GRP fibreglass roofing across West Sussex

Price per m²

£83–£154

Typical life

20–40 years

Manufacturer guarantees

20–25 year material warranties on specified systems

Typical garage roof

£1,950–£3,600

How much does a GRP fibreglass roof cost in West Sussex?

Guide prices including VAT at South East rates. The fixed price comes after a free survey for new and replacement roofs.

Which flat roofs are common in West Sussex?

Flat roofs in West Sussex sit on newer estates where the first extension roofs are now being replaced, 1960s and 1970s link-detached houses with flat-roofed garages and porches and 1930s semis with flat-roofed garages and kitchen extensions. 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. Approximate 1991–2020 regional averages based on Met Office data.

Building regulations in England

Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. Renovated roofs over heated rooms are insulated to around 0.16 W/m²K where that's feasible, and new extension roofs are built to 0.15 W/m²K. In West Sussex the application goes to Crawley Borough Council, Worthing Borough Council, Arun District Council and 4 other councils. More on the rules.

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.

Why do GRP roofs crack, and can weather affect the installation?

GRP usually cracks where the structure moves and the laminate cannot, typically along board joints, at the junction with trims, or where a roof meets a wall. Weather during laying is the other big factor, because resin cures by chemical reaction and that reaction is sensitive to temperature and moisture.

How we reduce the risk of cracking:

• boards fixed at close centres so the deck does not flex;
• joints taped and reinforced with an extra strip of mat;
• wall junctions finished with a separate trim or flashing, not laminated hard into the masonry;
• roofs over a certain size divided with movement details where the system calls for them.

And how weather is managed:

• no laminating in rain, on a damp deck, or when dew or frost is likely before the resin sets;
• catalyst levels adjusted for the temperature, so resin neither stays tacky on a cold day nor kicks too fast in summer heat;
• the roof sheeted over if a shower threatens a fresh laminate.

That is why a GRP date can move at short notice. A day's delay costs far less than a laminate that never cures properly.

Which towns in West Sussex do we cover?

• Crawley
• Worthing
• Bognor Regis
• Littlehampton
• Horsham
• Haywards Heath
• Chichester
• Burgess Hill
• East Grinstead
• Shoreham-by-Sea
• Lancing

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