EPDM vs Felt vs GRP: Which Flat Roof Is Best?
Honest pros, cons, lifespan and cost of the three most common flat roof systems used on Essex garages, extensions and dormers.
If your garage, extension or dormer roof has started to bubble, crack or leak, you'll quickly find yourself choosing between three flat-roof systems: traditional felt, EPDM rubber, or GRP fibreglass. Here's a plain-English comparison of how they actually perform in Essex weather.
Traditional felt (built-up bitumen)
Felt is the cheapest option upfront and what most older houses already have. A modern three-layer torch-on felt system lasts 10–15 years. The downsides: it cracks in heat, blisters in sun, and patches show every time it's been repaired. We still install it occasionally on tight budgets, but it's no longer our first recommendation for a roof you want to forget about.
EPDM rubber
EPDM is a single sheet of synthetic rubber laid in one piece across the whole roof. No joins, no seams to fail. It flexes with temperature changes, doesn't crack, and has a realistic lifespan of 30–50 years. Maintenance is essentially zero — sweep the leaves off and forget about it. It's our most-installed flat roof system across Essex.
GRP (glass-reinforced plastic / fibreglass)
GRP gives you a hard, seamless, walk-on surface that looks closer to a tiled finish. Expected lifespan is 25–30 years. It's an excellent choice for balconies, walkways and any flat roof that will see foot traffic. The catch: it must be installed in dry conditions over completely dry timber, otherwise it can fail early. Done properly, it's brilliant.
Quick comparison
- •Cheapest upfront — Felt (~£60–£90/m²)
- •Best value over 30 years — EPDM (~£90–£130/m²)
- •Best for walk-on / visible finish — GRP (~£100–£140/m²)
- •Longest lifespan — EPDM (30–50 years)
- •Lowest maintenance — EPDM
Our recommendation
For 90% of garage and extension roofs in Essex we recommend EPDM. It's the best balance of price, lifespan and reliability. GRP wins if it's a roof you'll walk on. Felt only wins on absolute lowest budget for a short-term fix.
Want a free flat roof quote? Call 07928 888913 and we'll measure up and price all three options so you can choose.
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