challenges of the

practical implementation of this knowledge in modern RE projects

b) to investigate the set of people who need to be involved for a RE project to become a reality and identify

how are all these people interlinked through the knowledge and the power they possess

c) to define and discuss considerations related to current limitations and future opportunities for further

expansion of this construction method on public and private level

6.2 Key Findings

The analysis shows that confidence with earth buildings is gained through exposure to such buildings and

the knowledge on RE method is gained mostly through experience. Research that is being conducted leads

the way to engineers and contractors to be more open on that construction method.

Currently construction teams lack of training on RE technique. However, few days of training are enough to

deliver successful complex building projects. Probably, the advantage of this method is that does not require

skilled labour and thus it could become the power of the contractors who do not need to employ a special

team but just the trainer. Rowland follows that direction in training the contractors’ team and imparting the

knowledge. Furthermore, the analysis highlights that even the most skeptic engineers at the end can be

convinced from the capabilities of earth as construction material, as long as it meets the specifications. The

fact that all the examined projects were challenging in engineering terms but proved to meet the engineer’s

standards is encouraging.

The analysis proves that current applications of RE buildings raise public awareness. It points the way to

society and policy makers that people need to be given examples which demonstrate that a building with a

good environmental performance can still be appealing and desirable. RE buildings are currently a

consumer lead activity, but could have an impact on the construction industry as construction industry

market changes according to the demands.

6.3 Evaluating the Methodological Approach

At the beginning of this dissertation, it was intended an analysis of all buildings listed in Fig. 2.1, so as to

make a profound research and come to a sound judgment regarding the present and future of RE

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construction. However, as that was not a realistic scenario because of time limitation and cost budget, it was

decided to focus on five case studies and look them into more depth. They were selected carefully in order to

allow for reliable conclusions to be drawn that can be generalised. If the circumstances would permitted it, I

would analyse all the buildings by taking interviews from the majority of the people involved in every one

and I would also come into contact with Rowland Keable.

6.4 Recommendations

The analysis demonstrates that RE buildings can inspire people and stimulate debate in the society. It arises

the need to look at ways of making earth buildings a more accessible and affordable choice for businesses

and individuals. Small steps of incremental demand for public RE development projects may be a realistic

approach in guiding the orientation of the mainstream construction industry. Additionally, dissemination of

good quality; up to date information to the public and industrial sector could assist and steer organizations,

businesses and individuals in pursuing earth buildings and helping reduce the impact on climate change that

construction makes.

UK Government’s low-carbon agenda promotes and finances the construction of new affordable homes to

level 4 of the Code for Sustainable Homes, using a mix of renewable materials which will help educate

developers and contractors on the use of new systems such as timber frame with hemcrete, the Modcell

straw bale system, Pavatherm system (BRE).

In that context, earth building industry could hopefully be seen as an option in the horizon of UK

Government’s sustainability agenda.

The analysis shows that construction time and cost come high in the priorities of mainstream contractors.

Looking into ways of providing greater opportunities for mechanization in construction in situ could push

behind some of their barriers. The creation of a platform on exchanging information would be a significant

step in establishing a knowledge base for the future.

6.5 Future Research

The main opposition argument to earth buildings relates to the weakness of its durability and structural

ability for big structures. Further research on alternative stabilisation products with low embodied energy

could possibly lead to solutions that balance between structural and environmental efficiency.

6.6 Overview

It is hoped that this dissertation will provide testimony, to both enthusiasts and skeptics on the merits of

the RE constructions. In the broader context, both small individual and large institutional efforts can deliver

elegant earth buildings with the best green credentials.

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Archaeological Contexts. British Archaeological Reports International Series S2116. Oxford: Archaeopress.

Correia, M., Dipasquale, L. and Mecca, S. (eds) (2011) Terra Europae Earthen Architecture in the European

Union. Edizioni ETS.

Dominowski, R. (1980) Research Methods. London: Prentice-Hall.

Easton, D. (1996) The rammed Earth House. Vermont, Chelsea Green Publishing Co.

Font, F. and Hidalgo, P. (2011) La tapia en Espana. Tecnicas actuales y ejemplos. Informes de la

Construccion 63: pp.21-34.

Givoni, B. (1969) Man, Climate and Architecture. Amsterdam; London: Elsevier Publishing.

