Number 37 Dover Street in Mayfair, a white stucco Georgian townhouse with arched ground-floor windows and iron railings — Photograph: stevecadman (CC BY-SA 2.0)

01Specialist reports

Daylight and sunlight reports for London schemes

When a neighbour's window, a council's local list or a London Plan policy asks whether your building takes too much light, the answer has to be measured. We model the surroundings, run the tests the guidance names and write the result for an officer. From £985, fixed before we start.

From £985

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Our fee for daylight and sunlight report: from £985, no VAT to add. Covered in full, with its own guide and fee, at propertyarchitecture.co.uk.

02The fee

One fixed fee, published

Daylight and sunlight report

from £985

The total you pay. No VAT to add.

Ask for your fixed fee

What you get

A three-dimensional model of your building and the neighbours that face it
The tests the BRE guidance sets, run on each affected window and room
A plain-English reading of the numbers for the officer and for you
A report in the form a London council expects, with the policy tests it will apply
Redesign advice if a small change would remove the harm

The report is a stand-alone fee. A council only requires one if it is on its published local list of requirements, so we confirm that first; our fee carries no VAT to add.

03How it runs

From the neighbour's window to a measured answer

The sums come before the drawings are final, so the design can still change.

Rear view of brick terraced houses in London with slate roofs and chimney stacks along the shared roofline — Photograph: Ben Hadfield

04Specialist reports

When a council asks for one

A report is a validation requirement only when it is on the council's local list, and the list must have been published less than two years before the application. That makes it a question of your council, not a universal rule: a rear extension in one borough needs none, while a mansard or a new block in another is returned without it.

National policy asks that development keep acceptable living standards for neighbours, including access to daylight and sunlight, and rules out an unacceptable loss of either for neighbouring residents. London policy D6 adds that new and surrounding housing should receive sufficient light for its context, while avoiding overheating.

Cornwall Terrace on the Outer Circle by Regent's Park, a long cream stucco Regency terrace with columned porticoes — A long Regency terrace: new bulk at the rear is tested against every window along the row.Photograph: ell brown, CC BY 2.0

05Specialist reports

What the guidance measures, and its limits

The reference is the BRE guide, Site layout planning for daylight and sunlight, in its third edition of June 2022. Its figures are advisory, not law. Councils also use simpler rules of thumb for extensions: Merton's design guidance, for example, asks that a multi-storey rear projection not break a 45-degree line drawn from the centre of the neighbour's nearest ground-floor habitable room.

London's guidance says BRE targets should be applied with flexibility in dense areas, and compares impacts with broadly similar homes nearby. It gives no numeric targets of its own. A good report therefore reads the numbers in context, and does not simply declare a pass or a fail.

Each result is tied to the policy an officer will apply.

06Specialist reports

Cheaper to ease the design than to argue

A report that finds a breach does not end a scheme. Lowering a flank by 300 mm, stepping the upper floor back, or changing a roof from a flat to a pitch can bring a neighbour's window back inside the guidance. These are cheap changes at drawing stage and costly ones after consent.

We run the model alongside our planning drawings and rear extension drawings, so a daylight finding can change the design before it is submitted rather than after the council has asked.

Georgian brick terrace on Bedford Square in Bloomsbury, with arched doorways, sash windows and black iron railings — A Georgian terrace in Bloomsbury: floor-to-ceiling sashes whose light an extension must not take away.Photograph: Steve Cadman from London, U.K., CC BY-SA 2.0

07The record

Figures that shape the job

3rd ed.
Edition of the BRE guide to daylight and sunlight, published June 2022 and revised to reflect BS EN 17037.
Source: RICS Built Environment Journal, BRE daylight and sunlight guidance, checked 17 Oct 2026
45°
Rule of thumb for multi-storey rear projections, measured from the centre of the neighbour's nearest ground-floor habitable room.
Source: Merton Council, Small Sites Toolkit 01 Design Guidance, paragraph 6.1.11, checked 17 Oct 2026
D6
London Plan policy requiring sufficient daylight and sunlight for new and surrounding housing, appropriate to context.
Source: London Plan 2021, policy D6 part D, checked 15 Oct 2026
Flexibility
The Mayor's Housing SPG asks for an appropriate degree of flexibility in applying BRE guidelines, especially at higher density.
Source: Mayor of London, Housing SPG 2016, paragraph 1.3.45, checked 17 Oct 2026
Two stages
London guidance assesses daylight first by the BRE tests, then by the location and wider context.
Source: GLA, Housing Design Standards London Plan Guidance, June 2023, checked 17 Oct 2026
Local list
A report is a validation requirement only if it is on the council's local list, published less than two years before.
Source: Planning Practice Guidance, Making an application, checked 15 Oct 2026
NPPF
National policy resists development that gives neighbours an unacceptable level of access to daylight and sunlight.
Source: National Planning Policy Framework, August 2026, checked 15 Oct 2026

08Questions

What clients ask before they instruct us

Do I need a daylight report for a house extension?

Usually not, unless your council's local list asks for one or a neighbour's window is close and affected. We check the list for your borough before we quote.

Is the BRE guidance a legal limit?

No. It is advice, and councils apply it with judgement. London policy in particular asks for flexibility where homes are dense, so a result near a target is read in its setting.

What does the report cost?

From £985, fixed before we start, with no VAT to add. If your scheme is large or has many neighbouring windows, the quote says so in writing before you commit.

Can you review a report written by someone else?

Yes. If a neighbour's consultant has objected on light grounds, we can read their method and tell you where it follows the guidance and where it does not.

Does it include a party wall notice?

No. A light assessment is a planning matter; party wall is under a different Act. We prepare party wall notices as a separate fixed-price service.

09Related

Kensington street lined with brick townhouses and lit streetlamps beneath an orange dusk sky

Send us the address of your house.

We look up the conservation area, listing and Article 4 position, then reply with a fixed fee. A message before 3pm is answered the same working day.

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