EPDM rubber, GRP fibreglass and high-performance felt flat roofs across Somerset. We diagnose ponding and leaks properly, get the falls right, and detail the upstands so the roof lasts its design life — not five years.
Most failed flat roofs we strip in Somerset don't fail because of the membrane — they fail because of three things underneath: poor falls causing ponding water, bad detailing where the flat meets a wall, chimney or pitched roof, and aging decks that should have been replaced rather than re-covered.
We survey for those three before quoting. If the deck needs replacing, we say so. If the falls need re-grading with tapered insulation, that's in the price. The membrane choice (EPDM, GRP or felt) comes last — it's the smallest variable.
All three are valid. The right call depends on the size, shape and number of upstands on your roof, plus your budget and how long you want to leave it alone.
Lifespan: 25–50 years
Medium and large flat roofs with few upstands — extensions, garages, large dormers.
Cost note: Usually the best value per m² on roofs over ~15 m².
Lifespan: 20–30 years
Smaller flat roofs with multiple edges and upstands — bay windows, porches, complex dormers.
Cost note: Usually a strong choice on roofs under ~15 m² with several details.
Lifespan: 15–25 years
Tighter budgets, sheds and outbuildings, like-for-like replacement of existing torch-on felt.
Cost note: Best where budget is the deciding factor and the deck is sound.
If you recognise any of these on your roof, the fix is rarely a sealant tube — but it's rarely a full strip either. Honest diagnosis first.
Cause: Insufficient fall to the outlet — usually a build-up of old felt layers or a sagging deck.
Proper fix: Strip back to deck, fit tapered insulation or re-grade the deck, then install new membrane.
Cause: Moisture trapped between layers, expanding in summer heat.
Proper fix: Don't patch — strip and replace. Patches buy you a season at best.
Cause: Aged adhesive failure or building movement that wasn't allowed for at the join.
Proper fix: Local repair on EPDM is reliable; on felt it usually signals end-of-life and a full replacement.
Cause: No expansion allowance where the flat meets a pitched wall or chimney.
Proper fix: Cut out, re-lay with proper expansion detail and re-finish in matching topcoat.
Cause: Failed lead apron or missing soaker — water tracks under the tiles, drips through the flat.
Proper fix: Re-dress lead in Code 5, properly chase into the brickwork, then re-bond the membrane up the upstand.
Cause: Aluminium drip trims lift in wind if not bedded into the membrane correctly.
Proper fix: Re-fit edge trim with proper bonding, refresh sealant at the fascia line.
We cover the whole county for flat roof work — extensions, garages, dormers, outbuildings and small commercial. See your town below for local detail.
It depends on size and shape. EPDM is the strongest choice for medium/large flat roofs with few details (one-piece membrane, 25+ year life). GRP suits smaller, more complex roofs with multiple upstands. Modern polymer-modified felt is the budget option where the deck is sound and the brief is like-for-like replacement.
EPDM 25–50 years, GRP 20–30 years, modern felt 15–25 years. The biggest single factor is whether the falls drain properly — a flat roof that ponds will fail well before its design life regardless of which membrane is on top.
Usually yes — most repeat leaks trace back to one of three things: failed seams, ponding from poor falls, or a bad detail where the flat meets a wall, chimney or pitched roof. We diagnose properly before quoting so you're not paying to patch the wrong area.
If you're going down to the deck, current building regs apply for any flat roof over a heated space. We quote tapered PIR insulation as standard on extension and dormer replacements — it both meets regs and helps create proper drainage falls.
We don't publish price-per-m² because deck condition, fall correction and detailing change the figure significantly. Most domestic extension roofs (10–30 m²) sit in the £1,500–£4,500 range fully installed including scaffold and skip. You get an itemised written quote before anything starts.
Yes — dormers are a regular job. The detail that matters most is the upstand where the dormer's flat roof meets the pitched main roof, and we dress that properly in Code 5 lead with the membrane bonded up the upstand rather than relying on sealant.
Yes — workshops, light-industrial units and shopfront flat roofs across Somerset. For anything over 100 m² we'd usually recommend EPDM as the most cost-effective long-life option.
Tell us what's on the roof, what's going wrong (or what's planned) and we'll arrange a free survey and a clear written quote.
