godalming key site environmental … k...made to the british standard code of practice for...

November 2009

GODALMING KEY SITE

ENVIRONMENTAL STATEMENT

CHAPTER K:

SUNLIGHT/DAYLIGHT

CONTENTS

1.0 INTRODUCTION ............................................................................................................ 1

2.0 POLICY CONTEXT ........................................................................................................ 2

National Planning Policy ................................................................................................. 2 Local Planning Policy...................................................................................................... 2 BRE Guidelines............................................................................................................... 3 Daylight........................................................................................................................... 3 Sunlight........................................................................................................................... 4 Overshadowing ............................................................................................................... 5 British Standard BS8206 – Lighting for Buildings – Part 2: Code of Practice for Daylighting 2008 ............................................................................................................. 5

3.0 ASSESSMENT METHODOLOGY .................................................................................. 6

Assessment Methodology ............................................................................................... 6 Sunlight Adequacy to Existing Neighbouring Dwellings................................................... 7 Significance Criteria ........................................................................................................ 8

4.0 BASELINE CONDITIONS............................................................................................. 11

1-12 Wharf Street.......................................................................................................... 11 50-55 Catteshall Lane................................................................................................... 11 2-28 Victoria Road ........................................................................................................ 12

5.0 PREDICTED IMPACTS ................................................................................................ 13

Demolition and Construction ......................................................................................... 13 Completed Development............................................................................................... 13 1-12 Wharf Street.......................................................................................................... 13 50-55 Catteshall Lane................................................................................................... 14 2-28 Victoria Road ........................................................................................................ 15 Cumulative Impact ........................................................................................................ 17

6.0 EVALUATION OF SIGNIFICANCE .............................................................................. 18

7.0 OPPORTUNITIES FOR MITIGATION AND ENHANCEMENT ..................................... 19

8.0 RESIDUAL IMPACTS................................................................................................... 20

9.0 SUMMARY AND CONCLUSIONS................................................................................ 21

REFERENCES......................................................................................................................... 23

LIST OF APPENDICES K.1: Site Plan and 3D Massing Models, Drawing Numbers ROL5877_5_000, 001, 002 and 003. K.2: Daylight Distribution Contours, Drawing Numbers ROL5877_5_100, 101, 102 and 103. K.3: Vertical Sky Component Analysis Table. K.4: Daylight Distribution Analysis Table. K.5: Overshadowing Analysis Table. K.6: Overshadowing Analysis, Drawing Number ROL5877_5_200. K.7. Room Layout and Location Plans for Proposed New Dwellings and Average Daylight Factor

and Sunlight Tables. K.8. Permanent Overshadowing Analysis, Drawing Number ROL5877_5_305 and Table P6 LIST OF TABLES K.1: Vertical Sky Component Significance Criteria K.2: Daylight Distribution Significance Criteria

GODALMING KEY SITE PHASE II: ENVIRONMENTAL STATEMENT

Chapter K: Sunlight/Daylight 1

1.0 INTRODUCTION

1.1 This Chapter assesses the effects of the development with regard to sunlight and

daylight and overshadowing and has been written by Anstey Horne & Company

Limited.

1.2 The Chapter describes the methods used to assess the effects, the baseline daylight

and sunlight conditions currently existing at the site and the sensitive receptors that

are likely to be affected by the development.

1.3 The following potential effects of the development have been considered:

• Impact on daylight received by the existing neighbouring residential dwellings around the site.

• Impact on the sunlight received by the existing neighbouring residential dwellings around the site.

• Impact on the overshadowing of the designated garden areas of those dwelling houses adjacent to the site.

1.4 The proposed development is an entirely “new-build” development of dwellings, and

hence has no existing baseline conditions. An additional part of the assessment has

been to measure and verify the quality and adequacy of sunlight and daylight that will

be enjoyed by those proposed new dwellings. A representative sample of the

habitable rooms within the proposed new dwellings have therefore been tested for

daylight and sunlight and the proposed new amenity areas, especially the courtyards,

have been tested for the amount of permanent overshadowing in accordance with the

BRE Guidelines.



