Roof Replacement Cost Calculator

A full roof replacement on a typical UK semi-detached house (approx. 50–70m²) costs £4,500–£9,000 for concrete or clay plain tiles. Larger detached properties (80–120m²) cost £7,000–£15,000. Slate and natural stone are 30–50% more expensive than concrete tiles due to material and laying time. Flat roof replacements (EPDM or felt) typically cost £1,500–£5,000 depending on size and specification.

Key cost drivers include: roof area (m²), pitch and complexity (hips, valleys, dormers add cost), material choice (concrete tile, clay, slate, EPDM, GRP), scaffolding requirements, disposal of old materials, timber repairs needed, and regional labour rates. A roof requiring significant felt and batten replacement on top of tiling will cost 20–40% more than a simple strip-and-relay job.

A standard semi-detached house roof replacement takes 3–5 days for a two-person crew. Larger detached properties take 5–10 days. Complex roofs with multiple hips, valleys, or dormers take longer. Factor in 1–2 days for scaffolding erection and removal on top of the roofing work itself.

Like-for-like roof replacements in the same material do not require planning permission in most cases. However, if you're changing the material (e.g. from concrete to natural slate) or altering the roof profile, you may need permitted development consent or planning approval — especially in conservation areas or on listed buildings. Always check with your local planning authority.

Measure the total roof area in m² (ground floor footprint × pitch factor: 1.15 for a shallow pitch, 1.3 for a medium pitch, 1.5 for a steep pitch). Add 10–15% wastage for tiles. Calculate material cost from your supplier. Estimate labour days (typically 1–1.5m² per person-hour for plain tiling) and multiply by your day rate. Add scaffolding, skip, felt/battens, and your overhead and profit margin.