Flat roofs earned their bad reputation in the era of two-layer mineral felt, which cracked, blistered and gave up after ten years. Modern coverings are a different proposition entirely — a single-ply EPDM rubber membrane or a properly laid GRP fibreglass system will outlast most pitched-roof repairs. We install and repair flat roofs on extensions, dormers, garages, porches and outbuildings across Mansfield and Nottinghamshire.
EPDM rubber
EPDM is a synthetic rubber membrane laid in a single piece over the whole roof, which means there are no seams across the field of the roof for water to find. It stays flexible in cold weather, tolerates the movement a timber deck makes through the seasons, and is unaffected by UV. On a garage or extension roof it is usually the most cost-effective long-term choice, and manufacturers typically guarantee the membrane for 20 years while expecting considerably more. It is our default recommendation for most domestic flat roofs.
GRP fibreglass
GRP is laid wet — fibreglass matting saturated with resin and topped with a pigmented topcoat — so it cures into one seamless, rigid, slightly textured surface bonded to the deck. It handles foot traffic better than rubber, takes a proper trim detail neatly, and suits balconies, dormer cheeks and anything that will be walked on. It needs dry conditions and a correct deck to go down properly, which is exactly where cut-price fibreglass jobs fail.
Falls, outlets and the things that actually cause leaks
A flat roof is not flat. It needs a fall of at least 1:80 after deflection so water runs to an outlet instead of ponding in the middle, and most failed flat roofs we are called to have either no fall at all or an outlet that was never big enough. Where the existing deck has no fall we build one in with firrings before the covering goes on. Upstands at abutments need to be high enough, outlets need to be sized and sited to actually take the water, and the drip edge needs a proper trim rather than a smear of mastic. Get those three details right and the covering does the easy part.
What is included
- EPDM rubber single-ply membrane — seamless over the field
- GRP fibreglass for balconies and trafficked areas
- High-performance torch-on felt systems
- New decks and firrings to create proper falls
- Outlets, upstands, trims and abutment detailing
- Insulated warm-roof build-ups for habitable spaces
What it costs, roughly
We quote a fixed price in writing after looking at the job, because roofs vary far more than price lists admit. That said, people reasonably want a ballpark before they pick up the phone, so our roofing price guide sets out real indicative figures for every service we offer, including this one. No registration, no "prices from" that nobody has ever actually paid.