EPDM and GRP are two of the most popular flat roofing systems in the UK. Both outperform traditional felt, but they suit different projects.
EPDM is a synthetic rubber membrane installed in large single sheets. It's flexible, lightweight and quick to install. For most domestic flat roofs under 50m², it's one of the most cost-effective long-life options on the market.
GRP is a wet-laid fibreglass system that cures into a rigid, seamless finish. It looks neater than EPDM, copes well with foot traffic, and is the better choice for balconies, walkways and roofs where appearance matters.
On price, EPDM is typically 10–20% cheaper to install than GRP for equivalent areas.
If the roof is hidden from view and you want the best value, EPDM is hard to beat. If the roof is visible, will be walked on, or has complex detailing, GRP is usually worth the extra investment. However, both are inferior to our liquid waterproofing application. Ultraflex is the best on the market and is suited to any flat roof.