F I F E
C O U N C I L
Planning Committee
17th March 2009
Agenda Item No. 9
PLANNING CUSTOMER GUIDELINES ON DAYLIGHT AND SUNLIGHT
1.0
INTRODUCTION
1.1
The purpose of this report is to seek approval for the new Planning Customer Guidelines on
Daylight and Sunlight. The guidance seeks to set out relevant criteria and advice on how to
measure the impacts on existing buildings and adjoining land in order to achieve a high quality
in all new developments without undue loss of daylight and sunlight. It is intended that this
guideline will apply on a Fife wide basis and compliment relevant policies of all Local Plans to
further protect and safeguard residential amenity.
2.0
FINANCIAL IMPLICATIONS
2.1
There are no financial implications arising from this report.
3.0
LEGAL AND RISK IMPLICATIONS
3.1
These guidelines are drawn from advice in BRE Report Site Layout Planning (1991). There is
currently no guidance offered by the Scottish Government. This advice will be material to the
consideration of a planning application when it is considered a proposal may have an impact
on property and land in terms of unacceptable levels of overshadowing or loss of sunlight.
4.0
CONSULTATIONS
Development Services has drafted this guideline based on comments received from
Development Services planners processing applications for planning permission and
customers. A series of training workshops will be held for Development Service Planners to
explain the background to the new guideline and how to implement this in relation to different
proposals.
5.0
CONTEXT FOR NEW GUIDANCE
5.1
Development Services have not up until now had formal specific daylight/sunlight guidance but
have used the above BRE guidance in assessments. Whilst there are policies in all Local
Plans that seek to protect residential amenity they do not refer specifically to daylight/sunlight
issues. It has become clear from discussions with Development Service planners and
customers that this guidance is required to clarify what is acceptable and what is not when
assessing a proposal in relation to daylight and sunlight issues.
5.2
The new revised guidelines will be part of the suite of other Development Services customer
guidelines. This version will be for customers whilst a longer more technical version will be
available for Development Service planners to use based on a number of in-house training
workshops.
6.0
NEW GUIDANCE
6.1
The new guidelines will outline what is acceptable and what is not acceptable in terms of
daylight and sunlight considerations. Applications that are deemed to have the potential to
have an adverse impact upon the current levels of sunlight/daylight enjoyed by adjoining
properties and buildings will need to be accompanied by the methods of daylighting and
sunlighting assessment set out in the BRE Report Site Layout Planning and where appropriate
demonstrate both ‘before’ and ‘after’ circumstances. The guidelines address the following:
The main differences between daylight and sunlight
The guidance explains the main differences between daylight and sunlight by highlighting a
number of important facts that need to be taken into account when considering
daylight/sunlight issues in relation to development proposal.
When to consider daylighting/sunlighting issues
The guidelines set out a number of factors that need to be taken into account when
considering a proposal in relation to daylighting/sunlighting issues.
Methods to ensure that adequate daylight is achieved and undue overshadowing does
not occur
The guidance seeks to highlight and clearly explain the main differences between three
methods of calculating daylight and sunlight in relation to a new development. The guidance
advocates that the design of residential environments must seek to ensure that adequate
levels of natural light can be achieved within new dwellings and unacceptable impacts on light
to nearby properties are minimised or preferably avoided.
7.0
CONCLUSIONS
7.1
The purpose of this new planning customer guideline is to help both Council staff and
customers make decisions when assessing a planning application or putting together a
proposed development. The guideline is intended to help support current local plan policy on
residential amenity and provide specific guidance so that quality development is achieved
without compromise.
8.0
RECOMMENDATIONS
8.1
It is recommended that Members:


Adopt the new planning customer guidelines detailed above on daylight and sunlight.
Note that a published version will be made available to customers in the standard format
for Planning Customer Guidelines.
Keith Winter
Head of Development Services
Jim Birrell
Development Manager
(Development and Regeneration)
Fife House
North Street
Glenrothes
Author: Mark R Russell and Sarah Johnston 08451 555 555 ext. 473835
Date: February 2008
BACKGROUND PAPERS
Under Section 50(d) of the Local Government (Scotland) Act 1973 the following background papers
were relied upon in the preparation of this report:


BRE Report Site Layout Planning
New Planning guidelines on daylight/sunlight
Appendix 1
Daylight and Sunlight Guidance
Introduction
This guidance sets out the relevant criteria and advice how to measure the impacts on
existing buildings and adjoining land in order to achieve a high quality in all new
developments. This has been based on Building Research Establishment Report Site Layout
for Daylight and Sunlight: A Guide to Good Practice by P J Littlefair (1991). Each application
will be assessed on its merits.
What does this guidance cover?
This guideline is applied on a Fife wide basis and relates to all new development including
extensions to existing buildings and changes of use. This guidance seeks to complement
relevant policies of all Local Plans to further protect and safeguard residential amenity.
Applications that are deemed to have the potential to have an adverse impact upon the
current levels of sunlight/daylight enjoyed by adjoining properties and buildings will need to be
accompanied by the methods of daylighting and sunlighting assessment set out in the BRE
Report Site Layout Planning and where appropriate demonstrate both ‘before’ and ‘after’
circumstances.
Sunlight/daylight-What are the main differences?
Daylight is defined as being the volume of natural light that enters a building to provide
satisfactory illumination of internal accommodation between sun rise and sunset. This can be
known as ambient light. Sunlight refers to direct sunshine. Below are some helpful hints to
take into account:

The sun rises in the east and sets in the west.

