Conservation Roof Replacement: Slate, Tile, Lead

Roof replacement on heritage-heritage-listed buildings requires materials matching the original — typically Slate, clay tile, or lead. The specification process is technical, costly, and not the place for value engineering.

Matching the original

Conservation officers will specify:

• Slate type (Welsh vs Spanish, gauge, colour)
• Tile type (handmade vs machine made, era-appropriate)
• Lead weight code
• Fixing detail (copper nails for slate, traditional wedges)
• Ridge and hip detailing
• Lime mortar bedding for ridges

Slate

Originally produced from quarries in north Wales. Long-lasting (150+ years). Premium pricing — current Slate roof: R2,800–R5,200 per m². Spanish or other slate is cheaper but rarely matches the colour and texture.

Clay tiles

Handmade clay tiles for heritage roofs typically R1,100–R2,200 per m². Variation in colour and texture is part of authenticity — machine-made uniformity is often rejected.

Lead

• Code 4 lead: small flashings, gutters
• Code 5: typical valley gutters, flashings
• Code 6+: heavier work, flat roof coverings

Lead theft remains a problem on heritage roofs — anti-theft fixings and marking now standard. Lead substitutes (LeadAx, Easy-Lead) are not accepted on heritage-heritage-listed buildings.

Underlay and insulation

Modern breathable underlays are acceptable on most heritage roofs. Insulation between rafters or above rafters can be added, subject to ventilation and condensation review. Provincial Heritage Resources Authority (PHRA) permit required for any insulation upgrade.

Cost benchmarks

• Slate roof reslate: R3,600–R5,600 per m²
• Handmade clay tile roof: R2,400–R4,000 per m²
• Lead lined valley replacement: R8,000–R16,000 per linear metre
• Hip and ridge bedding in lime mortar: R800–R1,800 per linear metre

Programme

Heritage roof works are weather-dependent and slow. Scaffold and temporary cover essential. Typical Georgian terrace re-roofing: 6–12 weeks.

MCFAR works alongside conservation roofing specialists.

Frequently Asked Questions