Understanding the daylight requirements in West Lothian matters for anyone proposing a house extension, an infill plot or a larger residential scheme in Livingston, Bathgate, Linlithgow or the smaller towns and villages across the county. West Lothian Council is the local planning authority for the whole area, and daylight, sunlight and privacy are treated as central parts of residential amenity. This guide explains which adopted policies apply, the local separation standards that come into play, and what a daylight and sunlight assessment to recognised standards involves.
Daylight requirements in West Lothian: the policy framework
The statutory development plan for the area is made up of the National Planning Framework 4 (NPF4), adopted by Scottish Ministers on 13 February 2023, and the West Lothian Local Development Plan (LDP), adopted by the Council on 4 September 2018. Both are read together, and applications are determined in accordance with the development plan unless material considerations indicate otherwise. A successor plan (LDP 2) is being prepared, but until it is adopted the 2018 LDP remains the local part of the plan.
At the national level, two NPF4 policies are most relevant to daylight and amenity:
- Policy 14 (Design, quality and place), which takes a design-led approach and tests proposals against the six qualities of successful places; and
- Policy 16 (Quality homes), which seeks well-designed, sustainable homes with good internal and external living conditions for future occupiers.
The local design and amenity policies
At the local level, the lead policy is Policy DES 1 (Design Principles) of the West Lothian LDP. Among its requirements, it expects new development to have no significant adverse impact on the amenity of adjacent properties - the test under which loss of daylight, sunlight, privacy and outlook to neighbours is judged. Residential proposals are also assessed against the LDP's housing policies, including Policy HOU 1 and Policy HOU 3, which deal with housing development and the quality of new homes.
The Residential Development Guide and its separation distances
What sets West Lothian apart from many authorities is the detail of its adopted local guidance. The Supplementary Guidance: Residential Development Guide (adopted in 2019) directly supports policies DES 1, HOU 1 and HOU 3, and sets out specific amenity and privacy standards, including:
- Minimum separation distances between single and two-storey dwellings - a window-to-window distance of 18 metres for front-to-front and rear-to-rear relationships, with reduced distances for side and gable relationships;
- A minimum of 1 metre of space either side of a mutual boundary, with at least 4 metres between buildings where only a minor (hall, stair or landing) window is involved;
- A requirement that, where a building is greater than two storeys, these separation distances may need to be increased to ensure daylighting standards are met; and
- Garden-ground standards (with a minimum rear-garden depth used to allow drying and amenity space), which are relevant to overshadowing of private gardens.
Critically for our purposes, the Residential Development Guide states that where there is any suggestion that new housing could cause an excessive loss of light or overshadowing of neighbouring properties, applicants may be required to support their proposals with technical assessment - and it expressly points to the BRE methodology described below.
How BRE BR 209 fits in
The Residential Development Guide names the Building Research Establishment report Site Layout Planning for Daylight and Sunlight: A Guide to Good Practice as the assessment method for daylight and sunlight, requiring both before and after circumstances to be demonstrated. The current edition of that guidance is BRE BR 209: Site Layout Planning for Daylight and Sunlight - A Guide to Good Practice (2022 edition), read alongside the British Standard BS EN 17037. In short, BR 209 supplies the measurable tests that allow a planning officer to judge whether a scheme meets the amenity aims of Policy DES 1 and the standards in the Residential Development Guide, as well as NPF4 Policies 14 and 16. (West Lothian lies wholly outside Scotland's National Parks, so the Council is the planning authority across the whole area.)
What a daylight and sunlight assessment involves
A BRE-based assessment usually answers two questions: how much daylight and sunlight neighbouring properties will keep, and how much future occupiers of the proposed development will receive. The principal tests include:
- Vertical Sky Component (VSC) - the amount of skylight reaching the centre of a neighbour's window, with a guideline value of 27%, or no worse than 0.8 times its previous value;
- Daylight distribution (the no-sky line) - how well daylight reaches across the depth of a room;
- Annual Probable Sunlight Hours (APSH) - the sunlight reaching windows with a significant southerly aspect, tested across the whole year and the winter months; and
- Overshadowing of gardens and amenity space - using the sun-on-ground test on the equinox, relevant given the Guide's garden-ground standards.
A clear, BRE-compliant report helps a West Lothian planning officer weigh a proposal against Policy DES 1 and the separation and amenity standards in the Residential Development Guide. It is particularly useful for two-storey rear or side extensions in the older streets of Linlithgow and Bathgate, for higher-density infill in Livingston, and for any scheme where a proposal sits closer than the guide's separation distances and the impact on a neighbour's daylight needs to be tested objectively. A robust assessment cannot promise consent, but it gives officers the evidence to reach a sound decision and helps applicants design out problems before submission.
How Fortress Associates can help
Fortress Associates prepares our daylight and sunlight report service to BRE BR 209 (2022) and BS EN 17037 for projects across Livingston, Bathgate, Linlithgow and the wider West Lothian area. We work nationwide with a typical 4 to 5 working day turnaround and ask for no advance payment. You can see the full range on our services page or contact us to discuss your site. Where a planning submission also needs technical drawings, we produce building warrant and Building (Scotland) Regulations drawings alongside the report. If your project is elsewhere in central Scotland, see our related guide to the daylight requirements in Stirling.
Sources & further reading
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