Every roof in the UK must comply with The Building Regulations 2010 (as amended) enforced by your local Building Control Authority. Whether you’re building new or replacing an existing roof, here’s what the law requires.
Key Building Regulations for British Roofs
1. Approved Document A: Structure
Requirement: Roof must safely carry dead loads (its own weight) and live loads (snow, wind, foot traffic).
What this means:
- Timber sizing must follow Eurocode EN 1995-1-1
- Wind load calculations based on location (coastal vs inland)
- Snow load assumptions (typically 0.6 kN/m² for UK)
✅ Compliance: Structural engineer sign-off for complex roofs (timber trusses, large spans).
Source: Approved Document A: Structure (2013 edition)
2. Approved Document 7: Materials and Workmanship
Requirement: Roofing materials must be fit for purpose and durable.
What this means:
- Slates/tiles must meet BS EN standards (British/European Standards)
- Underlays must be breathable (prevent condensation)
- Flashings must be lead, zinc, or approved alternatives
✅ Compliance: Use CE-marked or UKCA-marked products with manufacturer warranties.
Source: Approved Document 7: Materials and Workmanship (2018 edition)
3. Approved Document L: Conservation of Fuel & Energy
Requirement: Roof insulation must achieve minimum U-values (heat loss rating).
Current Standards (2026):
- Pitched roofs: U-value ≤ 0.16 W/m²K
- Flat roofs: U-value ≤ 0.16 W/m²K
- Rafter insulation: May require external insulation to meet standard
✅ Compliance: EPC assessor inspection for new builds/extensions.
Source: Approved Document L: Conservation of Fuel and Power (2021 edition incorporating 2023 amendments)
4. Approved Document B: Fire Safety
Requirement: Roof coverings must resist external fire spread.
What this means:
- Slates, tiles, metal = compliant (Class A roof coverings)
- Some membranes require fire-rated underlays
- Thatch roofs have special requirements
✅ Compliance: Check manufacturer fire rating certificates.
Source: Approved Document B: Fire Safety (2019 edition with 2020 amendments)
5. Approved Document M: Access to and Use of Buildings
Requirement: Roof access (e.g., for maintenance) must be safe.
What this means:
- Flat roofs on apartments: Permanent access hatches required
- Pitched roofs: Safe access for chimney/valley cleaning
- Guard rails: Required if roof is accessible workspace
✅ Compliance: Relevant for commercial buildings, multi-unit developments.
Source: Approved Document M: Access to and Use of Buildings (2015 edition with 2016 amendments)
When Do You Need Planning Permission?
Most like-for-like roof replacements don’t need planning permission, but you DO need it for:
- Changing roof pitch or height significantly
- Adding roof windows/dormers in conservation areas
- Listed buildings
- Properties where permitted development rights have been removed
📋 Always check with your local planning authority before starting work.
Source: Planning Portal - Roofing
Do Reroofing Projects Need Building Control?
Yes, if you’re:
- Changing roof structure (removing load-bearing walls)
- Adding insulation that affects fire/ventilation performance
- Building a new extension with a roof
- Replacing more than 25% of roof covering
No, if you’re:
- Replacing slates/tiles on existing structure (repairs only)
- Repairing flashings or valleys
- Cleaning/repointing ridge tiles
⚠️ When in doubt, submit a “Building Notice” or “Full Plans Application” to your local Building Control Authority before work starts.
Source: The Building Regulations 2010 (as amended)
FAQ: British Roof Building Regulations
Q: Do I need an engineer for a roof replacement?
A: Not usually, unless you’re changing the structure (e.g., removing a supporting wall, increasing span). Like-for-like slate/tile replacement doesn’t require structural calculations.
Q: What insulation thickness do I need in 2026?
A: To meet the 0.16 W/m²K standard (Approved Document L 2021), you typically need 300mm of mineral wool in a pitched roof or 150mm PIR insulation in a flat roof. Your roofer or energy assessor should calculate this based on your specific roof design.
Q: Can I use reclaimed slates?
A: Yes, but they must be in good condition. Building Control may inspect for compliance with Part D (durability). Natural slate is generally acceptable.
Q: Do I need an EPC certificate after reroofing?
A: Only if you’re building a new dwelling or making a “major renovation” (>25% of building envelope). Standard re-roofing doesn’t trigger a new EPC requirement for existing homes, though improving insulation may improve your existing EPC rating.
How to Ensure Compliance
- Hire certified roofers – Competent Person Scheme members or FMB (Federation of Master Builders) members follow industry best practices
- Request certificates – Insulation U-value calculations, material CE/UKCA marks
- Keep records – Building Control may inspect during and after work
- Use approved products – Check manufacturer certifications and British/European Standards compliance
Need a roofer who understands UK Building Regulations? Get quotes from verified professionals
Official Sources
- The Building Regulations 2010 (as amended) – legislation.gov.uk/uksi/2010/2214
- Approved Documents (Parts A, B, L, M, 7) – gov.uk/government/collections/approved-documents
- Building Control Guidance – gov.uk/building-regulations-approval
- Planning Portal – planningportal.co.uk
- Energy Saving Trust – energysavingtrust.org.uk
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