Daylight and Sunlight ReportsFrom £895
How much does a daylight and sunlight report cost in London?
A daylight and sunlight report for a London extension costs our fixed £895, with no VAT charged. It is prepared by a specialist we coordinate, from a 3D model built on our drawings, and it tests the effect of your scheme on neighbouring windows and gardens against the published BRE guide.
The short answer: one fixed fee, from drawings to report
A daylight and sunlight report costs £895. We build a 3D model of your scheme and the surrounding buildings from the drawings, a specialist we coordinate runs the tests on the neighbours' windows and gardens, and the result comes back as a written report with plain-English conclusions to submit with your planning application.
That report is a specialist's work, delivered through us, not something we do in house, and the model is only as good as the survey beneath it. Where a window fails a test, the report says by how much and what change to the design might reduce the loss, which is the part a planning officer or a neighbour's adviser reads first.
- Model the scheme
A 3D model of your scheme and the neighbouring buildings is built from the survey and drawings.
- Test the windows
Neighbouring windows are tested for the skylight they receive before and after the scheme.
- Test sunlight and gardens
Sunlight to windows and to neighbouring gardens is measured against the guide's targets.
- Write up the result
The report sets out the results and what, if anything, could reduce a loss.
What the tests actually say
The standard reference is the BRE guide Site layout planning for daylight and sunlight, third edition 2022. Its main skylight test says that if the vertical sky component at a window is greater than 27%, enough skylight should still reach it; if it is both less than 27% and less than 0.80 times its former value, the occupants will notice the reduction (BRE BR 209, para 2.2.7).
There is a sunlight test too: a room that can receive more than one quarter of annual probable sunlight hours, including at least 5% in the winter months, should still receive enough (para 3.2.6). For gardens, at least half of a garden or amenity area should receive at least two hours of sunlight on 21 March (para 3.3.17), and the test is also run on the change, at 0.80 of the former value.
The guide is advice, not law
The BRE guide says of itself that its advice is not mandatory and should not be seen as an instrument of planning policy, and that the numbers should be interpreted flexibly. In a tight London street a window may fall below 27% before any development, so the report compares before and after.
In practice councils and neighbours' advisers use the numbers as the common language. A scheme that passes is easy to defend, and one that fails by a small margin is a matter of judgement that the report helps the officer make. We say honestly which one your scheme is likely to be.
Planning and right to light are different
A planning officer weighs the effect on neighbours as one of many factors. A neighbour's right to light is a separate legal right that can arise by long use: where light has been enjoyed for the full period of twenty years without interruption, the right becomes absolute under the Prescription Act 1832.
A daylight report does not settle that. It can show a loss is small, and it helps in a conversation with a neighbour, but a right to light dispute is dealt with outside the planning system, by a surveyor or a solicitor. We are not those advisers, and we say so rather than imply the report clears it.
When you do not need one
Not every extension needs a report. A modest alteration that does not change the neighbours' outlook may never prompt the council to ask for one. A report is for schemes where a neighbour has objected, the council's validation list asks for one, or the building is tall and close.
If your extension is the ordinary kind, our post on rear extension drawings explains the route, and our double storey post covers the case where the light question is likelier to arise. The service is on the daylight and sunlight report page.
Sources
Every figure in this article, where it comes from and a link to the original.
- third edition 2022: BRE, Site layout planning for daylight and sunlight (BR 209), title page (source wording: "Third edition 2022"). www.bcpcouncil.gov.uk
- 27%: BRE BR 209 (2022) para 2.2.7: (source wording: "If this VSC is greater than 27% then enough skylight should still be reaching the window of the existing building"). www.bcpcouncil.gov.uk
- 0.80 times its former value: BRE BR 209 (2022) para 2.2.7: (source wording: "both less than 27% and less than 0.80 times its former value, occupants of the existing building will notice the reduction"). www.bcpcouncil.gov.uk
- more than one quarter of annual probable sunlight hours: BRE BR 209 (2022) para 3.2.6: (source wording: "more than one quarter of annual probable sunlight hours (APSH), including at least 5% of APSH in the winter months between 21 September and 21 March"). www.bcpcouncil.gov.uk
- at least two hours of sunlight on 21 March: BRE BR 209 (2022) para 3.3.17: (source wording: "at least half of a garden or amenity area should receive at least two hours of sunlight on 21 March"). www.bcpcouncil.gov.uk
- the full period of twenty years without interruption: Prescription Act 1832 s3: light "actually enjoyed therewith for the full period of twenty years without interruption" (source wording: "the full period of twenty years without interruption"). www.legislation.gov.uk
Questions people ask
Is the report prepared by you?
Do I pay VAT on your fee?
Does passing the tests guarantee permission?
Does the report deal with right to light?
What if a window fails?
Photographs: Brett Wharton (Unsplash License); William Dmytrow (Unsplash License).
Daylight and Sunlight Reports: a fixed fee from £895
Read more on the daylight and sunlight reports service page, or send your address below and we reply within one working day.
Daylight and Sunlight Reports
from £895
Every price is the full fixed fee you pay. No VAT is charged. Council application fees are paid to the council separately.
What you get
- A 3D model of your scheme and the surrounding buildings built from the drawings
- Skylight tests on neighbouring windows
- Sunlight tests to windows and an overshadowing check on gardens
- A written report setting out the results against the BRE criteria
- The report as a PDF to submit with your planning application