A straightforward comparison to help Warwickshire homeowners choose the right flat roof for their property.
If you're replacing a flat roof on a garage, extension or outbuilding, you'll likely be choosing between EPDM rubber and GRP fibreglass. Both are excellent modern alternatives to traditional felt — but they suit different situations. Here's an honest comparison.
EPDM (Ethylene Propylene Diene Monomer) is a synthetic rubber membrane that has been used in commercial roofing for decades. It comes in large sheets that are bonded to the roof deck, creating a seamless, fully waterproof surface. Brands like Firestone RubberCover have made it increasingly popular for domestic properties too.
GRP (Glass Reinforced Plastic) is a hard, rigid material applied in liquid form and allowed to cure into a solid surface. It's laid over the roof deck and finished with a gel coat that gives it a smooth, attractive appearance. GRP is the same material used to make boat hulls — it's extremely durable and fully waterproof.
| EPDM Rubber | GRP Fibreglass | |
|---|---|---|
| Lifespan | 40–50+ years | 25–30+ years |
| Cost (garage) | £800–£1,500 | £1,000–£2,000 |
| Appearance | Dark grey/black rubber | Smooth light grey |
| Foot traffic | Moderate | Excellent |
| Cold flexibility | Excellent | Good |
| Complex shapes | Good | Excellent |
| Maintenance | Very low | Low |
Choose EPDM if: you want the longest possible lifespan, you're on a tighter budget, or the roof is in a location where it won't be walked on regularly. EPDM also handles the freeze-thaw cycle better, which matters during Warwickshire winters.
Choose GRP if: you want a smarter finish, the roof will be used as a roof terrace or walked on regularly, or the roof has complex detailing (multiple angles, pipes, outlets) where the rigid material conforms and cures neatly.
Both are vastly better than traditional felt, which typically needs replacing every 10–15 years. Either choice is a long-term solution.
Our flat roofing specialists are happy to advise which is best for your specific roof — just call us on 07376 660209 for a free survey.
Free survey, honest advice on EPDM vs GRP, and a clear written quote — no pressure.
07376 660209