What Types of Developments Commonly Require Daylight Studies?
Daylight studies are commonly required for developments where a proposed building could affect access to natural light for...
We assess how a proposed development may affect daylight and sunlight received by neighbouring windows, rooms, gardens and amenity spaces.
Assessments are prepared using the relevant methods and recommendations within the current BRE guidance. Depending on the project, the analysis may include:
Vertical Sky Component
No-Sky Line or daylight-distribution testing
Annual Probable Sunlight Hours
Sunlight exposure to gardens and amenity spaces
Internal daylight calculations for proposed rooms
Three-dimensional modelling of surrounding buildings and obstructions
The report explains the assessment method, results and any design changes or mitigation that may help improve performance.
A daylight and sunlight impact assessment examines how a proposed development could change the natural light available to neighbouring properties and outdoor spaces. Our assessments can consider:
Daylight received by neighbouring windows
Sunlight received by relevant rooms
Overshadowing of gardens and communal amenity areas
The effect of building height, massing and separation distances
Comparison with an existing building or consented development
Cumulative effects where other schemes are relevant
Where results identify a potential concern, we can test revised building heights, layouts, setbacks or massing options and provide practical advice to the design team.
Internal daylight assessments evaluate whether rooms within a proposed development are likely to receive an appropriate level and distribution of natural light. We assess proposed homes, including apartments, basement accommodation and rooms affected by neighbouring buildings or constrained site layouts. Depending on the project, the study may consider:
Daylight provision within habitable rooms
The distribution of light across the room
Sunlight exposure
Room depth and layout
Window size and position
External obstructions, balconies and overhangs
Where improvements are needed, we can test changes to windows, room layouts, building form or internal arrangements. Internal daylight analysis can also be coordinated with neighbouring-impact assessments and relevant permitted-development submissions.
A daylight and sunlight assessment may be required where a proposed building, extension or change of use could affect neighbouring windows, gardens or amenity spaces, or where the planning authority needs evidence about light within the proposed accommodation.
Send us the site address, proposed plans and any comments from the planning authority. We will review the information and advise on the likely scope, timescale and fee.
A daylight and sunlight assessment provides objective evidence about the natural-light effects of a proposed development.
An impact assessment normally examines whether neighbouring windows, rooms, gardens or amenity spaces could experience a material reduction in daylight or sunlight. An internal assessment considers the natural light available within rooms in the proposed development.
Depending on the planning requirements, the work may include:
The final report sets out the methodology, assumptions, results and conclusions in a format suitable for submission to the planning authority.
First we build a computer model of the current site layout, marking the locations of all the surrounding windows. We then model the proposed building to see what the change is light will be on the surrounding houses. We typically assess windows and gardens, but model rooms when plans are available. The VSC is then assessed (the amount of daylight falling on the window). Then the APSH is calculated – the amount of direct sunlight falling on a window across the whole year.
Many Prior Approval applications, including for Class MA Permitted Developments (office to residential), must be accompanied by an internal daylight assessment. Upward extensions under Class A, AA, AB, AC and AD also all need both an impact assessment, plus an internal assessment.
Absolutely not! We offer a report review service for Local Planning Authorities where we can independently review Daylight Sunlight Assessment reports. Also, we can help homeowners and local pressure groups to write objections to planning applications.
Any development that has the potential to affect the amount of light reaching its neighbours might need a daylight assessment. It is likely that any development in an urban area that is bigger than what it replaces is likely to need an assessment. Most planning applications in London and other big cities need Daylight Sunlight Assessments. When there is a concern that the accommodation may not be well-lit, we can conduct internal daylight assessments. This includes anywhere where there are tall buildings or where buildings are particularly close to each other. In historic buildings, where windows may be small, internal daylight assessments may be necessary.
National planning policy has not adopted the BRE recommendations. It is just a guide. One should adopt the document flexibly – it is not a “pass/fail” test.. There are several situations where deviation from the guide is perfectly acceptable and we can help work out whether that is the case at your development. If impacts can’t be justified, we can always make suggestion on how best to improve you development.
Yes; assessing the overshadowing of gardens and other amenity spaces is an important part of the Daylight and Sunlight Assessment.
A daylight and sunlight assessment examines how a proposed development may affect natural light to neighbouring buildings, windows, rooms, gardens and amenity spaces. It can also assess whether rooms within the proposed development are likely to receive suitable levels of daylight and sunlight.
An assessment may be requested where a new building, extension or change of use could affect neighbouring windows, gardens or amenity areas. It may also be required where the planning authority needs evidence that proposed homes will receive adequate natural light.
Assessments are commonly prepared for residential developments, apartment buildings, house extensions, mixed-use schemes and projects close to neighbouring properties. They may also be appropriate for commercial developments where surrounding homes or sensitive spaces could be affected.
Useful information includes the site address, existing and proposed drawings, site plans, elevations, floor plans and details of nearby buildings. Where available, measured survey information and comments from the planning authority should also be provided.
The assessment considers the position and use of neighbouring windows, rooms, gardens and amenity spaces in relation to the proposed development. A three-dimensional model may be used to compare existing and proposed daylight and sunlight conditions.
Yes. Internal daylight assessments can evaluate whether rooms within a proposed development are likely to receive an appropriate level and distribution of natural light. Factors such as window size, room depth, layout, orientation, balconies and external obstructions may be considered.
Yes. Sunlight availability can be assessed for neighbouring gardens, courtyards and communal amenity spaces where these areas may be affected by a proposed development.
Yes. Overshadowing can be assessed where a proposal may affect gardens, amenity spaces or neighbouring buildings. The assessment can compare existing and proposed conditions and identify where changes may occur.
A result outside the relevant guidance does not automatically mean a proposal is unacceptable. The findings should be considered in context, including the site location, existing conditions, scale of change and overall planning balance. Design changes or mitigation measures may also be recommended.
It is best to seek advice during the early design stage. Early assessment can identify potential constraints, test alternative layouts and help the design team reduce effects on neighbouring properties before the planning application is submitted.
Daylight studies are commonly required for developments where a proposed building could affect access to natural light for...
Daylight and Sunlight Assessments can influence the design of a development long before a planning application is submitted....
Improving daylight performance in buildings is an important part of modern architectural design. Natural light affects how spaces...