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INTRODUCTION TO THIN JOINT MASONRY & SUSTAINABLE CONSTRUCTION

A short bridging course for practitioners in the Construction Sector

In December 2016, Calderdale College commenced delivery in York, North Yorkshire and East Riding of an ESF funded programme entitled Higher Level Skills for the Workforce.

The aim of the programme is to provide individuals working in the area covered by the York, North Yorkshire and East Riding Local Enterprise Partnership with the opportunities to develop the skills that will enable them to progress in employment and to support employers to develop individuals to fill higher-level skills gaps and shortages.

One of the programme elements focuses on the provision of specific vocational short courses for employees in order to enable them to progress in work within certain priority sectors (including the Construction sector) identified by York, North Yorkshire and East Riding Local Enterprise Partnership.

The programme’s Management Group has identified Introduction to Thin Joint Masonry as a short course that fills a gap in the current training market and has subsequently endorsed its development.

HCUK Training Ltd - an Associate of Calderdale College – has designed the course on behalf of the College.

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Contents Introduction to the Course .............................................................................................................. 4

Course Specification ......................................................................................................................... 4

Purpose and Aim of the Course ................................................................................................. 4

Target Audience ............................................................................................................................. 4

Rationale........................................................................................................................................... 4

Sector Needs ................................................................................................................................... 4

Potential Job Roles for Those Working Towards This Qualification ............................... 5

Progression Opportunities .......................................................................................................... 5

Delivery Methodology ................................................................................................................... 5

Grading and Assessment ............................................................................................................ 5

Assessment Strategy .................................................................................................................... 5

Course Materials ................................................................................................................................ 7

Scheme of Work ............................................................................................................................. 7

Lesson Plans ................................................................................................................................. 11

Course Resources ........................................................................................................................... 16

Baseline Assessment and Evaluation .................................................................................... 16

The Push to reduce Carbon in Construction ........................................................................ 18

Sustainable materials ................................................................................................................ 18

Waste management ................................................................................................................... 18

Transportation ............................................................................................................................. 19

Thin Joint Introduction ............................................................................................................... 20

Thin Joint Basics ......................................................................................................................... 20

A Speedy Project .......................................................................................................................... 21

Features of a Thin Joint System .............................................................................................. 21

Resources Required .................................................................................................................... 22

Mixing Processes ......................................................................................................................... 23

Movement Ties and Joining ...................................................................................................... 23

Wall Ties for Thin Joint Systems.............................................................................................. 23

Twist Ties..................................................................................................................................... 24

Flat Steel Ties ............................................................................................................................. 24

Abutment Wall Ties .................................................................................................................... 24

Movement Joint Ties .................................................................................................................. 24

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Tools Needed for Thin Joint System ...................................................................................... 24

Cutting Components ...................................................................................................................... 25

Protecting materials and completed work .................................................................................. 25

Working with Materials ............................................................................................................... 25

Positioning Materials .................................................................................................................. 25

Separating or Party Walls ......................................................................................................... 26

Methods of Construction Using the Thin Joint System ......................................................... 26

Assessment ................................................................................................................................... 26

1. Preparation for Evaluation. ................................................................................................... 27

2. Evaluation of method ............................................................................................................. 27

Completing Practical Assessment of process and evaluation of method and materials. 27

Course Resources ........................................................................................................................... 27

Case Studies ................................................................................................................................. 28

Learner Activities for Case Studies ......................................................................................... 28

Handouts for Study ..................................................................................................................... 28

PowerPoint Presentation ........................................................................................................... 29

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Introduction to the Course

Modern methods of construction (MMC)

The construction industry embraces innovation and modern methods of construction (MMC) by offering concrete solutions which can be used to reduce construction time and promote sustainable development, as well as offering cost savings.

Thin Joint Masonry

Thin Joint Masonry allows the depth of the mortar to be reduced from 10mm to just 3mm or less, resulting in faster laying and improved productivity, particularly on long runs of walling. Construction speed can be further increased by some 13.5 per cent using large-format concrete blocks, which have a face size equivalent to two traditional concrete blocks. The mortar cures rapidly, achieving full bond strength within one to two hours, eliminating the problem of 'floating' therefore enabling more courses to be laid per day.

Course Specification

Purpose and Aim of the Course This qualification is appropriate for employees in the Construction and the Built Environment sector working across a broad range of areas. It is designed to assess occupational competence in the workplace where learners are required to demonstrate skills and knowledge to a level required in the construction industry.

Target Audience HCUK policy is that the qualification should:

Be free from any barriers that restrict access and progression Ensure equality of opportunity for all wishing to access the qualification.

The course would be aimed at all tradesmen wishing to progress within their own trade specialism. This equates to 177,000 trades people in the Yorkshire and Humber region. With the required increase in the UK of an additional 224,000 trade people it would be a popular addition to the CPD requirements of industry professionals.

