- Price per m²
- £69–£129
- Typical life
- 20–40 years
- Manufacturer guarantees
- 20–25 year material warranties on specified systems
- Typical garage roof
- £1,650–£3,000
Rhondda Cynon Taf at a glance
- Largest towns
- Rhondda, Tonypandy, Pontypridd, Aberdare
- Postcode areas
- CF
- Building control
- Rhondda Cynon Taf County Borough Council
- Neighbouring areas
- Merthyr Tydfil · Caerphilly · Bridgend · Blaenau Gwent
- Guide price region
- Wales (−8% on West Midlands rates)
How much does a GRP fibreglass roof cost in Rhondda Cynon Taf?
Guide prices including VAT at Wales 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 | £2,750–£4,950 |
| Dormer (8 m²), GRP, scaffold | £1,300–£2,450 |
| Single garage (18 m²), GRP fibreglass | £1,650–£3,000 |
| Single garage (18 m²), EPDM rubber | £1,450–£2,600 |
| Extension (20 m²), EPDM, new deck + insulation | £2,600–£4,500 |
Which flat roofs are common in Rhondda Cynon Taf?
Flat roofs in Rhondda Cynon Taf sit on newer estates where the first extension roofs are now being replaced, lock-up garage blocks on estates and terraced streets with flat-roofed rear kitchens and bathrooms. Wales averages roughly 1,460 mm of rain a year, among the wettest in Britain, so we design for steady run-off: proper falls, clear outlets and upstands well above the finished roof. Approximate 1991–2020 regional averages based on Met Office data.
Building regulations in Wales
Welsh guidance is that most re-roofing needs building control approval, so it's worth checking whenever more than a quarter of a roof is replaced or repaired. Renovated roofs are upgraded to around 0.16 W/m²K where feasible, and new extension roofs are built to 0.13 W/m²K under the Welsh Approved Document L. In Rhondda Cynon Taf the application goes to Rhondda Cynon Taf County Borough Council. More on the rules.
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.
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.
Which towns in Rhondda Cynon Taf do we cover?
GRP fibreglass roofing in Rhondda Cynon Taf: questions
Which towns in Rhondda Cynon Taf do you cover?
All of Rhondda Cynon Taf. 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 Rhondda Cynon Taf?
£2,750–£4,950 for a 20 m² extension roof in GRP with a new deck and insulation, at Wales 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 Rhondda Cynon Taf?
It depends on where the roof is: in Rhondda Cynon Taf that's Rhondda Cynon Taf County Borough Council. Welsh guidance is that most re-roofing needs building control approval, so it's worth checking whenever more than a quarter of a roof is replaced or repaired. 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.
How long before a new GRP roof is fully cured?
The topcoat is usually touch-dry within hours in reasonable weather, but full cure takes longer in cold conditions. We advise keeping off the roof until the team confirms it is ready.
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