Insights
Factsheet: BRE 25° and 45° Rules of Thumb
Natasha Bray
Partner – Building Consultancy
31st Jul 2026
Jonathan Ray
Right to Light Surveyor, Associate Partner
This factsheet provides an overview of the BRE 25° and 45° rules of thumb used in the early stages of daylight and sunlight assessments. The tests offer an initial indication of potential impacts and help establish whether further technical assessment may be necessary.
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