Rationale The demand for housing in the Northern Powerhouse currently outstrips supply by some margin. Developers are opening sites at a rate of one per week in the region. There is a lack of diversity within the industry with additional skills away from the core wet trades. Developers are using innovative systems within the build programs and this includes modern methods of construction. The drive, by developers, to reduce the time taken for full construction completions. Innovative build design and skills diversity is part of that drive. Sector Needs This qualification allows learners to demonstrate competence against National Occupational Standards which are based on the needs of the Construction and the Built Environment

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industry as defined by Construction Skills, the Sector Skills Council. As such it contributes to the development of skilled labor in the sector.

Potential Job Roles for Those Working Towards This Qualification Supervisor or lead in Sustainable Construction. Progression Opportunities This qualification allows learners to demonstrate competence in Thin Joint Skills and sustainable construction skills. The candidate can then move forwards with more formal qualification suites associated with awarding bodies. The course would support learners CPD. This would benefit company strategy and sustainability within the industry. The course would enable learners to access L4 and L5 courses in Sustainable Construction alongside a recognized route of RPL for L6 Site management or L4 Occupational Work Supervision. Delivery Methodology The session can be delivered in the work or classroom environment and uses a range of delivery techniques to impart information on the subject of Modern Construction Methods. Learning is assessed through formative checks and by using a summative site diary method to demonstrate competence.

Grading and Assessment The overall grade for the qualification is a ‘pass’. The learner must achieve all the required units within the specified qualification structure. To pass a unit the learner must:

achieve all the specified learning outcomes satisfy all the assessment criteria by providing sufficient and valid evidence for each criterion Show that the evidence is their own.

The qualification is designed to be assessed: In the workplace or In conditions resembling the workplace, as specified in the Assessment Strategy for

the sector, or As part of a training programme.

Assessment Strategy Evidence of competence may come from: Current practice where evidence is generated from a current job role A programmer of development where evidence comes from assessment opportunities built into a learning/training programmer whether at or away from the workplace. The Recognition of Prior Learning (RPL) where a learner can demonstrate that they can meet the assessment criteria within a unit through knowledge, understanding or skills they already possess without undertaking a course of learning. They must submit sufficient, reliable and valid evidence for internal and standards verification purposes. RPL is acceptable for accrediting a unit, several units or a whole qualification. To successfully achieve a unit the learner must gather evidence which shows that they have met the required standard in the assessment criteria. Evidence can take a variety of different forms including the following examples:

Direct observation of the learner’s performance by their assessor (O) Outcomes from oral or written questioning (Q&A) Products of the learner’s work (P)

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Personal statements and/or reflective accounts (RA) Outcomes from simulation, where permitted by the Assessment Strategy (S) Professional discussion (PD) Assignment, project/case studies (A) Authentic statements/witness testimony (WT) Expert witness testimony (EPW) Evidence of Recognition of Prior Learning (RPL).

To complement, and ensure progression in all areas of learning the following strategy will be used to complement the differentiation used in lesson planning after the process of Initial Assessment. These include:

Sessions on study skills, using libraries and using ILT in their programmers; Planning regular sessions with teachers of other areas of specialism and literacy,

language, numeracy and ICT specialists; Using teaching materials which use language at an appropriate level; Planning the use of clear language in giving instructions, both spoken and written; Developing or contributing to the development of activities that promote literacy,

language, numeracy and ICT learning alongside other skills.

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Course Materials

Scheme of Work

Course Title: Intro to Thin Joint Masonry and Sustainable Construction

Course Code: Start Date: No. of sessions: 2 GLH – 40 (14 hours classroom, 26 hours independent research activity)

Venue: Teacher: End Date: Time: 9am – 5pm

In the scheme of work identity how and when you will promote and embed: Equality and diversity E&D Health and safety H&S Safeguarding S

Maths embedded M English embedded E ICT embedded IT

Lifelong learning LL Prevent P British Values BV

Week: 1

Date & Duration:

Topic Teaching and Learning Strategies

Underpinning Skills Assessment Resources

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Day 1 Intro to Thin Joint Masonry and Sustainable Construction

Introduce learners to the topic of Thin Joint Masonry and Sustainable construction.

1. Tutor to introduce the concept of sustainable construction

2. Use group work to establish knowledge.

https://www.bre.co.uk/filelibrary/rpts/sustainable_construction_simpleways_to_make_it_happen.pdf

Tutor introduction.

Tutor to introduce and focus on the two headline terms.

1. Learners to work in groups to define the term “sustainable construction”

2. Learners to make notes and use group discussion to stablish the main points associated with Thin Joint Construction.

3. Learners to evaluate and produce reasoning around the use of Thin Joint Construction.

Learners to make notes and listen to introduction.

Produce a definition and underpinning explanation of sustainable construction.

Learners to make notes on Thin Joint systems.

Learners to work in groups and produce an evaluation to “present” the case for using Thin Joint systems.

Use of

Pen

Paper

Phone/Tablet research

Use of laptop research

Use of PPT pres.

Handouts

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Introduce learners to theory and procedures involved in Thin Joint Masonry.

Learners to listen and make notes from tutor lecture on Thin Joint Masonry.

Tutor to introduce theory of why?

Tutor to introduce materials

Tutor to introduce methods

Learners to produce theory pack of information from tutor lecture.

Use of

Pen

Paper



Use of PPT pres.

Handouts


The benefits of thin joint masonry and evaluation against other materials.

