The methodology behind UK planning daylight and sunlight assessment — BRE 209, rights of light, shadow, townscape — written plainly, with worked examples.
The technical library sits alongside our procedural guides and case studies. Each piece defines one concept, gives the calculation method, cites the primary guidance, and shows how a resident can challenge the metric in an objection. Terms in these pieces are also defined in the planning glossary.
The primary BRE 209 metric for daylight impact. The 27% absolute threshold, the 0.8 ratio test, worked example, and how to challenge a VSC calculation in a planning objection.
The BRE 209 sunlight metric, the 25% annual and 5% winter thresholds, and the 0.8 ratio rule for sunlight loss.
How the BRE contour test differs from VSC, when it matters, and how to read NSL plans in a daylight and sunlight report.
The historic complementary tests for overshadowing and privacy. Where they are still used and how they relate to BRE methodology.
How the Waldram projection encodes sky geometry, and the role of the 0.2% sky factor (the Waldram test) in the law of rights of light.
The critical distinction between the planning metric (BRE 209, CIE sky) and the legal easement (Prescription Act 1832, 0.2% sky factor).
Structure of a typical report, which tables to read first, and the receptor-schedule errors that appear most frequently.
Why 21 March is the benchmark for overshadowing of amenity space, and how the BRE APSH open-space test is applied.
Hit The Roof reads the developer's BRE 209 report and runs an independent shadow and daylight model for the homes it affects.
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