2.0 POLICY CONTEXT

National Planning Policy

2.1 There is no current specific national planning policy relating to development and its

potential impacts on daylight and sunlight. The only guidance at national level relates

to tall buildings in guidance produced by English Heritage/The Commission for

Architecture and the Built Environmental (CABE) which recommends that

consideration be given to:

“the effect on the local environment, including microclimates, overshadowing,

night time appearance, vehicle movement and the environment and those in

the vicinity of the building”.

2.2 The current proposals would not be classed as a “tall building” for the purpose of

National Planning Policy

Local Planning Policy

2.3 The relevant Local Plan covering this Application Site is the Waverley Borough

Council Local Plan which was adopted in 2002. Policy D1 states that the Council will

have regard to the environmental implications of development and that it will not be

permitted where it would result in material detriment to the environment by virtue of:

“(c) Loss of general amenity, including material loss of natural light and

privacy enjoyed by neighbours and disturbance resulting from the

emission of noise, light or vibration.”

2.4 Policy D4 (c) goes on to say that new development should:

“not significantly harm the amenities of occupiers of neighbouring properties by way

of overlooking, loss of daylight or sunlight, overbearing appearance or other adverse

environmental impacts.”



BRE Guidelines

2.5 To assess the likely impact objectively, the scientific empirical measurements

contained in the Building Research Establishment (BRE) Guidelines “Site Layout

Planning for Daylight and Sunlight – A Guide to Good Practice” 1991 are the

standards almost universally adopted by Planning Authorities. Reference is also

made to the British Standard Code of Practice for Daylighting, BS8206 Part 2 2008

and the CIBSE Applications Manual for Window Design, LG10.

2.6 Access to daylight in existing buildings has been assessed in accordance with the

methodology set out in Section 2.2 of the BRE Guidelines. The methodology for

sunlight has been taken from Section 3.2.

Daylight

2.7 The BRE Guidelines contain two methods for calculating daylight:

• The Vertical Sky Component (VSC) method.

• Internal Daylight Distribution by the use of the no skyline contour method.

2.8 The VSC method measures the amount of light available on the outside plane at the

centre of the window expressed as a percentage ratio of the amount of total

unobstructed sky visible following the introduction of visible barriers such as buildings,

in comparison to a totally unobstructed outlook. It is a “spot” measurement of daylight

at one given reference point and takes no account of the actual size and use of the

room and the window(s) serving that room.

2.9 The maximum VSC value achievable for a completely unobstructed outlook from a

conventional window in a vertical plane is approximately 40% VSC.

2.10 In its simplest form, VSC can be calculated by using the Skylight Indicator or

Waldram diagrams taken from the Appendices in the BRE Guidelines. These manual

methods do however contain inevitable margins of error and for the present

assessment, specialist daylight software has been used including a 3D massing

model built up from the survey drawings so as to provide a much higher degree of

accuracy.



2.11 The no skyline contour measures the internal Daylight Distribution within the room

being tested. It divides those areas within the room, measured usually at a horizontal

working plane of 850mm above finished floor level, which can receive direct light from

the sky, from those which cannot. It therefore illustrates the pattern and amount of

daylight penetration within the room being assessed.

Sunlight

2.12 The BRE Guidelines recommend that access to sunlight be assessed for

development proposals. Potential impact on available sunlight is assessed using the

BRE’s Annual Probable Sunlight Hours (APSH) method. This method involves the

prediction of sunlight availability for the main window of each habitable room where

that window faces within 90 degrees of due south. Sunlight availability is measured

for the total year and separately for the winter months. The winter analysis covers the

period between the autumn equinox (21st September) and the spring equinox (21st

March) with the summer period covering the remaining months. The test date for

sunlight is the spring equinox of 21st March on which date the United Kingdom

receives 12 hours of daylight and 12 hours of darkness with sunlight availability

generally being limited to between 0700 and 1700. On that date, sunlight is only

directly incident perpendicular to the plane of a window where that window faces

within 90 degrees of due south. The key receptor for sunlight in a dwelling is the

principal living room.

2.13 For the availability of daylight to existing neighbouring dwellings, the Guidelines

require the measurement of Vertical Sky Component (VSC) which measures the

amount of natural daylight striking the face of the window, followed by the

measurement and plotting of a “no skyline” contour within the room in order to

measure internal Daylight Distribution.