The sun reaches its maximum height around noon and will generally be due
south at this time.

The sun is higher in the sky in summer months as opposed to winter months.

The sun elevation in mid-winter does not generally rise above 10 degrees in
Scotland and therefore can cast long shadows.
When do I need to consider daylight/overshadowing issues?
Before submitting your planning application (check first that planning permission is required in
the first instance) you should contact Development Services to check whether a
daylighting/overshadowing assessment is required. The Council will require as a minimum
that:
All new development including extensions
overshadowing of neighbouring properties.
will
be
designed
to
minimise
The greater part of any overshadowing that occurs will be confined to applicants own
land.
There are a number of major factors that have to be taken into account in any assessment.
These are as follows:

Height;

Distance to boundaries;

Size of Plot;

Orientation; and

Topography
The Council will not support extensions or any new development that would result in the loss
of sunlight leading to overshadowing for the majority of the day.
Whilst a building warrant will ensure that there is a minimum level of daylighting, all buildings
including changes of use and extensions/new developments will still be required to provide
adequate levels of sunlight. A building warrant is no guarantee that planning permission will
be granted.
The 45 Degree rule of thumb
At all times care should be taken in the design of residential environments to ensure that
adequate levels of natural light (based on Building Standards) can be achieved within new
dwellings and unacceptable impacts on light to nearby properties are minimised and
preferably avoided. Proposed dwellings should be laid out so as to maximise the penetration
of sunlight to main rooms and gardens. The overshadowing of amenity spaces, particularly
those that are used for outdoor seating should be minimised.
The Building Research Establishment (BRE) guidelines “Site Layout Planning for Daylight and
Sunlight: A Guide to Good Practice” (1991) provides guidance on avoiding unacceptable
impacts and sets out non-mandatory targets for levels of daylight and sunlight within existing
and proposed development. The Council will generally apply the BRE guidance targets where
new development affects natural light to existing properties.
A useful guideline to measuring the impact of the new development is the 45 degree rule of
thumb method as can be seen in Diagram 1 below.
Diagram 1
New flatted housing layouts in the form of ‘T’ shaped plans (i.e. projection to rear elevation),
courts or quadrangles, projecting wing arrangements (on side or end elevations), house
designs with projections and angled frontages, and house extensions which adjoin the front or
rear of a house are required to satisfy the 45 degree assessment method.
Application of the 45° approach to domestic extensions is summarised in Diagram 1 above.
A significant amount of light is likely to be blocked if the centre of the window (or for a floorto- ceiling window, as here, a point two metres form the ground) lies within the 45° lines of
both plan and elevation. The method applies only where the nearest side of the extension is
at a right angle to the window and not for windows which directly face it.
The 45 degree method can also be applied to new house designs in situations where
windows are placed at the corners of internal courtyards; ‘L’ or ‘T’ shaped or angled blocks.
In all new residential development proposals where future extension(s) could cause serious
loss of light to neighbouring property the Council will consider removing permitted
development rights.
25 Degree Rule of Thumb
This approach should be used when the new development directly faces the affected window.
Suitable daylight for habitable rooms is achieved when a 25 degree vertical angle taken from
the centre of the lowest windows is kept unobstructed. See diagram 2. The recommended
distance between the buildings is dependent on the opposing property ridge height. If the
building opposite has a high ridge, the loss of daylight will be more notable than if the building
has a lower ridge height. If the proposed development fails this test and that of the 45 degree
method then further investigation and evidence will be required by the Council in order to
assess whether an unacceptable loss of sunlight/daylight will occur.
Diagram 2
The Vertical Sky Component Method
In cases where it is not possible to meet the criteria set out above and where a more detailed
assessment is necessary, for example in areas of historic townscape, this should be made by
calculating the vertical sky component. The methodology for calculating the vertical sky
component is set out in more detail in the BRE report “Site Layout Planning” which also
contains advice and guidance on interior daylighting standards. (This information should be
submitted with the application).
A satisfactory level of daylight is assessed by calculating the vertical sky component for
neighbouring property whether existing or, when none exists, for possible development equal
to the proposed.
New development adjacent to vacant land should as a minimum requirement ensure that this
land retains the potential for good diffuse daylighting.
Sunlight
All new development should seek in line with other policies and guidance to maximise the
benefits of sunlight to provide a pleasant living environment and promote solar gain.
How to contact us
Development Services
Forth House
Abbotshall Road
Kirkcaldy
KY1 1RU
Tel: 01592 583350
Email: development.central@fife.gov.uk
Development Services
County Buildings
St Catherine Street
Cupar
KY15 4TB
Tel: 01334 659334
Email: development.east@fife.gov.uk
Development Services
New City House
1 Edgar Street
Dunfermline
KY12 7EP
Tel: 01383 609120
Email: development.west@fife.gov.uk