Tutor to introduce manufacturer’s material and specification information for a range of materials.

Tutor to introduce the concept of K values and the concept of carbon footprint reduction, against the perimeters of material and labour.

Learners to use information to evaluate best practice and materials.

Use of

Pen

Paper



Use of PPT pres.

Handouts

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Site Health and Safety and its links to thin joint masonry and modern construction methods.

Tutor to initiate learners into groups to complete Health & safety fact “thought cloud”

Learners to discuss how new methods and materials can effect site Health and Safety.

Learners to produce a checklist of documents which are commonly used and apply the principles of Thin joint masonry and sustainable construction them.

Learner list of required documentation

Learner research into documents used on site and what they are used for,

Use of

Pen

Paper



Use of PPT pres.

Handouts


Case studies and production of evaluation of process and materials.

Learners to use information and case studies to produce an evaluation of a material and a process.

The evaluation should include a study of materials preferred. A study of the process. It should also evaluate the material and process against the up to date requirements of sustainable construction and health and safety requirements.

Learner completion of evaluation and case study of materials and process associated with Thin Joint Masonry.

Use of

Pen

Paper



Use of PPT pres.

Handouts

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Lesson Plans

Course Title Introduction to Thin Joint Masonry and Sustainable Construction

Venue

Session 1234

Start Time 9am

End Time 5pm

Tutor

Date OTL N/A

Learning Aim: To prepare knowledge and procedure for Learning Outcomes:

1. Understand the process involved in site management 2. Identify the legislation and documentation that is used in site management 3. Identify health and safety procedures

Session Planning: Embedding Equality and Diversity (E&D) Embedding maths and English (E) (M) Safe Environment (S) Mapping:

Information Learning Technology (ILT) Health & Safety (H&S) British Values (BV) Prevent (P) Tutorial time with learners

Time

Tutor Activity Learner Activity Learning Outcomes

Mapping Resources

Assessment Method

E&D, E, M H&S, S, ILT, BV, P

09:00- 09:15

Lead Welcome and Introductions

Listening and Ice breaker

Introduce learners to tutor, building and each other Inc. H&S Policy and Fire Procedure

Learner Paperwork

Q&A H&S E

09:15-09:30

Outline of Course and Learning Outcomes

Listening and Questions

Introduce learners to course content

Power Point Q&A E

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Time


Mapping Resources

Assessment Method


Day 1 09:30-10:00

Introduce today’s session What is Thin Joint Masonry?

Paired / group Activity and Feedback to wider group

Define Thin Joint System & evaluate the Term Sustainable Construction. Produce list of considerations related to Thin Joint Systems Why? What Materials? Who does this?

Power Point Flip Chart & Pens https://www.bre.co.uk/filelibrary/rpts/sustainable_construction_simpleways_to_make_it_happen.pdf

Feedback Use research online for sustainable construction and U values

M

10:00-10:30

Introduce types of thin joint masonry Use PPT and handouts

Individual note taking

List and make notes List types List material types List tools

Power Point Paper Pens

Each learner makes own notes in workbook List and present to peers

E&D, S, BV, P M E

Break

10:50-11:15 11:15-12:00

Introduce ways Thin Joint masonry is used Introduce manufacturers materials Link to sustainable


Learners to make notes and take part in group thought cloud production Work in groups on compiling information on manufacturers product

Power Point & Video Handouts

Learner questions and discussion Compile facts on various products

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Time


Mapping Resources

Assessment Method


construction by tutor.

Lunch

13:00-15:00

Explain and discuss the benefits of Thin Joint masonry Show videos and case studies

Paired research and use of case studies and videos

Creation of method statement to include reasoning and rational for the use of MMM Present information on case studies in groups.

Case Studies Power Point Pen and Paper

Self and Peer Assessment of own practices against national standards

ILT E M BV –

15:00-15:30

Recap on learning aims

In groups test each table on materials and processes (can create quiz or gapped handout)

Produce quiz or gapped handout on Thin Joint masonry chosen subject.

Case Studies Power Point Pen and Paper

Peer assessment

15:30 end

Day 2 09:00-09:30

Introduce today’s session into Site Health and Safety and its links to thin joint masonry and

List known documents required on a construction site

Learner list of required documentation Learner research into documents used on site and what they are used for.

Power Point Flip Chart & Pens

Feedback M

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Time


Mapping Resources

Assessment Method


modern construction methods.

09:30-10:00

Tutor to introduce story on poor health and safety practices

Learners to discuss experience on site and share poor health and safety

Learners use personal experience to highlight potential health and safety risks in completing Thin Joint masonry procedures.

10:00-10:30

The documentation process

Individual note taking

Learner to make own document list and produce example documents

Power Point Paper Pens

Each learner makes own notes in workbook

E&D, S, BV, P M E

Break

10:50-11:15

Discuss findings as a group


Learners to make notes and take part in group thought cloud production. This to be transferred into producing a method statement

Power Point & Video Paper / pen

Learner questions and discussion Production of site diary

BV – rule of law

11:15-12:00

Using Case studies discuss compiling lists of tools and materials. Discuss the use


Learners to complete individual lists and method statements for case studies and evaluation of materials and process.

