Behanllp Chartered Surveyors
Telephone: 01727 800075

Daylight and Sunlight Studies


This example of a 3D model shows the need for assessing the daylight levels to a proposed basement flat served by windows within a light well scenario.


This is a section through the basement of the property in image 1 and shows the daylight distribution contours to each room assessed. This process allows us to advise designers on the best solutions to ensure internal space is adequately naturally lit.


Here are worked examples of daylight VSC (Vertical Sky Component) Waldram Diagrams (top two viewports) and Sunlight (Annual Probable Sunlight Hours) Waldram Diagrams (bottom two viewports).


This worked example shows the daylight distribution effect a scheme will have on a neighbouring property. The magenta hatched area within each room demonstrates the light loss as a result of the proposed development in green.


Here is a further example of a four daylight VSC diagram taken at different locations around a site. The grey colour buildings show surrounding properties, the brown colour buildings show the existing mass and the red colour shows the proposed mass. This demonstrates how the sky visibility is reduced by the proposed development.


RICS Guidance Note “Daylighting and Sunlighting”
Mark Behan is a member of the working group that produced this guidance note. This guidance note provides advice to surveyors who accept instructions to advise on daylight, sunlight and shadow calculations for developments. It explains the different types of assessment available, reporting procedures and the roles that the Chartered Surveyor will need to perform.