Daylight and Sunlight Assessments in Kensington and Chelsea

If you are planning a new development or extension in the Royal Borough of Kensington and Chelsea, a daylight and sunlight assessment is often a key requirement for securing planning permission. Whether you are extending a period townhouse in Notting Hill, adding a basement or loft conversion in Chelsea, or proposing a new residential development in Earl's Court or North Kensington, your proposals may affect the daylight and sunlight enjoyed by neighbouring properties and RBKC's planning officers will expect you to demonstrate that any impacts are acceptable.

At Sunlight Assessments, we prepare BRE-compliant daylight and sunlight assessments for planning applications across the Royal Borough of Kensington and Chelsea. Our reports are clear, technically robust, and written to support a smooth planning process.

When does Kensington and Chelsea require a daylight and sunlight assessment?

Not every application in Kensington and Chelsea will require a formal assessment, but there are common scenarios where one is expected:

• Extensions that extend close to a boundary with a neighbouring property, particularly where habitable rooms face the affected elevation
• New residential developments where neighbouring properties may lose access to natural light
• Applications where the Local Planning Authority has identified daylight and sunlight as a material planning consideration
• Basement extensions, loft conversions, and rear additions in the borough's densely built Victorian and Georgian terraces, where the proximity of neighbouring windows can make impacts particularly sensitive
• Conversions and changes of use where new habitable rooms are proposed

If you are unsure whether your scheme requires an assessment, we are happy to advise on this at no cost.

Kensington and Chelsea's local planning policy

RBKC's approach to daylight and sunlight is guided by its Local Plan 2024, adopted on 24 July 2024. The Local Plan sets out the council's vision and policies for development across the borough and is the primary document used to determine planning applications. It places strong emphasis on protecting the amenity of existing residents, including their access to natural light - a particularly important consideration in a borough characterised by dense historic streets with tightly arranged terraces and mansion blocks.

In assessing the impact of development on natural light, RBKC applies the methodology set out in the BRE guidance document BR 209: Site layout planning for daylight and sunlight (2022 edition), the nationally recognised benchmark for daylight and sunlight assessments in the UK. Kensington and Chelsea's historic character means that assessments in this borough often require particular care - development in conservation areas, or adjacent to listed buildings, can involve heightened sensitivity to changes in daylight and sunlight.

RBKC has also adopted a number of Supplementary Planning Documents (SPDs) that are relevant to amenity considerations. The Basements SPD (adopted April 2016) is directly relevant to basement extension applications, where light wells and the removal of below-ground structures can affect the daylight available to neighbouring properties. More broadly, the council's design guidance emphasises that development should protect and where possible enhance the amenity of neighbouring occupiers.

You can find RBKC's Local Plan and planning policy documents at rbkc.gov.uk/planning-and-building-control/planning-policy, the Local Plan 2024 at rbkc.gov.uk/planning-and-building-control/planning-policy/local-plan, and the SPDs at rbkc.gov.uk/planning-and-building-control/planning-policy/supplementary-planning-documents-and-guidance.

How the assessment works

We use the methodology set out in BRE BR 209 to assess the impact of proposed development on daylight and sunlight. The key tests we carry out include:

Vertical Sky Component (VSC): This measures the amount of sky visible from the centre of a window. BRE guidance recommends that a VSC of 27% or more is generally considered adequate. Where a development results in a VSC that is less than 0.8 times its former value, the reduction may be noticeable to occupants.

No-Sky Line (NSL): This assesses the distribution of daylight within a room by plotting the line beyond which no sky is visible. Where the area of a room that can receive direct skylight is reduced by more than 20%, occupants are likely to notice a deterioration in the quality of daylight.

Annual Probable Sunlight Hours (APSH): This test is used to assess access to sunlight for windows that face within 90° of due south. It considers both the winter and annual totals to determine whether sunlight losses are likely to be material.

Where appropriate, we also carry out sun-on-ground studies to assess the impact on garden or amenity spaces.

What our Kensington and Chelsea report includes

Our daylight and sunlight assessments for Kensington and Chelsea planning applications typically include:

• A clear description of the proposed development and the surrounding context
• Identification of all relevant neighbouring windows and amenity spaces
• VSC and NSL calculations for affected neighbouring properties
• APSH calculations where required
• A comparison of results against BRE BR 209 benchmarks
• A professional assessment of whether any identified impacts are likely to be considered material in planning terms
• Recommendations for design amendments where required, to help reduce impacts and support approval

All reports are produced by qualified consultants with experience of working in Kensington and Chelsea and across the wider London area.

Get in touch

If you are planning a development in Kensington and Chelsea and would like to discuss whether you need a daylight and sunlight assessment, please get in touch. We offer a free initial consultation and can usually turn around a report within 5 working days of receiving the necessary information.