Gomez, I.M., Lopes, M. and Brito, J. (2011) Seismic resistance of earth construction in Portugal. Engineering

Structures 33: pp.932-941.

Gourley, B. and Hurd, J. (eds) (2000) Terra Britannica. A Celebration of Earthen Structures in Great Britain

and Ireland. Maney Publishing.

Groat, L. and Wand, D. (2013) Architectural Research Methods.Hoboken: Wiley.

Hall, M. and Djerbib, Y. (2004) Moisture ingress in rammed earth. Part 1 – The effect of soil particle-

size distribution on the rate of capillary suction. Construction and Building Materials 18: pp.269-280.

Hall, M. and Djerbib, Y. (2004) Rammed earth sample production. Context, recommendations and

consistency. Construction and Building Materials 18: pp.281-286.

Hall, M. and Djerbib, Y. (2006) Moisture ingress in rammed earth. Part 2 – The effect of soil particle-size

distribution on the absorption of static pressure-driven water. Construction and Building Materials 20:

pp.374-383.

Hall, M. and Djerbib, Y. (2006) Moisture ingress in rammed earth. Part 3 – Sorpitivity, surface receptiveness

and surface inflow velocity. Construction and Building Materials 20: pp.384-395.

Hall, M., Lindsay, R. and Krayenhoff, M. (eds) (2012) Modern earth buildings. Materials, engineering,

constructions and applications. Woodhead Publishing.

Harris, C. and Borer, P. (1998) The Whole House Book. Machynlleth: Centre for Alternative Technology.

Houben, H. and Guillaud, H. (1994) Earth Construction. A comprehensive guide. London:

IntermediateTechnology Publications.

Jaquin, P.A. (2008) Analysis of Historic Rammed Earth Construction. PhD Thesis, Dept. of Civil Engineering,

Durham University – School of Engineering, Durham, UK.

- 70 -

Jaquin, P.A. and Augarde, C.E. (2012) Earth building: History, science and conservation. Bracknell: HIS BRE.

Jaquin, P.A., Augarde, C.E. and Gerrard, C.M. (2007) Historic rammed earth structures in Spain: construction techniques and a preliminary classification. International Symposium on Earthen Structures, 22-24 August 2007, Bangalore, India. Bangalore, India: Interline Publishing. Jaquin, P.A., Augarde, C.E. and Gerrard, C.M. (2008) A chronological description of the spatial development of rammed earth techniques. International Journal of Architectural Heritage 2: pp.377-400. Jaquin, P.A., Augarde, C.E. and Legrand, L. (2008) Unsaturated characteristics of rammed earth. Unsaturated Soils: Advances in Geo-Engineering, Toll et al. (eds), pp: 417-422. Jimenez Delgado, C. and Canas Guerrero, I. (2006) Earth building in Spain. Construction and Building

Materials 20: pp.679-690.

Jimenez Delgado, C. and Canas Guerrero, I. (2007) The selection of soils for unstabilised earth building: A

normative review. Construction and Building Materials 21: pp.237-251.

Kapfinger, O. and Rauch, M. (2001) Martin Rauch Rammed Earth. Berlin: Birkhäuser.

Keable, J. (1996) Rammed Earth Structures. A Code of Practice. London: Intermediate Technology

Publications.

Keefe, L. (2005) Earth building. Methods and materials, repair and conservation. London: Taylor & Francis.

Kiroff, L. and Roedel, H. (2010) Sustainable Construction Technologies: Earth Buildings in New Zealand.

Proceedings of 2nd International Conference on Sustainable Construction Materials and Technologies, June

28-30, 2010, Universita Politecnica delle Marche, Ancona, Italy.

Lax, C. (2010) Life Cycle Assessment of Rammed Earth. Dissertation for MEng Civil and Architectural Engineering, Dept. of Architecture and Civil Engineering, University of Bath. McHenry, P. (1984) Adobe and Rammed Earth Buildings. Design and Construction. New York: Wiley

Interscience Publication.

Minke, G. (2000) Earth Construction Handbook: The building Material Earth in Modern Architecture.

Southampton: Witt Press.

Minke, G. (2006) Building with earth. Design and technology of a sustainable architecture. Basel:

Birkh user.

Mortion, T. (2010) Earth Masonry: Design and Construction Guidelines. HIS BRE Press.

