GRP Fibreglass Roofing

GRP (glass-reinforced plastic) is laid wet as resin and glass mat over a new plywood deck, then top-coated, so it cures into one seamless skin that follows every corner, upstand and pipe. There are no joints to fail. It is tough enough to walk on, can be finished in any colour, and carries 20 to 25-year manufacturer guarantees.

The catch is that GRP must be laid on a dry, sound deck in dry weather by people who know the system. Rushed GRP on a damp deck is the source of nearly every GRP failure we are asked to look at. We schedule GRP for the forecast and never lay it on a wet deck.

Photograph: GRP Fibreglass Roofing job in progress or completed
(to be supplied)

Warning signs

Balcony or roof terraceNeeds a walkable, non-slip surface; GRP is the right system.

Dormer roofLots of edges in a small area; seamless GRP suits it.

Roof with pipes, lanterns and upstandsEach detail is simply laminated in.

Replacing a failed felt roofA GRP overlay on a new deck is a permanent answer.

Bay window roofSmall, visible and often leaking; GRP in a colour to match.

Gutter liningGRP lines concrete or timber gutters where lead would be stolen.

What we do

New GRP roofs on new 18 mm plywood or OSB3 decks
GRP overlays on existing sound decks
Walk-on and non-slip finishes for terraces
Colour-matched top coats
GRP valley and gutter linings
Warm-roof build-ups with PIR insulation beneath the deck
Edge trims, drips and upstands in matching GRP profiles

Materials and methods

Cure It or Cromar GRP systems with 450 g or 600 g chopped-strand mat, laid at the correct catalyst ratio for the temperature, and finished with a topcoat in your choice of colour. Decks in 18 mm WBP plywood or OSB3 with built-in falls of at least 1:80. Manufacturer guarantees of 20 or 25 years registered in your name.

Why choose us for grp fibreglass roofing

No seams, no joints, nothing to peel
Can be walked on, so ideal for terraces and balconies
Follows complex shapes and details
Any colour, including matching existing finishes
20 to 25-year manufacturer guarantee plus our workmanship guarantee

What to expect

We check the deck from above and, where possible, below. If it is damp or soft we replace it; GRP on a bad deck is money wasted. The roof is typically done in one to two dry days, with the topcoat applied once the laminate has cured.

Related projects

Completed project

Genuine grp fibreglass roofing projects appear here once photographed.

All projects →

Frequently asked questions

Is GRP better than EPDM?

For roofs with many details or any foot traffic, yes. For large plain roofs EPDM is cheaper and equally durable. We recommend by roof, not by preference.

Can GRP be laid over felt?

No. GRP needs a new timber deck. We strip the felt, replace any damaged boards and lay a new deck first.

Can GRP be repaired?

Yes, easily; new laminate bonds to old. Most GRP repairs are quick and permanent.

Will the roof be slippery?

Not if we fit a non-slip topcoat, which we do on any roof you will walk on.