2.14 For sunlight, the Guidelines require the measurement of the total amount of sunlight

received by a window facing within 90 degrees of due south measured on the spring

equinox together with the separate measurement of the availability of winter sunlight.

2.15 For overshadowing, the Guidelines require the measurement of the amount of

permanent overshadowing on the ground measured on the spring equinox.



Overshadowing

2.16 The BRE overshadowing criteria should be applied to garden areas and designated

amenity spaces such as children’s playgrounds and sitting out areas.

2.17 It measures the amount of permanent overshadowing on the surface of the ground.

For a garden or amenity area to appear to be adequately sunlit, no more than two

fifths and preferably no more than a quarter of that garden or amenity area should be

prevented by buildings from receiving any sun at all on the spring equinox of 21st

March. If as a result of new development an existing garden or amenity area does

not meet these guidelines, and the area which can receive some sun on 21st March is

less than 0.8 times its former value, then the loss of sunlight is likely to be noticeable.

The maximum amount of permanent overshadowing of the proposed gardens should

therefore not exceed 40% but preferably a target of 25% should be achieved.

British Standard BS8206 – Lighting for Buildings – Part 2: Code of Practice for

Daylighting 2008

2.18 BS8206-2 provides guidance and target standards for the measurement and

assessment of daylight and sunlight adequacy within proposed new-build buildings.

The guidance and methodology in BS8206-2 is similar to the guidance and advice

contained in Appendix C of the BRE Guidelines but has been updated to include a

more detailed and representative methodology for measuring Average Daylight

Factors. The target standards for ADF have however remained unchanged and are

the same as those in the BRE Guidelines i.e.:

• Family kitchens – 2% df.

• Living rooms – 1.5% df.

• Bedrooms – 1% df.



3.0 ASSESSMENT METHODOLOGY

Assessment Methodology

3.1 Daylight and sunlight are two constituents of general “amenity”, the others being

overshadowing, sense of enclosure, privacy and overlooking. The impact on natural

daylight and sunlight to non-domestic and commercial premises is not considered to

be important unless that non-domestic use has a specific requirement for daylight as

part of its normal day to day operations. Suitable examples of where non-domestic

buildings should be included are school classrooms, hospital lying-in wards and

certain other forms of community or recreational buildings such as art galleries or

places of worship. Daylight and sunlight to commercial premises such as offices,

shops and warehouses are not considered to be essential for their use as it is

accepted practice that they usually operate under permanent supplementary artificial

lighting throughout the day. If they are considered at all, they would be classed as a

receptor with very low sensitivity.

3.2 For the purpose of assessing environmental impact, the sensitive receptors are

therefore limited to residential properties and in particular daylight and sunlight to

habitable rooms within those residential properties. A “habitable” room is defined as a

living room, kitchen or bedroom. Bathrooms, hallways and circulation space are

excluded. It is also generally accepted that a kitchen need only be classed as a

habitable room where it is large enough to accommodate an additional function apart

from food preparation such as dining or as a separate dayroom. For the purpose of

the Building Regulations and Environmental Health Standards, daylight is not a

requirement for a kitchen which is solely used for food preparation provided there is

adequate mechanical ventilation.

3.3 This is normally assessed on the basis of internal area in that for a kitchen to be

classed as a habitable room, the threshold internal area is usually set at 13m²

excluding fixtures and fittings. For example, it is perfectly acceptable to have internal

windowless kitchens provided that they satisfy the Building Regulations in terms of air

changes per hour through mechanical ventilation where a kitchen is solely used for

food preparation and not used as a separate habitable room.

3.4 This principle would also apply to the trend towards open plan living where the “living

room” part of the room is usually located adjacent to the window so as to enjoy the



benefit of daylight and sunlight whereas the kitchen area is seen as the subservient

use and usually located at the rear of the room where daylight and sunlight will be

very limited, if received at all.

3.5 Within dwellings, the key habitable room is the living room, which should be classed

as the main sensitive receptor for daylight, as it is the room most likely to be occupied

for the largest part of the day during daylight hours. Kitchens (where they are classed

as habitable rooms – see 3.2 and 3.3 above) are less important, and finally bedrooms

are the least sensitive receptor as they are generally unoccupied during daylight

hours.