NMAC (2006) NMAC: 14.7.4: Housing and Construction: Building Codes General: New Mexico Earthen

Building Materials Code. Santa Fe: New Mexico Regulation and Licensing Department.

Norton, J. (1997) Building with Earth. A handbook. London: Intermediate Technology Publications.

- 71 -

NZS 4297: 1998 (1998) New Zealand Standard. Engineering design of earth buildings. Wellington: Standards

New Zealand.

NZS 4298:1998 (1998) New Zealand Standard. Materials and workmanship for earth buildings. Wellington:

Standards New Zealand.

NZS 4299:1998 (1998) New Zealand. Earth buildings not requiring specific design. Wellington: Standards

New Zealand.

Pacheco-Torgal, F. and Jalali, S. (2012) Earth construction: Lessons from the past for future eco-efficient

construction. Construction and Building Materials 29:pp.512-519.

Pearson, G. (1992) Conservation of Clay and Chalk Buildings. Donhead Publishing.

Rael, R. (2009) Earth architecture. New York: Princeton Architectural; Enfield: Publishers Group UK

distributor.

Reddy, V. and Kumar, P. (2010) Cement stabilised rammed earth. Part A: compaction characteristics and

physical properties of compacted cement stabilised soils. Materials and Structures 44: pp.681-693.

Reddy, V. and Kumar, P. (2010) Cement stabilised rammed earth. Part B: compressive strength and stress-

strain characteristics. Materials and Structures 44: pp.695-707.

Reddy, V. and Kumar, P. (2010) Embodied energy in cement stabilised rammed earth walls. Energy and

Buildings 42: pp. 380-385.

Rui, S., Daniel, O., Tiago, M., Carolina, E. and Numo, C. (2012) Rammed earth. Feasibility of a global concept

applied locally Sociedade Portuguesa de Geotecnia.

SAZS (2001) Standards Association Zimbabwe Standard 724:2001: Standard Code of Practice for Rammed

Earth Structures. Harare: Standards Association of Zimbabwe.

Silva, R., Oliveira, D., Miranda, T., Cristelo, N., Escobar, M. and Soares, E. (2013) Rammed earth construction

with granitic residual soils. The case study of northern Portugal. Construction and Building Materials 47:

pp.181-191.

Standards Australia and Walker, P. (2002) HB 195. The Australian earth building handbook. Sydney

(Australia): Standards Australia.

Taylor, P. and Luther, M.B. (2004) Evaluating rammed earth walls: a case study. Solar Energy 76: pp.79-84.

Taylor, P., Fuller, R.J. and Luther, M.B. (2008) Energy use and thermal comfort in a rammed earth office

building. Energy and Buildings 40: pp.793-800.

Trotman, P. (2006) Earth, clay and chalk walls: inspection and repair methods. BRE publication, BRE Press.

- 72 -

Walker, P., Keable, P., Marton, J. and Maniatidis, V. (2005) Rammed earth: Design and Construction

guidelines (EP 62). Watford: BRE Bookshop.

Walker, P. and Maniatidis, V. (2003) A Review of Rammed Earth Constructions. For DTi Partners in

Innovation Project ‘Developing Rammed Earth for UK Housing’, Bath, UK: University of Bath.

Walker, P. and Maniatidis, V. (2003) UK National Guidelines for Rammed Earth. Proceedings 9th International

Conference on the study and conservation of earthen architecture, Yazd, Iran, Nov.- Dec. 2003, pp.377-387.

Weisman, A. and Bryce, K. (2006) Building with Cob. Devon: Green Books.

Williams-Elis, C., Eastwick-Field, J. and E. (1999) Building in co is and sta ili ed earth. Shaftesbury:

Donhead.

Wolfskill, L. (1980) Handbook for building homes of earth. Greeley: Rammed earth Institute, International.

