EPDM vs Felt vs GRP
By the Quantock Roofing team · Updated 14 June 2026
If you're replacing a flat roof, you'll come across three main systems: EPDM rubber, torch-on felt and GRP fibreglass. None is universally best — each suits different roofs. Here's how they compare in plain English.
EPDM rubber
A single rubber membrane that can cover many roofs in one piece, so there are very few joints to fail. It's flexible across temperature changes and gives a neat, low-profile finish. A strong all-rounder for many domestic flat roofs.
Torch-on felt
A proven system built up in bonded layers for strength. Modern felt is a world away from the cheap single-layer roofs of the past — robust, cost-effective and good around complex detailing. It involves hot works, so there are sometimes restrictions near combustible details.
GRP fibreglass
A seamless, hard-wearing finish with no joints across the main area and a neat, solid feel — good for balconies and visible roofs. It needs a sound, dry deck and suitable weather to cure, and is less forgiving of movement than a membrane.
How to choose
The right choice depends on the roof structure, the detailing, how the roof is used and your budget — not on which system is 'best' in the abstract. We inspect the roof first, then recommend honestly. All three carry a 10-year workmanship guarantee when we install them.
