Daylight and sunlight reports in Wandsworth

Which BRE edition applies

The guide is advisory, not law. Its current edition is the third, revised to reflect the European daylight standard, and Wandsworth names that edition in its checklist. We work to the edition the council specifies, and say so on the first page of the report.

The geometric screens in the guide are only a first step. For a rear extension the widely used rule is a line at 45 degrees from the centre of the nearest neighbouring window, in plan and in elevation. If the new work stays clear of that line, the effect on that window is usually small. If it crosses, the fuller calculations follow, and the report explains any loss in the context of the street.

Wandsworth's homes and why light is contested here

Wandsworth has 137,393 households. Only 31.4 per cent live in a house, and the Victorian terraces of Battersea, Putney and Tooting sit close together with narrow gardens. Domestic gardens still cover 21.5 per cent of the land, so the rear of a terrace is where most disputes over light begin.

Loft conversions raise the question for a different reason. A roof extension changes the shadow cast over the neighbouring garden in the afternoon, and the guide's overshadowing test for gardens looks at exactly that.

The borough has 46 conservation areas and 312 listed building entries, so a good deal of the housing stock cannot be altered freely. In those streets the room for compromise on height is small, and an early light test can settle the design before it is drawn.

How Wandsworth decides, and what that means for your report

The council decided 977 householder applications in the latest returns and granted 91.9 per cent of them. A high grant rate does not mean light is ignored: officers read the amenity policy closely, and a well-argued report is part of a proposal that suits its neighbours.

The planning framework is the Wandsworth Local Plan 2023-2038, with the Housing SPD (covers rear extensions, basements, roof extensions and loft conversions) giving the design rules for extensions, basements and roof additions. We read the Housing SPD for the specific depth and height limits on rear extensions, and test every case against both documents.

Where a basement is involved, our basement impact assessment page covers the separate tests for ground and water.

What our report contains, and how we price it

You receive a written report with the model, the affected windows and rooms, the test results before and after, and a plain-English conclusion. Where a figure falls outside the guide's guidelines, the report says so and argues the case in context. A second chartered technologist, never the one who built the model, checks the geometry and the results before issue.

There is no list price, because the cost depends on the number of neighbouring windows. You receive a fixed quote after a free constraints check, which also tells you whether the council will treat the report as a validation requirement for your scheme.

Read the national rules on our daylight and sunlight report page, see the other services on the Wandsworth area page, or start with planning drawings if you have no design yet.