Sunlight Adequacy to Existing Neighbouring Dwellings

3.6 For sunlight, the BRE Guidelines recommend that access to sunlight be assessed for

development proposals. Potential impact on available sunlight is assessed using the

BRE’s Annual Probable Sunlight Hours (APSH) method. This method involves the

prediction of sunlight availability for the main window of each habitable room where

that window faces within 90 degrees of due south. Sunlight availability is measured

for the total year and separately for the winter months. The winter analysis covers the

period between the autumn equinox (21st September) and the spring equinox (21st

March) with the summer period covering the remaining months. The test date for

sunlight is the spring equinox of 21st March on which date the United Kingdom

received 12 hours of daylight and 12 hours of darkness with sunlight availability

generally being limited to between 0700 and 1700. On that date, sunlight is only

directly incident perpendicular to the plane of a window where that window faces

within 90 degrees of due south. The key receptor for sunlight in a dwelling is the

principal living room. That room should therefore be treated as a sensitive receptor.

Kitchens and bedrooms are low receptors.

3.7 Each of the methods of measurement described above have been applied in this

assessment with calculations being undertaken using specialist computer software

applied to three dimensional autocad models of the existing surrounding properties

and the Proposed Development. The computer software is based on the Waldram

method to establish VSC, and uses the room layouts and window dimensions derived

from the accurate survey information produced by Michael Gallie & Partners Land

Surveyors supplemented by historical survey information supplied by Scott Wilson

Limited and Z-Mapping.



3.8 The existing surrounding buildings have been modelled using the site survey together

with research of the historical archives for as many of the neighbouring buildings as

possible. Where detailed drawings have not been available, floor heights and room

layouts have been estimated from window locations and the characteristics of the

buildings in question. The only existing designated amenity areas under present

conditions adjacent to the site which could fall within the BRE overshadowing criteria

are the rear gardens of 2-28 Victoria Road (even numbers).

Significance Criteria

3.9 The criteria given in the BRE Guidelines have been used as a basis to assess the

Proposed Development’s potential impact. The significance criteria for each of the

methods of measurement is summarised below.

3.10 The VSC method measures daylight in two ways:

• First, on an absolute scale based on the actual VSC value measured on the

face of the window being tested; and

• Second, on a comparative scale based on the light received expressed as a

percentage of the original value.

3.11 A Significance Criteria therefore needs to incorporate both scales of measurement.

3.12 To satisfy the initial test in the Guidelines, the Vertical Sky Component measured on

the face of the window should not fall below a target value of 27% VSC. Provided

that a window will continue to receive more than 27% VSC, it will receive an adequate

amount of daylight for all conventional habitable uses. It is however recognised that

this target standard has been derived using a low density suburban housing model

and that with existing buildings in a relatively densely built-up historic urban

environment, especially for windows in lightwells, the magnitude of such levels of

daylight is often unachievable. Where the VSC value is below 27% under existing

conditions, it becomes necessary to assess the percentage reduction. From the

research undertaken by the BRE, they have found that it is acceptable to reduce

existing daylight (and sunlight) levels by a factor of 0.2 (20%) before that loss of light

becomes materially noticeable.

3.13 The no skyline test is an area-based test and is measured in terms of a percentage

reduction in the amount of the working plane that has direct sky visibility. If, following



the construction of a new development, the no skyline contour moves so that the area

of the existing room that does not receive direct sky light is reduced by more than 0.2

(20%) times its former value, then this will be noticeable to the occupants and more of

the room will appear poorly lit.

3.14 The methods of testing and units of measurement for daylight (and sunlight) do not

lend themselves very easily to the ranking system adopted in the conventional

“Significance Criteria” generally followed in Environmental Statements, as they are

often used in a “pass” and “fail” manner rather than on a sliding ranking scale.

However, in the tables below, each table represents the Significance Criteria adopted

for each of the daylight methodologies.

Table K.1:Vertical Sky Component (VSC)

Quantitative Reduction Significance

VSC between 25% and 27% or loss less than 20% of present value.

Negligible

VSC between 20% and 24.99% or loss between 20% and 29.9% of present value.

Minor Adverse

VSC between 10% and 19.99% or loss between 30% and 39% of present value.

Moderate Adverse

VSC below 10% or loss greater than 40% of present value.