Power Point Case studies

Q&A Production of method statements

ILT E M BV – Democracy and Freedom

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Time


Mapping Resources

Assessment Method


of method statements.

Lunch

13:00-15:00

Continuation of method statement exercise


Learners to complete individual lists and method statements for case studies.

Q&A Production of method statements

15:00-15:30

Recap of learning and introduce learners to end assessment of completing and producing their own site diary of using Modern Masonry Methods.

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Course Resources

Baseline Assessment and Evaluation

Introduction to Thin Joint Masonry & Sustainable Construction

On a scale of 1-10 please mark with an X how true you feel each statement is to you.

1. I am familiar with the general principles behind Carbon reduction in construction.

1 2 3 4 5 6 7 8 9 10

Not at all True Fairly True Very True

Any Additional Comments:

2. I understand the benefits of using a range of materials to reduce carbon footprint.

1 2 3 4 5 6 7 8 9 10



3. I am familiar with the materials and method used in Thin Joint Masonry. 1 2 3 4 5 6 7 8 9 10



4. I am familiar with the components used in Thin Joint Masonry Construction. 1 2 3 4 5 6 7 8 9 10


Any Additional Comme

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5. I have an understanding of the different tools used in Thin Joint Masonry Construction.

1 2 3 4 5 6 7 8 9 10



6. I feel confident that I can produce a method statement for construction projects using Thin Joint Masonry.

1 2 3 4 5 6 7 8 9 10



7. I feel confident that I can use the processes described within the course to produce Thin Joint Masonry.

1 2 3 4 5 6 7 8 9 10



END OF COURSE EVALUATION

1. How useful was this course to you?

2. What could have been left out or included?

3. Any Other Comments. Your Name ___________________________________ Date ________________

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The Push to reduce Carbon in Construction

Sustainable materials One of the biggest impacts we can have on CO2 emissions is choosing less polluting materials. Cement production is responsible for around half of the industry’s CO2 output, both through the energy required to make it and the CO2 given off as a by-product of the chemical reactions involved.

Alternative cements are available which contain different chemicals which make them less energy-intensive to produce. Low-carbon cements generally incorporate magnesia, which means they actually absorb carbon dioxide from the atmosphere as they set.

Another approach is to increase the use of sustainable materials such as wood, straw bales and compressed soil which have a much lower carbon footprint than any sort of cement. Wood, straw and other grown materials also have the advantage of absorbing CO2 as they grow, reducing their environmental impact further.

https://www.bre.co.uk/filelibrary/rpts/sustainable_construction_simpleways_to_make_it_happen.pdf

Waste management Cutting waste is a really important strategy for cutting carbon emissions and can also save builders money. The main strategies for this are known as the three Rs of waste management – reduce, reuse, recycle.

Over-ordering is one of the biggest generators of construction waste, so reducing the amount of excess materials you buy in can cut your waste and your costs. The key here is to have really accurate estimates of the materials you need and avoid over-ordering ‘just to be on the safe side’.

When stripping out or demolishing an old building, it makes sense to recycle whatever you can. That way you cut the amount of materials you send to landfill and can usually generate some revenue by selling off anything of value. It is well worth taking a careful look around the site before you begin work, allowing you to identify anything worth reusing so this can be taken out first to avoid damage.

Anything which can’t be reused should be recycled if at all possible. Old stone and concrete can be crushed up for aggregate, while metal fixtures and wiring can often be melted down and reused. For information and advice on recycling construction materials contact the Waste and Resource Action Program (WRAP).

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Transportation At the moment, around 20% of the UK’s carbon dioxide emissions come from transportation. The construction industry could decrease its contribution to this figure in several ways. Firstly, you can switch to more efficient vehicles which produce fewer emissions per mile. Secondly, you can try to source materials locally as much as possible to reduce the distance over which they must be transported. Thirdly, you can select materials that weigh less or that can be packed more efficiently, reducing the number of journeys needed and cutting the amount of fuel used in their transport.

It is also worth checking with suppliers to see if they offer environmentally-friendly packaging and making sure you send pack pallets and other transport materials wherever possible. Wherever possible, it also makes sense to order as many of your materials as you can in one go from the same supplier, allowing you to reduce the number of partially full delivery vehicles going back and forth from your site.

Eco friendly buildings are on the rise in the UK, and pressure is mounting to build in a more environmentally friendly way – so are we reaching our goal? The number of eco-friendly construction companies is growing, and those who haven’t started using these methods may fall behind the times.

One of the main ways to become more environmentally friends is by using better insulation. The best ones, made from recycled material, reduce energy waste and have a low environmental impact. Buildings need to ensure that their hot water, heating, lighting and cooling systems all meet energy efficient measures. Windows, doors, vents and roof lights also need to be draught proofed.

Sustainable materials are also crucial. Cement production is responsible for around half of the industry’s CO2 output because of the energy required to make it, and the chemical reactions that are involved. Choosing an alternative cement that has different chemicals or use different methods such as wood, straw bales and compressed soil, have a much lower carbon footprint than cement.

The old adage of reduce, reuse, recycle is an important message with regards to reducing waste. Making sure that materials are not over ordered and recycling where ever possible is key. Sourcing materials locally is also a plus, because it means that there is less need for transporting them, and using materials that can be packed more efficiently and weigh less mean that energy is saved.

