EPDM rubber is flexible, seamless on most domestic roofs and very long-lasting (Firestone quote up to 50 years for RubberCover). GRP fibreglass cures into a rigid, seamless, hard-wearing surface — best for balconies and walk-on roofs. Torch-on felt is the most budget-friendly and well suited to garages and outbuildings. All three perform well when installed on a sound, dry deck.
EPDM rubber roofing
EPDM is a synthetic rubber membrane. On most domestic roofs it's laid as a single sheet, so there are no seams. It stays flexible in frost and heat, copes well with building movement, and is quick to install. We use Firestone RubberCover, which the manufacturer rates for a life expectancy of up to 50 years.
- Best for: extensions, garages, dormers, roofs with lanterns
- Strengths: seamless, flexible, long life, low maintenance
- Watch-outs: not ideal for heavy foot traffic without protection
GRP fibreglass roofing
GRP (glass reinforced plastic) is built up from resin and glass-fibre matting that cures into one rigid, seamless layer with a coloured topcoat. It's very hard-wearing and gives a crisp finish with moulded trims.
- Best for: balconies, walkways, dormers, modern extensions
- Strengths: rigid, seamless, walkable, smart finish
- Watch-outs: needs dry weather to install and a very stable deck
Torch-on felt roofing
Modern felt systems use multiple layers bonded together, finished with a mineral cap sheet. They're a big improvement on the old single-layer felt you see on sheds.
- Best for: garages, outbuildings, budget-conscious projects
- Strengths: proven, cost-effective, easy to repair
- Watch-outs: shorter life than EPDM or GRP
Which should you choose?
Choose EPDM for a long-lasting, low-maintenance roof on an extension or garage. Choose GRP where the roof will be walked on or you want a rigid, modern finish. Choose felt where budget matters most, or for outbuildings. Whatever the system, the most important factor is a sound, dry deck and proper detailing at edges, upstands and outlets.
Should the old roof be stripped?
In almost every case, yes. Stripping the old covering lets the roofer check and replace rotten timber and lay a fresh deck. Covering over an old, wet deck traps problems underneath.
Frequently asked questions
Which flat roof lasts the longest?
EPDM and GRP generally outlast felt. Firestone rates RubberCover EPDM for a life expectancy of up to 50 years when properly installed.
Which flat roof is cheapest?
Torch-on felt is usually the most budget-friendly, followed by EPDM and GRP — but prices depend on size, access and the condition of the deck.
Can a flat roof be insulated at the same time?
Yes. A "warm roof" adds insulation boards above the deck under the new covering — a good time to improve energy efficiency.
Owner of DG Roofing Services, roofing across Darlington and the North East for 30+ years. Rated 10/10 on Checkatrade from 500+ reviews.