Substantial Adverse

Table K.2: Daylight Distribution

Quantitative Reduction Significance

Loss less then 20%. Negligible

Loss between 20% and 29.9%. Minor Adverse

Loss between 30% and 39.9%. Moderate Adverse

Loss over 40%. Substantial Adverse

3.15 For the measurement of daylight, sunlight and overshadowing of the proposed new

dwellings, as there are no existing baseline conditions, there can of course be no

measureable “impact” by measuring and comparing the difference between an

“existing” and “proposed” set of conditions. The significance criteria for the proposed

new dwellings and amenity areas should therefore be measured against the absolute

design standards contained within the BRE Guidelines and British Standard Code of



Practice for Daylighting. This will be assessed on a “pass” or “fail” basis and if any of

the sample Receptors do not meet the target design standards, the amount by which

they fail to meet that standard is then the material consideration in assessing

“impact”.



4.0 BASELINE CONDITIONS

4.1 The site is presently made up of several parts which vary in age, use and nature of

existing buildings ranging from a Police Station, occupied and derelict light industrial

units and areas of cleared land. There is no single coherent or uniform type or scale

of building on the site.

4.2 The site itself is approximately triangular in shape being bordered by Wharf Street to

the north west and Catteshall Lane along the south with the north eastern boundary

of the “triangle” being formed by the rear terrace houses at 2-28 Victoria Road and

the adjoining land owned by the Council (presently used as an open surface level car

park).

4.3 The sensitive receptors to daylight and sunlight are the windows serving habitable

rooms in the existing neighbouring residential properties.

4.4 A review of the site and its surroundings has identified the following sensitive

receptors:

• The dwellings in 1-12 Wharf Street.

• The habitable rooms in the dwelling houses in 50-55 Catteshall Lane.

• The habitable rooms in 2-28 Victoria Road (even numbers).

1-12 Wharf Street

4.5 This property appears to be a block of flats and lies adjacent to the western apex of

the triangular site at the junction of Wharf Street and Catteshall Lane. The principal

receptors, i.e. the front elevation windows, face south west and face onto Hambledon

House. Those windows do not have a direct outlook onto the Site but do receive

daylight and sunlight from an oblique angle and could therefore experience an impact.

50-55 Catteshall Lane

4.6 There is a considerable difference in finished ground level between the site and the

houses that we have identified as 50-55 Catteshall Lane. Those houses stand

considerably higher than the level of the site itself. Each house has a number of

north facing windows which have a direct outlook onto the site and those windows



appear to serve habitable rooms. They are therefore sensitive receptors in respect of

daylight. Sunlight does not apply to these properties as the windows do not face

within 90 degrees of due south and therefore do not fall within the BRE sunlight

criteria, nor will there be any overshadowing of the existing gardens that serve these

properties.

2-28 Victoria Road

4.7 These are a row of relatively small terraced houses with single storey rear extensions.

The terrace has a slight curve to the effect that some of the windows face within 90

degrees of due south and therefore fall within the BRE sunlight criteria.

4.8 At ground floor level, some of the windows have been enclosed by extensions to the

original rear extensions and where the ground floor rear facing windows have not

been enclosed, they suffer from the “tunnel effect” created by the pattern of

consecutive rear extensions side by side. This arrangement therefore prejudices the

availability of daylight and sunlight under baseline conditions and any future

conditions and the impact on these particular windows should therefore be taken in

this context.



5.0 PREDICTED IMPACTS

Demolition and Construction

5.1 The level of impact in relation to daylight and sunlight to the surrounding properties

will vary throughout the demolition and construction phases depending on the level of

obstruction caused. There will be a brief and temporary improvement in daylight

levels during the demolition phase when the existing buildings are demolished and

the site is cleared. However, as the existing and proposed buildings are constructed,

including the necessary Temporary Works that will be required such as scaffolding,

debris netting and site hoardings and other forms of Temporary Works, there will be a

temporary loss of daylight which will go beyond the impact of the completed building

as the temporary “massing” created by scaffolding and other temporary works will be

marginally larger than the completed building. Those temporary works are however

necessary for the construction of the development to some extent for Health & Safety

but as they will be in place for a relatively short period during the course of

construction their effect will be of negligible significance.