Optimising natural light and using solar power can be a great energy saver. Lighting can account for up to 40% of the energy used in a typical commercial building so making savings here seems obvious.

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Water usage can also make savings. Efficient fixtures and appliances can reduce water usage. Reduced flush toilets and rain water harvesting are becoming more popular as people seek to reduce their costs as much as possible.

Passive houses are also becoming more prominent. Passive house is a rigorous, voluntary standard for energy efficiency in a building, reducing its ecological footprint. It results in ultra-low energy buildings that require little energy for space heating or cooling. Passive House is not a brand name, but a construction concept that can be applied by anyone and that has stood the test of practice.

Carbon reduction is a complex challenge, and companies that can demonstrate green credentials are at the top of the construction sector in the UK. Managing and reducing the carbon footprint is becoming increasingly important in such a fast paced industry as ours.

Will take a look at the application and use of a material and process which reduces the carbon output of construction processes. That process is Thin Joint Masonry.

Thin Joint Introduction Whatever kind of building project you’re working on, you’ll want to give considerable thought to the materials that go into your scheme. Masonry is still the UK’s most popular construction system, thanks in no small part to the sense of solidity and familiarity it can lend to a home. But brick and block isn’t all about tradition – modern techniques and materials mean this structural route continues to be an attractive option for self-builders and renovators. Thin joint is one of the leading players, offering numerous benefits in terms of speed and efficiency that could make it the ideal choice for your project. Thin Joint Basics One of the biggest developments in modern masonry construction was the invention of air Crete blocks in the 1920s (although they weren’t widely used in the UK until the 1960s). These lightweight aerated products offer an appealing alternative to dense units. They’re easier to handle, quicker to build with and yield better insulation levels – something that’s particularly crucial as we move towards ever-lower carbon emission targets for new homes. Thin joint accentuates the advantages of air Crete by maximizing the potential of these precisely-manufactured blocks. The system uses a special cement-based, quick-set adhesive that’s just 2mm-3mm thick (as opposed to the standard 10mm mortar beds). This is delivered in 25kg powder bags, so your trades simply add water, mix in a bucket with an electric stirrer and spread the adhesive using a proprietary applicator. The lean bedding layer helps to ensure a faster build and also cuts down heat loss – as there’s simply less potential for air leakage through the joins. In fact, air Crete and thin joint are perfect partners, as the blocks are accurately dimensioned to the tightest possible tolerance (known as Thin Layer Mortar B). The foundations and first course above the DPC (damp proof course) should be bedded in standard mortar to achieve a level base for the work. After this, your contractor can build up the structure quickly, easily and with confidence that the remaining courses will be square

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thanks to the precision-engineered blocks. The thin joint system can be used for cavity, solid and party walls, as well as internal partitions. One alternative to the standard blocks is large-format air Crete panels – H+H Celcon offers a Multi Plate unit that’s 610mm (W) x 375mm (H) – which can cut down build times even further. And if you’re not keen on cement, clay versions such as Wienerberger’s Porotherm offer similar benefits – although concrete blocks are much greener than they once were. “UK aircrete manufacturers generally use at least 80% recycled materials that would otherwise be headed for landfill,” says Tom Somerville, in-house architect at Design & Materials. A Speedy Project Thin joint’s slender mortar layer reaches close to full bonding strength in just 15-20 minutes. This allows walls to be raised to story height in as little as a day on small self builds and extensions – so you can shave plenty of time (and labor) off a traditional blockwork build. “Around 25-30% of our clients go for thin joint construction,” says Tom. “Typically it knocks a few weeks off the total build time compared to using 10mm masonry beds – and the shell of a dwelling can go up just as fast as with timber frame.” That’s basically because you’re combing zero lead-time products with a quick, easy-to-use structural technique. “Once planning is approved and the groundworks are completed, your builder can start on site. There’s no waiting for the design and manufacture of a timber frame, which gives masonry a few weeks’ head start,” says Tom. The speed and strength with which the air Crete units adhere can also allow for a variation on the traditional brick and block programmer. Some self-builders choose the standard route of laying the inner and outer skins of a cavity wall simultaneously for their thin joint structures. But it’s also possible to complete just the inner leaf and get the roof on – getting you to weather tight stage much sooner. Features of a Thin Joint System Thin joint systems and by representatives of the industry have concluded that the benefits of the system are invaluable to an industry where clients, developers and external agencies continue to demand improved quality of the end product, at the same time as increased production. Benefits of the thin joint system The thin joint method uses a combination of lightweight Air Crete blocks and a fine sand- and cement-based, quick drying mortar. The main benefits of using the thin joint system include:

Speed Improved quality of the finished product. Speed Blockwork structures can be

constructed much more quickly than traditional methods. This is due to a number of factors.

The quick bonding time of the mortar reduces the swimming effect caused by the weight of the blockwork on the courses below.

The accuracy and uniformity of the Air Crete blocks, combined with the accuracy of the thin joint, reduces the time spent on levelling individual blocks.

