Engineering Disclaimer: Calculations and guidance provided on RoofPitchCalculator.co.uk are geometric estimates. They do not substitute for formal structural engineering calculations, site-specific wind-load appraisals under BS EN 1991-1-4, or formal Building Control Approval.
Site-Specific Considerations
Always verify final timber sizes against UK Building Regulations Approved Document A span tables or consult a qualified Chartered Structural Engineer (MIStructE/MICE) before cutting timber or ordering materials.
📚 Primary Technical Sources & British Standards
- BS 5534:2014+A2:2018: Code of practice for slating and tiling for pitched roofs and vertical cladding. British Standards Institution.
- BS 5250:2021: Management of moisture in buildings — Code of practice. British Standards Institution.
- BS 6229:2018: Flat roofs with continuously supported flexible waterproof coverings — Code of practice.
- NHBC Standards Chapter 7.2: Pitched Roofs — Minimum pitches, rafter timber sizing, batten gauges and fixing specifications.
- UK Manufacturer Technical Literature: Marley Technical Handbooks, BMI Redland Fixing Guides, CUPA Pizarras Slate Technical Manuals.
Last technical audit date: 17 August 2026.