- Price per m²
- £79–£147
- Typical life
- 20–40 years
- Manufacturer guarantees
- 20–25 year material warranties on specified systems
- Typical garage roof
- £1,850–£3,400
Cambridgeshire at a glance
- Largest towns
- Peterborough, Cambridge, Wisbech, St Neots
- Postcode areas
- CB, PE
- Building control
- Peterborough City Council, Cambridge City Council, Fenland District Council and 2 other councils
- Neighbouring areas
- Northamptonshire · Bedfordshire · Hertfordshire · Suffolk
- Guide price region
- East of England (+5% on West Midlands rates)
How much does a GRP fibreglass roof cost in Cambridgeshire?
Guide prices including VAT at East of England 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 | £3,150–£5,650 |
| Dormer (8 m²), GRP, scaffold | £1,450–£2,800 |
| Single garage (18 m²), GRP fibreglass | £1,850–£3,400 |
| Single garage (18 m²), EPDM rubber | £1,700–£2,950 |
| Extension (20 m²), EPDM, new deck + insulation | £2,950–£5,150 |
Which flat roofs are common in Cambridgeshire?
Flat roofs in Cambridgeshire sit on terraced streets with flat-roofed rear kitchens and bathrooms, bungalows with flat-roofed side extensions and dormers and low-rise post-war blocks of flats. The East of England is the driest part of Britain, with parts of the Anglian region around 630 mm a year, so summer heat and UV, not rainfall, do most of the ageing on a felt roof. 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 Cambridgeshire the application goes to Peterborough City Council, Cambridge City Council, Fenland District Council and 2 other councils. More on the rules.
Is GRP better than EPDM, felt or a liquid roof?
GRP is the better choice when you want a rigid, walkable finish, a neat look on a visible roof, or crisp moulded details on a complicated shape. It is not automatically better on a plain garage that nobody steps on.
Strengths: hard surface that takes occasional foot traffic; jointless finish with no laps; trims, kerbs and upstands moulded as part of the roof; choice of topcoat colours; small repairs can be laminated in.
Weaknesses: sensitive to weather while laying; rigid, so it can crack where the structure moves; usually needs a new deck; styrene smell during application; skill-dependent, so workmanship matters more than with sheet systems.
For a simple roof, EPDM rubber is often quicker to lay and more forgiving of movement. Torch-on felt is usually cheaper per square metre. A liquid-applied roof can go over a sound existing surface, larger commercial roofs tend to suit single-ply, and older buildings may already have mastic asphalt worth keeping. The EPDM vs GRP vs felt guide compares the three most common choices.
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.
Which towns in Cambridgeshire do we cover?
GRP fibreglass roofing in Cambridgeshire: questions
Which towns in Cambridgeshire do you cover?
All of Cambridgeshire. 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 Cambridgeshire?
£3,150–£5,650 for a 20 m² extension roof in GRP with a new deck and insulation, at East of England guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which council handles building control for a flat roof in Cambridgeshire?
It depends on where the roof is: in Cambridgeshire that's Peterborough City Council, Cambridge City Council, Fenland District Council and 2 other councils. 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. We confirm which applies at the survey.
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.
What colours does a GRP roof come in?
Topcoats are typically available in greys, greens, black and some other shades. Lighter colours absorb less heat, and an anti-slip finish can be added where people will walk on the roof.
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