Completed Development

5.2 As the proposed new buildings are of greater “massing” in comparison to the existing

buildings, the levels of natural light received by the receptors in 1-12 Wharf Street,

50-55 Catteshall Lane and 2-28 Victoria Road will be reduced. Annexed at Appendix

K.1 is a copy of drawing numbers ROL5877_5_000, 001, 002 and 003 which

comprise the site plan and images of the 3D massing models of the existing and

proposed buildings. This is followed at Appendix K.2 by drawing numbers

ROL5877_5_100, 101, 102 and 103 which illustrate the Daylight Distribution no

skyline contour analysis for each of the sensitive receptors and also provide the

location references for the windows and rooms tested in the analysis. Those

references should be cross referenced with the room and window locations referred

to in the tabulated numerical results tables for the daylight and sunlight analyses

annexed at Appendices K.3, K.4 and K.5.

1-12 Wharf Street

5.3 On the basis of the VSC method of measurement, out of the seventeen sensitive

receptors, one first floor window (window W2/11) will experience a moderate



adverse impact and the remaining sixteen will experience a negligible impact. It

should however be noted that window W2/11 is in fact a small secondary window

forming part of a larger bay window (see drawing number ROL5877_5_100 annexed

at Appendix K.2). From the plan, it can be seen that room R1/11 is served by a bay

window comprising three separate windows of which window W2/11 is part. The

remaining two windows, including the principal window (W3/11) comfortably satisfy

the BRE Guidelines. As the bay window serves one single room, these three results

should be taken together which then shows that the availability of daylight to this

room will remain very good indeed. In fact, fourteen of the windows do not even

register on the scale of impact as they will all continue to receive in excess of 27%

VSC and therefore fully satisfy the target design standards of the BRE Guidelines in

any event.

5.4 Using the alternative Daylight Distribution method of measurement, there are fifteen

sensitive receptors as Daylight Distribution applies to “rooms” rather than “ windows”

and out of those fifteen sensitive receptors, all fifteen will experience a negligible

impact with ten out of the fifteen experiencing no measurable loss of internal Daylight

Distribution at all.

5.5 The tests show that there will be no material loss of direct daylight from the sky which

will be noticeable in terms of the outlook from the windows and that there also will be

no noticeable or material loss of internal Daylight Distribution.

5.6 The results of the sunlight analysis show that there will be no material loss of winter

or annual sunlight and that these receptors will all comfortably satisfy the BRE target

standards. The impact on sunlight will therefore be negligible.

50-55 Catteshall Lane

5.7 All of the receptors in 50-55 Catteshall Lane comfortably satisfy the VSC and Daylight

Distribution target guidelines. In terms of VSC, all of the residual values will be in

excess of 27% VSC and none of the rooms in question will experience any loss of

internal Daylight Distribution at all. The impact is therefore negligible.

5.8 The BRE sunlight criteria does not apply to these receptors as they do not face within

90 degrees of due south and as the proposed development lies to the north of the

existing gardens, there will be no additional permanent overshadowing of those



gardens as a result of the development and therefore neither sunlight nor

overshadowing needs to be tested.

2-28 Victoria Road

5.9 Out of the thirty six sensitive receptors identified for these properties, all thirty six will

fall within the negligible significance criteria with many of those receptors not only

comfortably satisfying the BRE Guidelines but achieving a target VSC value in excess

of 27%. Likewise, the results of the internal Daylight Distribution analysis show that

all of the rooms will not only fall within the negligible significant criteria for Daylight

Distribution, the vast majority (almost two thirds) will experience no measureable loss

of internal Daylight Distribution at all, and even where there is a numerical loss, the

quantum of loss is so small as to be imperceptible.

5.10 In terms of sunlight, it is only 10-28 Victoria Road that marginally face within 90

degrees of due south and hence fall within the BRE sunlight criteria. Those receptors

generally face west and therefore even if they were totally unobstructed, are only

capable of receiving approximately half of the total available sunlight hours on the

spring equinox in comparison to a window facing due south. As the orientation of

these receptors is such that they are only capable of receiving half of the available

sunlight on the spring equinox, the targets and significance criteria should be applied

accordingly and requires a certain amount of judgement and interpretation. The

numerical results of the sunlight analysis sets the overall impact in the negligible

category.

