The Cost of Flat Roof Replacement in the UK

Flat roof replacement costs vary significantly depending on the size of the roof, the system chosen, access requirements, and the complexity of the job. Here's a guide to typical costs across different systems.

Typical Cost Ranges (2026)

• Felt (bitumen) replacement: £40–£70 per m²
• EPDM rubber replacement: £60–£90 per m²
• GRP fibreglass replacement: £70–£100 per m²
• Liquid waterproofing systems: £50–£85 per m²

What Affects the Price?

• Roof size — larger roofs benefit from economies of scale
• Access — scaffolding adds cost if required
• Existing roof condition — stripping back multiple layers adds time and labour
• Insulation upgrade — adding or upgrading insulation is recommended when replacing
• Drainage work — improving falls or adding new outlets
• Location — labour costs are higher in London and the South East

Beware of Suspiciously Low Quotes

If a quote seems unusually cheap, it usually means corners are being cut — on materials, installation, or both. A flat roof installed with cheap materials or poor workmanship will fail early and cost more in the long run. Always ask for evidence of previous work and check for proper warranties.

Getting an Accurate Quote

The only way to get an accurate quote is an on-site survey. Every roof is different and there are often factors (deck condition, access challenges, drainage requirements) that can't be assessed remotely. We offer free surveys with no-obligation quotes.