With less mortar being used, the bond strength of the blockwork is enhanced. This again allows for more stability during the construction process and also allows other

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aspects of the construction work to continue within a short space of time, after the blockwork structure has been completed.

The thin joint system enables the inner leaf of a cavity wall structure to be built, in its entirety, prior to the outer leaf being built. This makes it possible to provide a waterproof work environment for other trades to carry on with the work programmer.

The availability of larger format blocks also increases the speed at which walls can be built.

Air Crete – a product name for blocks manufactured from autoclaved aerated concrete Key term

Swimming effect – this is where the blocks that have been laid float on the wet mortar bed as the weight upon them increases. This dramatically affects the setting time of the blockwork structure and restricts the height to which blocks can be laid in any one day Key term

Improved quality of the finished product The quality of the finished product is improved due to a number of factors. Air Crete blocks are produced to very accurate sizes, resulting in the finished product

having a cleaner and more uniform appearance. As the inner leaf of cavity structures can be built first, it is easier to maintain a clean

cavity and avoid the bridging of wall ties with mortar. The thermal insulation properties of the structure are improved because the mortar

joints are thinner and the area of blockwork is greater. Where larger format blocks are used, even better thermal insulation is achieved.

Air Crete blocks have high sound insulation properties due to the material used and the structure of the block.

There is less wastage of materials due to the ease and accuracy with which the blocks can be cut. Also thin joint mortar is supplied pre-mixed in 25 kg bags, allowing for just the right amount to be mixed for the job in hand, as and when required.

Resources Required Resources required to carry out the thin joint construction process: Air Crete blocks. These are made from autoclaved aerated concrete. This is a lightweight material which makes the blocks easy to handle and to cut, but at the same time has a high compressive strength. The main ingredients combined to form this material are lime, sand of quartz, water and cement. As the name suggests, Air Crete also contains between 60 and 80 per cent of air by volume, with thousands of tiny air bubbles being produced during the ‘baking’ process. Once this process is complete and the material has been allowed to set, it is cut into blocks of the required size using mechanical wires. In order to obtain the maximum strength of the blocks, they are cured in autoclaves. This is where the blocks are subjected to saturation with high pressured steam at temperatures up to 200°C. Air Crete blocks are available in a variety of sizes ranging from the standard sized block of 440 mm × 215 mm up to an extra-large block with a face size of approximately 610 mm × 270 mm. These blocks are also available in varying thicknesses and grades to suit the work being carried out. As there is less mortar used with the thin joint system, more blocks will need to be ordered per meter squared, when estimating for a project using a standard sized block. Remember ‘U’ values – these indicate the thermal performance of a material in different situations

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Key Term Data on fire resistance, ‘U’ values and handling weights of various types of Air Crete blocks can be obtained from the various manufacturers using their technical helplines. Did you know? Thin joint mortar It is formed from a number of resources:

sand cement water plasticizers (for brickwork) Coloring agents (where colored mortar is desired).

Mixing Processes It usually requires mixing, either by hand or machine, although certain mortar products can be purchased pre-mixed and ready for use. Thin joint mortar is a combination of fine ground sand (silica) and Portland cements. It is available under a number of different trade names and is produced by various manufacturers as part of their thin joint systems. It is normally supplied in 25 kg bags and then added to water and mixed until the correct consistency is obtained. Guidance for mixing is given on the packaging. Thin joint mortar remains workable for a number of hours – up to four hours in most instances – while still in the bucket. However, once spread on the block, the mortar will begin to set within 10 to 20 minutes. Full setting of the mortar is reached after approximately 1 to 2 hours, depending on the product. Thin joint mortar is spread at a thickness of 2–3 mm. The tools used for the mixing and application of the mortar are explained later in this unit. Machine mixing by machine can be carried out by using an electric, petrol or diesel mixer. Always set the mixer on level ground. Fill the mixer with approximately half of the water recommended, adding the plasticizer if it is being used. Add half of the cement and half of the sand required to the water. Allow them to mix and then add the remaining cement, then the sand. Add more water if required, allowing at least two minutes for the mix to become workable and to ensure that all the materials are thoroughly mixed together. Once the mix has been taken out of the mixer, part fill the mixer with water and allow the water to run for a couple of minutes to remove any mortar stuck to the sides. It is recommended that you use suitable hand protection when using thin joint mortar. As this type of mortar is cement-based, there is a risk of developing dermatitis and/or burns and irritation to the skin through prolonged exposure to it Safety tip. Always clean the mixer thoroughly after use, using either water or ballast and gravel to prevent future material from sticking to the drum sides so easily. Movement Ties and Joining

Wall Ties for Thin Joint Systems Wall ties used in traditional brick and block structures are not suitable for use in thin joint systems as they are too thick to fit into the thin mortar joints. However, there are a variety of ties compatible with thin joints currently on the market. The majority of them are made from stainless steel. Some of the most common include:

Twist ties Flat steel ties

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Abutment wall ties Movement joint ties.

Twist Ties These are used for cavity walls where the inner leaf has been built and the outer leaf is still under construction. They are driven into the Air Crete block work at a height to suit the outer leaf courses as they are laid. These ties will also take insulation clips, which secure partial fill cavity insulation batts. Twist ties are available in various sizes to suit up to 150 mm cavities.