5.11 Annexed at Appendix K.6 is drawing number ROL5877_5_300 and Table P4 which

illustrates the extent of permanent overshadowing under “existing” and “proposed”

conditions. The green circular hatching indicates the amount of existing permanent

shadow and the extra amount of permanent overshadowing is illustrated by the red

circular hatching.

5.12 The BRE Guidelines permit the extent of overshadowing to be increased by a factor

of 20%.

5.13 From the results of the technical analysis, the extent of additional permanent

overshadowing will be limited to six out of the twelve gardens and the extent of that

permanent overshadowing will not only be well within the BRE Guidelines but will be

so small as to be imperceptible. The impact is therefore negligible.



Daylight, Sunlight and Overshadowing of Completed Development

5.14 The drawings and tables in Appendix K7 illustrate the location of a sample of

habitable rooms at ground, first and second floor levels where the availability of

daylight and sunlight has been tested. These rooms have been selected as they are

located in those parts of the proposed development where daylight and sunlight is

likely to be at its lowest levels, e.g. in the corners of the courtyards or where some

rooms are served by windows that are recessed within private amenity balconies or

have projecting private amenity balconies over them which results in the “canopy

effect”. The room and window location references on the drawings should be cross

referenced with the room and window location references used in the corresponding

daylight and sunlight tables within the same appendices.

5.15 From the results of the ADF analysis, four rooms were found not to achieve the target

design standard. These were rooms R1/900, R2/910, R5/601 and R4/902. The

reason why all four of these rooms fall short of the target design standard is a result

of the “canopy effect” of either recessed or projecting balconies. Rooms R1/900,

R2/910 and R4/902 have windows that are partially recessed whereas room R5/602

has a private amenity balcony above it. All four windows therefore experience the

“canopy effect” of the projections above the windows and it is therefore unrealistic to

expect to achieve the target daylight (and sunlight) standards in such circumstances.

5.16 Likewise, when the results of the Annual Probable Sunlight Hours and winter sunlight

hours tests are reviewed, there is a parallel correlation in that those windows which

are flush with the external wall of the buildings record very good levels of annual and

winter sunlight and the only marginal shortfalls are where the windows are either

recessed or have projecting private amenity balconies above them.

5.17 Taken on the whole, the daylight and sunlight results that have been obtained are

very good and the overall design performs very well. Where there are a very small

number of shortfalls in daylight or sunlight, that shortfall arises due to the external

private amenity space in front of each of the windows and the positive benefit of

providing amenity space should be balanced against the resulting lighting conditions.

With such a small number of very minor transgressions, the overall impact is

considered to be negligible.

5.18 Appendix K8 summarises the results of the permanent overshadowing analysis of the

amenity areas within the proposed development.



5.19 The results of the technical analysis show that the extent of permanent

overshadowing of the proposed amenity areas will be comfortably within the BRE

Guidelines. Although the proposed design meets the target design standards, there

will be some parts of the amenity space that will be in permanent shadow on the

spring equinox and the impact is therefore to be classed as negligible.

Cumulative Impact

5.20 There will be no cumulative impacts on the identified sensitive receptors as a result of

other neighbouring development other than the proposed development itself.

Although other developments in reasonably close proximity of the Site have been

identified, none of those developments will have any impact at all on the availability of

daylight or sunlight nor will they affect the amount of overshadowing of existing

neighbouring amenity space. Taking all of these factors into account, the receptors

that fall within the testing criteria will not be affected by any other development

beyond the Site itself, both now and in the foreseeable future and there therefore are

no reasonably foreseeable cumulative effects that would give rise to any further

impacts than those identified within the present analysis.



6.0 EVALUATION OF SIGNIFICANCE

6.1 The impacts measured for the daylight, sunlight and overshadowing that will be

experienced by the existing neighbouring dwellings will all be within the negligible

significance criteria. In the vast majority of tests undertaken, the results show that

there will be no material impact at all on the neighbouring dwellings in that the

receptors will comfortably satisfy the target design standards even before any

reduction ratio is applied.

6.2 No single neighbouring dwelling or collection of dwellings as a whole, will experience

any material detrimental or adverse impact as a result of the proposed development

either in terms of daylight, sunlight or overshadowing, as the proposed development

comfortably satisfies all of the relevant standards within the BRE Guidelines and

British Standard Code of Practice for Daylighting. For the proposed new dwellings,

there are no baseline conditions and there therefore is no “impact” to be measured.

