Flat roofs on extensions, garages, dormers and outbuildings need specialist attention. We install GRP fibreglass, EPDM rubber membrane and high-performance built-up felt systems — each specified to suit the size, use and exposure of your flat roof. Every installation includes proper falls, drainage and upstand detailing.
Flat roofs on extensions, garages, dormers and outbuildings need specialist attention. We install GRP fibreglass, EPDM rubber membrane and high-performance built-up felt systems — each specified to suit the size, use and exposure of your flat roof. Every installation includes proper falls, drainage and upstand detailing.
The most common flat roof failure in West London is inadequate drainage. Original felt roofs from the 1960s-80s were often laid with insufficient fall — water pools, UV breaks down the membrane, and leaks follow. We install minimum 1:40 falls on every job using tapered insulation boards.
Before any new flat roof goes on in West London, we strip back to the deck and inspect the timber. In West London properties, we commonly find rotten timber decking from years of water ingress. Catching this before the new membrane goes down saves a callback later.
GRP fibreglass gives a seamless, rigid surface that handles foot traffic — ideal for balconies and walkable roofs. EPDM rubber is flexible, handles movement well, and comes in single sheets that eliminate seam failures. For most West London extensions under 20m², GRP is our recommendation.
Flat Roofing across West London: £800–£6,000 depending on scope, access and materials. We provide free, written, no-obligation quotes for all work. Call 0203 302 2547 for a quote.
Free quotes, no call-out fees, same-day emergency service.
📞 Call Now: 0203 302 2547"Chimney stack partial rebuild and re-render — called on a weekday and they were out within days. Professional, tidy, and the price was exactly as quoted. Highly recommend."
"Emergency roof repair after a branch came through the tiles — called on a weekday and they were out within days. Professional, tidy, and the price was exactly as quoted. Highly recommend."
"Moss removal and full roof clean — called on a weekday and they were out within days. Professional, tidy, and the price was exactly as quoted. Highly recommend."
A typical single-storey rear extension flat roof in West London costs £1,200–£3,000 depending on size and system. Garage roofs run £800–£2,000. Larger commercial or multi-section flat roofs can be £4,000–£6,000+.
GRP fibreglass lasts 30-40 years with minimal maintenance. EPDM rubber membrane lasts 25-30 years. Traditional felt typically lasts 10-15 years. We recommend GRP or EPDM for any flat roof in West London — the upfront cost is recovered many times over in lifespan.
Yes — GRP fibreglass is seamless, UV-stable, impact-resistant and lasts 2-3 times longer than felt. The only advantage felt has is lower upfront cost, which is a false economy over 20+ years.
If the membrane is sound but a localised area has failed, we can patch repair. If the membrane is blistered, cracked or ponding across more than 20% of its area, full replacement is more cost-effective.
Under current Building Regulations, any flat roof replacement must include insulation to meet thermal performance standards. We install rigid insulation boards above the deck, which also creates the correct drainage falls.
The three most common causes in West London are: ponding water from inadequate falls, membrane failure at upstands and abutments, and blocked outlets. All three are preventable with correct specification and installation.
A typical extension flat roof takes 1-2 days. Larger projects or those requiring significant deck repairs take 2-4 days. Weather-dependent — GRP cannot be laid in rain.
Flat roof installation follows a strict sequence that cannot be shortcut. Stage one: strip the existing covering and inspect the deck. Stage two: repair or replace any damaged deck timbers — rotten OSB or plywood is the most common finding on existing flat roofs. Stage three: install tapered insulation boards to create the correct drainage falls (minimum 1:40 gradient). Stage four: apply the chosen membrane system — GRP fibreglass with resin lamination, or EPDM rubber with bonded seams. Stage five: detail all upstands, drip edges and abutments. Stage six: inspect, photograph and hand over.
GRP fibreglass creates a seamless, rigid surface that handles foot traffic and resists impact — ideal for balconies, walkable roofs and areas where you need to access equipment. EPDM rubber is flexible, accommodates structural movement, and comes in single sheets up to 15m wide that eliminate seam failures. Both systems carry 25-40 year lifespans when correctly installed. We do not install traditional felt systems for new work — the lifespan is too short to justify the labour cost of installation.
All flat roof installations carry our 10-year workmanship guarantee. GRP systems additionally carry a 25-year manufacturer guarantee on the membrane when installed by an approved contractor — which we are. EPDM carries a 20-year manufacturer guarantee on the membrane. These guarantees are meaningful because both products have track records exceeding their guarantee periods.
No call-out fees. No obligation. Just an honest quote from a local West London roofer who turns up when they say they will.
0203 302 2547 📞 Call Now: 0203 302 2547