Flat Steel Ties They are available for use when joining the inner and outer leaves of a cavity wall where the two leaves which are constructed at the same time and are of the same course height. The ties are bedded into the blockwork in the same way as traditional methods. Flat steel ties are also available for connecting blockwork at junctions, where perimeter walls join partition or dividing walls. Abutment Wall Ties These are also used for connecting blockwork at junctions where courses are not at the same level. The tie is fixed to the perimeter wall using a suitable fixing and the other end of the tie sits into the bed joint of the adjoining wall. Movement Joint Ties As the name suggests, these are used to tie walls together where the continuous length has been broken up to allow for movement joints. They allow for contraction and expansion between the two walls to avoid any damage to the blockwork caused by movement. Tools Needed for Thin Joint System Scoop - This is used to spread thin joint mortar, producing a consistent joint thickness of 2–3 mm. The scoop is available in varying sizes of between 75 and 200 mm. Sledge As with the scoop, this tool is also used to spread thin joint mortar. However, the sledge is for use where the width of the block exceeds 200 mm. This tool is available in sizes between 200 and 300 mm.

Masonry hand saw – this is used to cut Air Crete blocks to the required size. Block cutting square. This is used as a marking guide when cutting blocks. Sanding board – the sanding board is used to remove any imperfections in the bed course. As the thin joint system requires a very accurate bed thickness to be maintained, it is important that any raised areas in the bed course are removed prior to applying the thin mortar joint. Block rasp – the block rasp is used to trim any areas of the block that are raised and too big to be removed with a sanding board. These raised areas may occur when there has been inaccurate cutting and will affect the accuracy of the thin joint thickness. On large sites, or in instances where a large number of cuts are required for the job, a mechanical hand saw or circular saw may be used to cut blocks Remember Whisk attachment – the whisk is attached to a powered drill and is used to mix the thin joint mortar in a large tub or bucket. Bonding for blockwork. Blockwork should be set out to use as many full blocks as possible. At an internal corner, a 100 mm section of block should be used to gain half bond. Never use

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brick on an internal corner, as the thermal value of a brick is not to the same as a block and will cause a ‘cold spot’ to the finished area, possibly showing through the plaster on completion. Damp proof barriers. The techniques used for this are the same as for cavity walls. Cutting Components When preparing to build walls, you may need to cut and prepare blocks.

There are three different methods that can be used:

By hand using a hammer and bolster chisel by hand using a saw

By machine using a portable disc cutter or fixed table saw. The method used sometimes depends on the type of block being used. A hand saw would be no good to cut concrete blocks, but perfect for lightweight blocks.

A hammer and bolster are adequate for concrete blocks, but can chip the edges of the cut. If the cut blocks are to be covered by another material, this would be acceptable, but if the blocks have a face finish, then machine cutting would be the better option, especially if a large number of cuts are required.

Protecting materials and completed work After completing a day’s work, the bricklayer must take precautions to prevent damage to the wall from the weather. Rain will cause mortar joints to run over the face of the wall, causing unsightly stains. To prevent rain damage, walls should be covered with a polythene sheet or tarpaulin. A scaffold board or bricks can be used to secure the cover in place. The sheeting should be kept clear of the wall to allow for ventilation. Cold weather could cause the water in the mortar to freeze, damaging the bonds between blocks and bricks, making the wall weak and possibly causing the wall to be taken down. To prevent the mortar from freezing, newly built walls should be covered if there is a sudden drop in temperature to below 3ºC. The covering should consist of a layer of hessian or insulation slabs, with a waterproof tarpaulin or plastic sheeting on top. Maintaining industrial standards Industrial standards are the standards and tolerances allowed on site, or in the workshop, covering the plumb-ness, level and finish of a wall, if it is to gauge, if the joints on courses run true and plumb, as well as the cleanliness of the wall once built.

Working with Materials

Positioning Materials Before beginning construction work, you will need to position and stack the components you need to work with on the construction site. Each site will have different rules for arranging materials, either placing them nearby or keeping them in a holding compound until needed. There may be written instructions for storing and placing materials, or you may be given verbal instructions by a site manager. In both cases, it is important to check any information you find confusing and to confirm that you have understood how materials are to be placed. Decisions on material placement affect everyone on site, as everyone needs to know how to access them. Placing materials in the wrong place could also lead to health and safety issues. It is essential that the bed course is level and free from imperfections prior to laying the first bed of the thin joint mortar. Remember: The standard block size is 440 mm x 215 mm. Remember Forms of construction where the thin joint system can be used.