Instead, the quality of daylight, sunlight and overshadowing needs to be measured on

the absolute scales within the Guidelines. The receptors chosen for the analysis

were a sample of those habitable rooms that are likely to experience the lowest levels

of natural daylight and sunlight. All of the rooms which have conventional flush

windows will comfortably satisfy the target design standards but four rooms in the

sample fell below that target standard as a result of the windows being recessed or

where they were set below a projecting private amenity balcony. The number of

windows which did not meet the target design standard, coupled with the quantum by

which there was a shortfall of ADF and/or APSH will be relatively small and should be

balanced against the benefit of private amenity space provided by the balconies.

That benefit offsets the relatively small shortfall in lighting conditions and in view of

the very small number of receptors that fall within this category, the impact is

considered to be negligible.



7.0 OPPORTUNITIES FOR MITIGATION AND ENHANCEMENT

7.1 Throughout the design process, the scale and “massing” of the proposed buildings

has been influenced by the previous proposals for the Site, townscape issues and

input from Anstey Horne & Company Limited to ensure that the proposed new

buildings would not result in any material or unreasonable impact on existing

neighbouring amenity. The principal mitigating measure in this regard has therefore

been the development of the design itself to ensure that the final product satisfies the

Council’s policy objectives.



8.0 RESIDUAL IMPACTS

8.1 There will be no residual impact as no mitigation measures are required.



9.0 SUMMARY AND CONCLUSIONS

9.1 For the purpose of this Environmental Statement, the recognised standards to be

adopted for assessing the impact of the proposals on existing neighbouring dwellings

are the Building Research Establishment Guidelines “Site Layout Planning for

Daylight and Sunlight – A Guide to Good Practice” 1991, and the British Standard

Code of Practice for Daylighting, BS8206 Part 2, 2008. These standards limit the

sensitive receptors windows and rooms within residential properties around the Site

that have the potential to be affected.

9.2 Following a detailed site appraisal, these sensitive receptors have been identified as

1-12 Wharf Street, 50-55 Catteshall Lane and 2-28 Victoria Road. The results of the

technical analysis demonstrate that the proposed development will practically fully

satisfy the BRE Guidelines in terms of impact on daylight, sunlight and

overshadowing. For the vast majority of the receptors, the impacts that have been

measured will fall within the negligible significance criteria and for the very small

number of receptors which do not fully satisfy the BRE Guideline standards, the

impact will only be minor adverse and also be influenced by valid mitigating factors

such as windows serving non-habitable rooms or secondary windows where other

primary windows remain unaffected.

9.3 The impact on sunlight and overshadowing will also be negligible.

9.4 Although there will be a measurable loss of direct daylight and sunlight which will be

noticeable in terms of the outlook from the receptors, the loss of light will be

negligible and the amount of light that will remain will be more than adequate for

each of the design uses for the rooms served by each of the receptors. The amenity

enjoyed by the neighbouring dwellings will therefore not be affected.

9.5 In overall conclusion, the proposed development will not give rise to any material

deterioration to the amenity enjoyed by the existing neighbouring buildings as

demonstrated by the numerical results and it should therefore follow that the Council’s

policy objectives have been satisfied.



9.6 A summary of the potential impact of the proposed development is set out in the table

below.

Description of Impact

Description of Significance

Description of Residual Impact

Description of Significant of

Residual Impact

Loss of daylight to 1-12 Wharf Street

Negative, direct permanent and negligible.

Daylight levels to habitable rooms will be reduced but will remain above the recognised target design standards.


Loss of sunlight to 1-12 Wharf Road




Loss of daylight to 50-55 Catteshall Lane




Loss of daylight to 2-28 Victoria Road




Loss of sunlight to 2-28 Victoria Road




Overshadowing of rear gardens of 2-28 Victoria Road






REFERENCES

Building Research Establishment (BRE) Guidelines “Site Layout Planning for Daylight and

Sunlight – A Guide to Good Practice” 1991.

British Standard BS8206-2; 2008, Lighting for Buildings – Code of Practice for Daylighting.

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