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8. Useful Internet Addresses and Links

http://www.ktponline.org.uk/ (accessed on 11/08/2013)

http://www.rammed-earth.info/ (accessed on 11/08/2013)

http://www.greenspec.co.uk/rammed-earth.php (accessed on 11/08/2013)

http://www.culture-terra-

incognita.org/index.php?option=com_content&view=article&id=13&Itemid=14&lang=en (accessed on

11/08/2013)

http://www.cat.org.uk/index.html (accessed on 11/08/2013)

http://blog.cat.org.uk/2011/06/30/riba-award-videos-about-the-wise-building-and-architecture-at-cat/

(accessed on 11/08/2013)

http://www.hillholtwood.com/ (accessed on 11/08/2013)

http://www.mpecopark.co.uk/ (accessed on 11/08/2013)

http://www.rivergreencentredurham.co.uk/ (accessed on 11/08/2013)

http://www.conkerconservation.co.uk/ (accessed on 11/08/2013)

http://pinescalyx.co.uk/ (accessed on 11/08/2013)

http://www.helionix.com/html/chalkwalls.html (accessed on 11/08/2013)

http://www.youtube.com/watch?v=tk-kNtEBDUo (accessed on 18/08/2013)

http://www.youtube.com/watch?v=jrI2PlHwLv8 (accessed on 18/08/2013)

http://www.youtube.com/watch?v=vVgSmnhVhhs (accessed on 18/08/2013)

http://www.youtube.com/watch?v=icbmN7fnVrc (accessed on 18/08/2013)

http://www.youtube.com/watch?v=uwcBTCkcweI (accessed on 18/08/2013)

http://www.youtube.com/watch?v=7UCCHRJpEis (accessed on 18/08/2013)

http://www.youtube.com/watch?v=8Omxgyw7GW8 (accessed on 18/08/2013)

http://www.youtube.com/watch?v=jTBvV6b6LGo (accessed on 18/08/2013)

http://www.youtube.com/watch?v=1MbvBLKhjRw (accessed on 18/08/2013)

http://www.youtube.com/watch?v=BXaTuxIk2XQ (accessed on 18/08/2013)

http://www.youtube.com/watch?v=OjIPhzdrMPQ (accessed on 18/08/2013)

http://www.youtube.com/watch?v=vORcB7ygVBc (accessed on 18/08/2013)

http://www.youtube.com/watch?v=RFGclxL-6Lw (accessed on 18/08/2013)

http://www.ktponline.org.uk/

http://www.rammed-earth.info/

http://www.greenspec.co.uk/rammed-earth.php

http://www.culture-terra-incognita.org/index.php?option=com_content&view=article&id=13&Itemid=14&lang=en

http://www.culture-terra-incognita.org/index.php?option=com_content&view=article&id=13&Itemid=14&lang=en

http://www.cat.org.uk/index.html

http://blog.cat.org.uk/2011/06/30/riba-award-videos-about-the-wise-building-and-architecture-at-cat/

http://www.hillholtwood.com/

http://www.mpecopark.co.uk/

http://www.rivergreencentredurham.co.uk/

http://www.conkerconservation.co.uk/

http://pinescalyx.co.uk/

http://www.helionix.com/html/chalkwalls.html

http://www.youtube.com/watch?v=tk-kNtEBDUo

http://www.youtube.com/watch?v=jrI2PlHwLv8

http://www.youtube.com/watch?v=vVgSmnhVhhs

http://www.youtube.com/watch?v=icbmN7fnVrc

http://www.youtube.com/watch?v=uwcBTCkcweI

http://www.youtube.com/watch?v=7UCCHRJpEis

http://www.youtube.com/watch?v=8Omxgyw7GW8

http://www.youtube.com/watch?v=jTBvV6b6LGo

http://www.youtube.com/watch?v=1MbvBLKhjRw

http://www.youtube.com/watch?v=BXaTuxIk2XQ

http://www.youtube.com/watch?v=OjIPhzdrMPQ

http://www.youtube.com/watch?v=vORcB7ygVBc

http://www.youtube.com/watch?v=RFGclxL-6Lw

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9. Pictures' Sources

4.1.0.1 - http://www.cat.org.uk/

4.1.0.2 - http://www.cat.org.uk/

4.1.1 - Personal Archive








4.1.9 - http://www.rammed-earth.info/

4.2.0.1 - Personal Archive






















4.4.0.1 - http://www.rivergreencentredurham.co.uk/






http://www.rivergreencentredurham.co.uk/

- 75 -



















- 76 -

Appendix A: Participant Information Sheet as sent to the interviewees

Participant Information Sheet

1. Research Project Title

Review of buildings with rammed earth elements in UK.

2. Invitation Paragraph

You are being invited to take part in an interview as part of a research project. Before you decide it is

important for you to understand why the interview is being done and what it will involve. Please take time to

read the following information carefully. Ask me if there is anything that is not clear or if you would like more

information. Take time to decide whether or not you wish to take part. Thank you for reading this.