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The structure and composition of Air Crete blocks make them a very versatile material. When they are used in conjunction with the thin joint mortars that are now available, the thin joint system becomes suitable for most aspects of construction normally associated with the more traditional types of materials. The thin joint system can be used for any of the following:

Foundations Partition walling External solid walling Cavity walling

Separating or Party Walls As the thin joint system has high resistance to both water penetration and frost, few problems are encountered when it is used for external solid walling. However, it is recommended that the external face of the blockwork is finished with either cladding or a traditional rendered finish, particularly where the wall is constantly exposed to inclement weather, such as rain and frost. The thin joint system also has a high resistance to fire and good sound insulation qualities, making it highly suitable for the construction of partition walling and separating walls. The strength and sulphate resistant properties of the system, also make it suitable for foundation walls in most types of soil and ground conditions. Methods of Construction Using the Thin Joint System If constructing a cavity wall structure, it is important to ensure that the substructure walls are built up to the damp proof course (DPC) prior to laying the inner thin joint blockwork. This enables any required openings to be set out accurately before work starts on the superstructure. You must always ensure that the course that is to receive a bed of thin joint mortar is free from dust as this can adversely affect the adhesion of the mortar. In most cases the first course or ‘bed course’ in the thin joint system should be laid using the normal sand/cement mortar. This will take out any inaccuracies that are present within the floor slab or foundation masonry. In order to maintain accuracy in the courses above the bed course, thin joint mortar may be used for the perps (vertical joints) of the bed course. Once the bed course is sufficiently stable, work with the thin joint system can commence. Bonding arrangements and the installation methods are much the same as the traditional block laying methods. When erecting the corners of block walls built using the thin joint system, it is vitally important to ensure accuracy in the levelling, plumbing and gauging of the blocks. With the thin joint system there is no option of opening up joints to compensate for inaccuracies you might have caused during the build. Once the corners have been erected, the blocks can be run into a line as normal. The thin joint mortar is applied to the blocks using a scoop or a sledge depending on the width of the block. Both tools provide a consistent 2–3 mm layer of mortar across the bed and vertical joints. As the individual blocks are laid, they should be firmly pushed against the vertical, mortared face of the previously laid block and at the same time lowered onto the mortared bed below. It is important to ensure that full joints are maintained at all times to retain the effectiveness and stability of the thin joint system. Where there is a need to tap blocks into place to ensure full uniform joints that are accurately laid to the line, a rubber mallet should be used in order to prevent damage to the blocks. As previously stated, when constructing cavity walls, the inner leaf can be built in its entirety prior to work commencing on the outer leaf. Assessment

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1. Preparation for Evaluation. 1. Explain what a block rasp is used for. 2. Draw a sketch of a movement tie. What is this tie used for? 3. Draw a section of a box type lintel in place. Prepare a method statement showing how you put this in place. What other tasks would need to /be carried out before you could install this lintel? 4. Draw a sketch of a Pistol brick and explain where it would be used in construction. 6. Describe the advantages it has over other types of brick. 7. Explain how Aircrete blocks are made. Prepare a table showing the difference between air Crete blocks and other types of block. 8. Explain what swimming means. Prepare a method statement explaining how you could avoid swimming from happening. 9. Sketch a diagram of a floor slab, incorporating an edge beam. Describe how this is assembled and the benefits it brings to a building. 10. Name three types of ties used in thin joint masonry. 11. Why are these ties used at different points? Explain why you would choose a particular tie. 2. Evaluation of method Evaluate the procedure and method for using Thin Joint Masonry on your construction site. Produce a balanced argument to use or not use the method stating your reasons. This cannot be purely based on method. Your argument must also be based on its relevance to construction carbon reduction and energy saving techniques in construction. Completing Practical Assessment of process and evaluation of method and materials. You will need to be familiar with: This unit has shown the reasons for using, and methods of using, thin joint masonry. You have seen how to construct masonry for use with concrete- and steel-framed buildings to required specifications. This qualification has shown the importance of putting together a checklist of resources and explained the methods of construction and cutting components. You will need to use this information to put together your own checklists, as well as selecting the method of construction and cutting of components that is most appropriate for your situation and the specifications. Producing a work method will be an important part of selecting the most appropriate method. You will need to construct walling to form straight lengths, return and junctions. This will need to be carried out safely and you will need to use your knowledge in your practical work to identify the safest way of working. Carrying out a risk assessment will be an important part of this. You need to produce a method statement and risk assessment for the complete system of works for using Thin Joint Masonry.

Course Resources

https://www.bre.co.uk/filelibrary/rpts/sustainable_construction_simpleways_to_make_it_happen.p

df

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Case Studies

http://www.masonryframesystems.co.uk/wp-content/uploads/2012/04/addlestone-case-study.pdf

http://www.masonryframesystems.co.uk/wp-content/uploads/2016/03/West-Way-Littlehampton-Case-Study.pdf

http://www.masonryframesystems.co.uk/wp-content/uploads/2012/04/ashford-case-study.pdf

Learner Activities for Case Studies In groups use the case studies to produce a material list, tool list and construction statement which highlights the positives of the type of construction used in each study. Explore the material and methods using online research to familiarise yourself with each method.

Learners should work in groups to evaluate the materials and processes used in the case studies. Groups should evaluate which method is the most successful across three areas of consideration.

1. Ease of method 2. Environmental Credentials 3. Cost

Handouts for Study

http://www.thomasarmstrong.co.uk/downloads/Thin%20Joint%20Brochure%20-%20October%202011.pdf

https://www.hhcelcon.co.uk/solutions/by-method/thin-joint-method

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PowerPoint Presentation

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introduction to thin joint masonry as a · introduction to thin joint masonry & sustainable...

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