Daylight, sunlight and overshadowing studies are undertaken for impacts on neighbouring properties for a planning application, as well as assessing the quality of light within a new development.
The main assessment tests and evaluation thresholds are set out in the Building Research Establishment (BRE) document ‘Site layout planning for daylight and sunlight: A guide to good practice’ (2011). We have also seen the introduction of a new British Standard ‘EN 17037:2018 Daylight in buildings’, adopted in May 2019.
Impacts on Neighbouring Properties
We always like to attend site, review scheme proposals and provide an overview of the issues and suggested way forward. This way the client has clear guidance on risks and a strategy to move forward. With our extensive experience in the assessments, our predictions on the likely impacts allow for appraisals to be better balanced.
We undertake the detailed CAD modelling using the latest software, extracting out the Vertical Sky Component (VSC), Daylight Distribution (DD), Annual Probable Sunlight Hours (APSH) and Sun on Ground (SOG) results where appropriate. We will also assess the Average Daylight Factor (ADF) assessments where it is required.
We will work closely with architects, land surveyors and other design team members to pull together the technical assessment model as efficiently and cost effectively as possible.
Where issues arise, we will provide advice on alterations to the proposals to establish a lower risk and/or where other areas of the development might be increased. We have a great appreciation for the design process, understanding the constraints imposed by legislation and technical input from other team members, and therefore seek to provide a workable revised solution.
Once the design is frozen for submission, we produce clear and robust reports, either adopting a stand-alone format, or for more comprehensive development, provide a chapter within an environmental statement. Our aim is to provide commentary which is accessible to all, whether it be planning officials, adjoining owners or committee members. We are prepared to provide support at the planning committee, to supplement our report.
Quality of light within a new development
With our experience of the technical assessment results, we are able to review scheme proposals and provide advice on where problem areas might occur, giving advice on where alterations to the scheme might resolve an issue. Given that we have seen proposals refused solely on the daylight/sunlight within the development, it is paramount that the scheme is reviewed as soon as possible within the design process.
We can provide 3D technical assessments utilising the architect’s scheme drawings, or as we see of late, work with the Revit modelling to extract out the required test results. The appropriate tests at present are the Average Daylight Factor (ADF), Annual Probable Sunlight Hours (APSH), Sun on Ground (SOG), but with the advent of the British Standard EN 17037, the radiance assessments can also be conducted.
We can provide strategic block massing advice where the design has not been fully fixed, so as to optimise the light potential for the more detailed phases. Where the massing has been fixed, we will provide advice on room/window sizing, balcony design, as well as other strategies to maximise the daylight and sunlight potential within a scheme.
We provide detailed reports, which can either be integrated within other reports, or as a stand-alone report.