Felt Flat Roofing Replacement Cost UK

Millions of UK homes still have mineral felt flat roofs. When felt reaches the end of its life — typically after 10–20 years — it's often better to upgrade to a modern system rather than re-felt.

Cost of Like-for-Like Felt Replacement

Replacing felt with a new 3-layer mineral felt system costs approximately £35–£55 per square metre installed. For a typical garage (15m²), expect £600–£900. For a 40m² extension roof, expect £1,500–£2,200.

Cost of Upgrading to GRP or EPDM

Upgrading to GRP fibreglass or EPDM costs £60–£90 per square metre installed, roughly 50–80% more than felt. However, the dramatically longer lifespan (25–30 years versus 10–15 years) makes the upgrade financially worthwhile in most cases.

Additional Costs to Budget For

Strip and disposal of old felt: usually included. Replacement of rotten decking boards: £30–£60 per sheet of OSB/plywood. Scaffolding (if required): £400–£800 for domestic work. Insulation upgrade (if required by building control): additional £15–£30 per m².

Our Recommendation

If your felt roof is more than 10 years old and you're replacing it, we strongly recommend upgrading to GRP or EPDM. The cost difference is often less than people expect, and you'll have a roof that lasts 30+ years rather than needing attention again within a decade.