Roof & Gutter Details
Plan area draining to gutters
Default: 75 mm/hr
5% typical
Results
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UKUK Building Regulations
References & Sources
Standards Cited
- BS EN 12056-3 — Gravity drainage systems inside buildings — Roof drainage, layout and calculation
Gutter sizing, flow capacity, and downpipe design
Formulas Used
- Required flow rate:
Q = roofArea × rainfallIntensity / 3600
Source: BS EN 12056-3 — Q in litres/second, area in m², rainfall in mm/hr - Number of brackets:
brackets = ceil(gutterRun / bracketSpacing) + 1
Source: BS EN 12056-3
Key Assumptions
- Design rainfall: 75 mm/hr for UK (BS EN 12056-3) — BS EN 12056-3
- Half-round and ogee profiles available in 75-150 mm widths — Industry standard
- Bracket spacing: 900 mm maximum — BS EN 12056-3