3. What is the interview’s and project’s purpose?

The purpose of this project is to understand in depth the construction of rammed earth buildings over the

last three decades in UK. In particular this research concentrates on three main objectives:

1. Detailed architectural documentation and mapping of all the existing buildings with rammed earth

elements in UK.

2. Analysis and understanding of the phenomenology and human experience in the examined buildings.

3. Analysis and understanding of how the examined buildings respond to climatic issues.

The interview consists of a set of questions related to your particular involvement in one or more of the

examined buildings and will last approximately 15-30 minutes in total. You can drop-out the interview at any

moment, without giving any reasons and without any implications to you.

4. What are the possible benefits of taking part?

While there are no immediate benefits for those people participating in the project, it is hoped that this work

will disseminate and encourage the use of rammed earth as the heart of future sustainable construction

materials.

5. Will my taking part in this project be kept confidential?

All the information collected will be treated as completely confidential by the researcher. Your particular

involvement status to the project may be mentioned, but all your personal information will be protected and

will be anonymous.

6. Who is organizing and funding the research?

This research is part of my dissertation project for the completion of the MSc in Sustainable Architectural

Studies program at Sheffield School of Architecture.

7. Who has ethically reviewed the project?

This research has received ethical approval from the University of Sheffield, School of Architecture Ethics

Committee, and is supervised by Dr Lucy Jones ([email protected]).

- 77 -

8. Will I be recorded, and how will the recorded media be used?

The audio recordings of your answers during this interview will be used only for analysis. No other use will be

made of them without your written permission, and no one outside the project will be allowed access to the

original recordings.

9. Contact for further information

Thank you for your assistance. Please do contact me in case that you have any doubt or you need to add any

new information to this research project.

Christina Antonelli ([email protected])

mailto:[email protected]

- 78 -

Building Internal

Wall

External

Wall

Wall

Height

Foundations Footings Floor Roof Surface Coatings Damp Proofing Window

and Door Frames

Structural

Wall

Non Structural

Wall

Hill Holt

Wood

Venue

Centre

350-500mm 350-550mm 3m Insulation

300mm

Limecrete

Concrete

reinforced with

steel ribbon

Bricks with

insulation filling

in between to

avoid heat

losses of the

earth walls

Floor Mosaic with

under floor heating

system

Reciprocal Timber

Frame roof

(construction and

cladding)

Timber ring beam on

top of the wall

Outside:

1.Woodwaste Insulation

2.Fiberboard

3.Lime Render

Inside:

Exposed Rammed earth with use of

finish liquid

1. Protecting

Membrane

2. Drainage System

Timber

Rivergreen

Centre

500mm - 6m

Concrete Concrete Terrazzo tiles in the

corridors and café

area

High durability nylon

carpet tile on thick,

recycled foam

backing for the rest

of the building

Glazing Top

Supported by Timber

Trusses

Exposed Rammed earth without

any use of finish liquid

- -

Pines Calyx

Conference

Centre

650mm 300mm 7m at

their

tallest

Concrete Concrete Recycled timber floor Timbrel (Catalan)

Vaulting

supported by

reinforced concrete

beam on top of the

wall

Outside:

1.Waterproof membrane

2.EPS insulation

3.Lime Render

Inside:


calcium silicate

1. Protecting

Membrane

2. Drainage System

Aluminium

Educational

Centre,

MPEP

400mm 400mm 3m Reinforced

concrete beams

Concrete Timber floor on

rammed earth

Recycled rubber tiles

cladding supported

by timber trusses

and a timber wall

plate on top of the

walls

Outside:

Lime wash,

Lime render only in one section

Inside:


sodium silicon

1. Protecting

Membrane

2. Drainage System

Timber

WISE Lecture

Theatre, CAT

500mm - 7.2m Limecrete Sand lime Bricks

with limecrete

filling in

between to

avoid heat

losses of the

earth walls

Soft plywood panels Ultra thin stainless

steel cladding

supported by timber

trusses

And a plywood ring

bean on top of the

walls

Exposed Rammed earth with partly

use of sodium silicon

- Timber

Appendix B: Comparative Table of case studies’ structural characteristics

review of rammed earth buildings in the uk

Documents