- Price per m²
- £71–£133
- Typical life
- 20–40 years
- Manufacturer guarantees
- 20–25 year material warranties on specified systems
- Typical garage roof
- £1,700–£3,100
Renfrewshire at a glance
- Largest towns
- Paisley, Renfrew, Johnstone, Erskine
- Postcode areas
- PA
- Building standards
- Renfrewshire Council
- Neighbouring areas
- West Dunbartonshire · East Renfrewshire · Glasgow City · East Dunbartonshire
- Guide price region
- Scotland (−5% on West Midlands rates)
How much does a GRP fibreglass roof cost in Renfrewshire?
Guide prices including VAT at Scotland rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), GRP, new deck + insulation | £2,850–£5,100 |
| Dormer (8 m²), GRP, scaffold | £1,350–£2,500 |
| Single garage (18 m²), GRP fibreglass | £1,700–£3,100 |
| Single garage (18 m²), EPDM rubber | £1,500–£2,650 |
| Extension (20 m²), EPDM, new deck + insulation | £2,650–£4,650 |
Which flat roofs are common in Renfrewshire?
Flat roofs in Renfrewshire sit on low-rise post-war blocks of flats, terraced streets with flat-roofed rear kitchens and bathrooms and 1960s and 1970s link-detached houses with flat-roofed garages and porches. Scotland averages roughly 1,570 mm of rain a year, with the west far wetter than the east, so drainage, falls and wind uplift are part of every specification we write. Approximate 1991–2020 regional averages based on Met Office data.
Building standards in Scotland
In Scotland a building warrant is usually needed for alterations, structural work and new roofs; like-for-like repairs to a covering can be exempt. Section 6 of the technical handbooks sets a domestic roof benchmark of 0.12 W/m²K, applied as far as reasonably practicable on an existing roof. In Renfrewshire the application goes to Renfrewshire Council (building standards). More on the rules.
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 Renfrewshire do we cover?
GRP fibreglass roofing in Renfrewshire: questions
Which towns in Renfrewshire do you cover?
All of Renfrewshire. The main towns have their own pages below, and if yours isn't listed we still cover it: send your postcode and we'll confirm.
How much does a GRP fibreglass roof cost in Renfrewshire?
£2,850–£5,100 for a 20 m² extension roof in GRP with a new deck and insulation, at Scotland guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which postcode areas do you cover in Renfrewshire?
All of Renfrewshire, including the PA postcode areas. Send your full postcode and we'll confirm.
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.
Can you walk on a GRP roof?
Yes, a correctly laid GRP roof takes occasional foot traffic, such as cleaning windows or maintaining plant. For a regular walkway or terrace, an anti-slip topcoat and a suitable specification are needed.
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.
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