Daylight and Sunlight Assessments in Lambeth

Lambeth's housing is dominated by three and four storey terraces, and the work we do here reflects that: lower ground floor side infills in Vauxhall, Stockwell and Oval, raised rear extensions with terraces in Brixton and Clapham, mansards in Streatham and West Norwood, and the occasional roof extension on a Herne Hill or Tulse Hill villa. Because the houses are tall and the rear returns sit close together, an extension at lower ground or first floor level can reduce the daylight to a neighbour's rear window even when it looks modest on the drawings.

Lambeth's officers are precise about what they want. Where a scheme could affect a neighbour's light, the council expects a BRE 209 assessment of the affected windows and gardens, and if that evidence is missing it will say so in the decision. A good share of our Lambeth instructions come from architects who have had a scheme refused for lack of daylight information and need a report, and design advice, for the resubmission. Reports usually take 4–5 working days; design options can be turned round in a day or two.

Recent daylight and sunlight assessments in Lambeth

Richborne Terrace, SW8 – rear extensions and roof terrace

A lower ground side infill, a first floor rear extension and a roof terrace to a terraced house in Vauxhall. Lambeth had refused it, partly for lack of information on light to the neighbouring house, and a resubmission needed a BRE assessment. Every neighbouring window and garden met the guidelines except one rear window of unconfirmed use, which, treated as habitable, fell short at 0.77 against 0.80. We tested a sloping extension roof and a lower parapet, and with the amended design that window met the guideline too.

The report has been issued and supports the resubmission now being prepared; the outcome will be a matter for the council.

What Lambeth planning officers look for

Lambeth determines applications against the Lambeth Local Plan 2021, adopted in September 2021 and covering the period to 2035, read with the London Plan. The plan's amenity policy requires development to avoid unacceptable loss of daylight and sunlight to neighbouring homes, and the council assesses that loss using BRE BR 209, Site layout planning for daylight and sunlight (2022 edition). Lambeth will also expect new homes to show adequate internal daylight where the layout or orientation gives cause for doubt.

The council's Design Guide SPD (adopted August 2023) sets out in five parts how it expects schemes to be designed. Part 4, Building Alterations, Extensions and Retrofit, is the one that applies to lower ground infills, rear extensions, roof terraces and mansards, and it is explicit that the effect of an extension on a neighbour's light and outlook will be assessed. Part 2, Advice for All Developments, carries the general principles. Where a decision notice cites a lack of daylight information, it is these documents the resubmission has to answer. The Local Plan is at lambeth.gov.uk/planning-building-control/planning-policy-guidance/lambeth-local-plan-2021 and the Design Guide SPD at lambeth.gov.uk/planning-building-control/planning-policy-guidance/supplementary-planning-documents-other-policy-guidance/supplementary-planning-documents-spds.

When you need an assessment in Lambeth

• A lower ground floor side infill or rear extension on the terraces of Vauxhall, Stockwell, Oval and Kennington, where the neighbour's lower ground rear window faces the new roof.
• A first floor rear extension or roof terrace in Brixton, Clapham or Herne Hill, where a new wall or parapet rises in front of the neighbour's half-landing or bedroom window.
• A mansard or full-width dormer in Streatham, West Norwood or Tulse Hill, where the neighbour's rear windows and the garden opposite may lose sky.
• A resubmission after a Lambeth refusal that cited insufficient information on daylight and sunlight, where the report has to address the reason for refusal directly.
• Flats above shops and small infill blocks on Brixton Road, Streatham High Road and Clapham High Street, where internal daylight to the new homes is also assessed.
• Any application where a neighbour has raised concerns about loss of light and the officer has asked for evidence.

How we work

We build a 3D model of the site and its neighbours from the drawings, survey data and photographs, run the BRE tests and send a report with results, marked-up plans and a plain conclusion. The fee is fixed and agreed up front and the report usually takes 4–5 working days. If a window falls short we tell you how far, model the design change that would remove the shortfall, and re-test the revised drawings within the same job. The four tests are:

• Vertical Sky Component (VSC) – the sky a neighbouring window can see, before and after.
• No-Sky Line / daylight distribution (NSL) – how far daylight reaches into the neighbour's room.
• Annual Probable Sunlight Hours (APSH) – direct sun to windows within 90 degrees of south, annually and in winter.
• Sun on ground – the share of a garden that gets two hours of sun on 21 March.

The tests are explained on our VSC, NSL and APSH page and in our guide to the BRE guidelines; the service as a whole is on our daylight and sunlight assessment page.

Frequently asked questions in Lambeth

Lambeth refused my application for lack of daylight information. What does the resubmission need?

A BRE 209 assessment of every neighbouring window and garden that faces the extension, with the method, the before-and-after figures and a clear conclusion. If one window is tight, as at Richborne Terrace, it is better to adjust the design and show the amended result than to submit a marginal number.

Do you assess the neighbour's room as habitable if you cannot see inside?

Yes, unless there is evidence otherwise. Treating an uncertain room as habitable is the conservative approach and the one a Lambeth officer will expect; it means the result holds whatever the room turns out to be.

Can you advise on design changes as part of the report?

Yes, and in Lambeth we usually do. Sloping a roof away from the neighbour, lowering a parapet or shortening a return by a few hundred millimetres is often all it takes, and we model the options and give the architect the dimensions.

Next door, our Southwark page covers the terraces of Camberwell and Peckham.

Get a fixed-fee quote

Send the drawings, the address and, if you have one, the decision notice through our contact page, or use the price calculator for an instant figure. Nick is on 01962 809155 and nick@sunlightassessments.co.uk.