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Flat roof systems

GRP fibreglass roofing in Crawley

Thinking about a GRP roof for a dormer or extension in Crawley? 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

Crawley at a glance

Postcode districts
RH10, RH11
Population
about 124,008 (GeoNames)
Council area
Crawley Borough Council
Building approval
Crawley Borough Council building control, or a registered building control approver
Nearest main town
Brighton, about 20 miles
Guide price region
South East (+10% on West Midlands rates)

Why choose GRP fibreglass roofing in Crawley?

GRP is a good fit in Crawley 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 large town like Crawley, flat roofs are commonly found on lock-up garage blocks on estates or newer estates where the first extension roofs are now being replaced. Much of the South East sits in the drier Thames catchment at roughly 730 mm of rain a year, so the usual failures are at joints, upstands and outlets rather than from sheer volume of rain.

How much does a GRP fibreglass roof cost in Crawley?

Guide price in Crawley: £3,300–£5,900 for a 20 m² extension roof in GRP with a new deck and insulation, including VAT at South East rates. The fixed price comes after a free survey for new and replacement roofs.

JobGuide price inc VAT
Extension (20 m²), GRP, new deck + insulation£3,300–£5,900
Dormer (8 m²), GRP, scaffold£1,550–£2,900
Single garage (18 m²), GRP fibreglass£1,950–£3,600
Single garage (18 m²), EPDM rubber£1,750–£3,100
Extension (20 m²), EPDM, new deck + insulation£3,100–£5,350

Will a new GRP roof need extra insulation to meet building regulations?

If the roof is over a heated room and you are replacing more than half of it, usually yes. In England, Wales and Northern Ireland that counts as renovating a thermal element, and in Scotland the council's building standards service will say whether a building warrant applies.

GRP pairs well with a warm roof because the new deck boards it needs can sit on top of the insulation. The result is thicker, so we check at survey that there is room under door cills and wall flashings, and that the upstands can finish around 150 mm above the new surface. Where approval is needed we arrange it with building control or building standards.

Unheated, detached garages normally sit outside the thermal rules. See the building regulations page for each nation, or the warm vs cold roof guide for why we avoid cold roofs where we can.

What's included?

  • Resin and glass-mat laminate with taped and reinforced joints
  • Coloured UV-stable topcoat, with anti-slip finish on request
  • Removal of the old covering and disposal of waste
  • Moulded GRP trims, kerbs and upstands

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 Crawley: questions

Do you cover Crawley?

Yes. Crawley is part of our West Sussex coverage, including postcode districts RH10, RH11. 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 Crawley?

Where the work needs approval it goes to Crawley Borough Council 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 Crawley?

£3,300–£5,900 for a 20 m² extension roof in GRP with a new deck and insulation, at South East guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.

Can GRP be laid over an existing felt roof?

Generally no. GRP needs a clean, dry, rigid timber deck, so the old felt is usually stripped and the boards replaced before laminating.

Does GRP smell when it is being laid?

Yes, the resin gives off a strong styrene smell while it cures. It usually fades within a day or so, and we advise keeping nearby windows closed while the team works.

Other flat roof work in Crawley

GRP fibreglass roofing in Crawley: get a fixed price

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

Call usGet a guide price