Flat RoofingContractors

Flat roof systems

GRP fibreglass roofing in Hounslow

Thinking about a GRP roof for a dormer or extension in Hounslow? The finish is rigid and tidy, with trims moulded into the roof rather than glued on. It does need a dry day and a new deck, so we survey first, explain what is involved and give you a fixed written quote with no obligation.

Finished grey GRP fibreglass flat roof with moulded trims on a single-storey extensionComputer-generated example image

Hounslow at a glance

Postcode districts
TW3, TW5, TW4, TW7, UB2, TW14, UB1, TW13 and 2 more
Council area
London Borough of Hounslow
Building approval
London Borough of Hounslow building control, or a registered building control approver
Guide price region
London (+20% on West Midlands rates)

Why choose GRP fibreglass roofing in Hounslow?

GRP is a good fit in Hounslow for roofs with awkward shapes, short runs of upstand and lots of corners, because every detail is laminated in place rather than cut and glued. Where a sheet membrane would need many joins, fibreglass forms one continuous skin across the whole roof.

In a town like Hounslow, flat roofs are commonly found on kitchen extensions and roof terraces behind period houses or shops with flat-roofed stores below flats above. The Thames basin is one of the drier parts of Britain at roughly 730 mm of rain a year, but summer heat is the bigger test here: dark membranes on south-facing roofs swing a long way in temperature.

How much does a GRP fibreglass roof cost in Hounslow?

At London guide rates, a 20 m² extension roof in GRP with a new deck and insulation comes to £3,600–£6,450 including VAT. The fixed price comes after a free survey for new and replacement roofs.

JobGuide price inc VAT
Extension (20 m²), GRP, new deck + insulation£3,600–£6,450
Dormer (8 m²), GRP, scaffold£1,700–£3,200
Single garage (18 m²), GRP fibreglass£2,150–£3,900
Single garage (18 m²), EPDM rubber£1,900–£3,350
Extension (20 m²), EPDM, new deck + insulation£3,350–£5,850

How long does a GRP roof last, and is it guaranteed?

A properly laid GRP roof typically lasts 20 to 40 years. The range is wide because so much depends on the laminate being fully wetted out, the deck staying dry and stable, and the topcoat being renewed if it wears.

When GRP fails early, the cause is usually one of these:

  • resin laid in damp or cold conditions that never fully cured;
  • cracks at board joints or trims where movement was not allowed for;
  • a deck that was wet, soft or poorly fixed before laminating;
  • a thin or patchy topcoat that has weathered through.

On guarantees, manufacturer material guarantees are available on many specified GRP systems, and some need a registered build-up or an approved installer. Where registration is possible, we do it for you. Every re-roof also comes with our written workmanship guarantee, with the length set out in your quote, and you can ask about insurance-backed options. Read more in our guarantees guide.

What's included?

  • Warm-roof insulation and vapour control layer where the room below is heated
  • Removal of the old covering and disposal of waste
  • Resin and glass-mat laminate with taped and reinforced joints
  • New OSB3 or plywood deck, fixed at close centres

Building regulations in England

Replacing more than half of a flat roof over a heated room usually counts as renovating a thermal element, so the roof is insulated to around 0.16 W/m²K where that's technically and economically feasible, and the work is notified to building control: the council or a registered building control approver, unless a registered competent person self-certifies it. A roof on a new extension is built to 0.15 W/m²K. Patch repairs, and most unheated detached garages, don't trigger the upgrade. Structural changes, or a new covering that adds 15% or more to the roof's weight, also need approval. More on the rules.

Which nearby areas do we also cover?

GRP fibreglass roofing in Hounslow: questions

Do you cover Hounslow?

Yes. Hounslow is part of our London coverage, including postcode districts TW3, TW5, TW4, TW7, UB2, TW14 and 4 more. Surveys and roofs are carried out by vetted roofing teams working under S&K Property Investments and Improvement Ltd.

Who checks building regulations for a flat roof in Hounslow?

Where the work needs approval it goes to London Borough of Hounslow building control, or a registered building control approver. We tell you at the survey whether your job needs it and deal with the paperwork as part of the quote.

How much does a GRP fibreglass roof cost in Hounslow?

£3,600–£6,450 for a 20 m² extension roof in GRP with a new deck and insulation, at London guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.

How long before a new GRP roof is fully cured?

The topcoat is usually touch-dry within hours in reasonable weather, but full cure takes longer in cold conditions. We advise keeping off the roof until the team confirms it is ready.

Is GRP suitable for a dormer roof?

Yes, GRP is commonly used on dormers because the trims can be moulded neatly and the finish looks tidy from the ground. Scaffold is normally needed, which we include in the quote.

Other flat roof work in Hounslow

GRP fibreglass roofing in Hounslow: get a fixed price

Free survey and a written fixed quote for replacement and new roofs. No obligation.

Call usGet a guide price