- Guide price
- £1,300–£2,450
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
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 new dormer 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 |
|---|---|
| Dormer (8 m²), GRP, scaffold | £1,300–£2,450 |
| Single garage (18 m²), EPDM rubber | £1,450–£2,600 |
| Extension (20 m²), GRP, new deck + insulation | £2,750–£4,950 |
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, bungalows with flat-roofed side extensions and dormers and 1930s semis with flat-roofed garages and kitchen extensions. 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.
Is GRP or EPDM better on a dormer roof?
GRP fibreglass is often the first choice on a dormer, because it is laid as a liquid resin over a mat and forms neat, rigid edges, corners and drip details on a small roof. It cures to a hard surface that copes with occasional foot traffic during window cleaning or maintenance.
EPDM rubber works well on a plain rectangular dormer and can usually be laid as one sheet, with no field joins. Unlike GRP, it does not depend on resin curing conditions on the day. Torch-on felt can be used, but working a torch close to timber cladding, fascias and tiles needs extra care, so a cold-applied system is often chosen instead.
We recommend the system after surveying the dormer, its edges and how it meets the main roof.
Why is scaffold and tile detailing so important on a dormer?
Because a dormer roof is high, small and surrounded by a pitched tiled roof, most failures happen at the edges rather than in the middle. Safe access is what allows those edges to be done properly.
Ladders alone do not give a safe working platform at that height, and every roof is treated as fragile until a competent person confirms otherwise. Scaffold with edge protection lets the team work along the front and sides of the dormer, and reach the junction with the main roof.
The back of the dormer is where most leaks start. The new membrane has to turn up under the tiles or slates, with a flashing that sheds water over it. Where the old detail used lead, we reinstate or replace it. Small roofs also leave little room for error at the drip edge: the front trim must throw water clear of the window frame and fascia, and any gutter has to be big enough for the area it drains. Dormer cheeks with tile hanging or cladding are checked for gaps that let water behind.
If you are also planning insulation upgrades or work on the main roof, tell us at survey so the scaffold can be shared.
Which towns in Rhondda Cynon Taf do we cover?
Dormer roofs 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 new dormer roof cost in Rhondda Cynon Taf?
£1,300–£2,450 for an 8 m² GRP dormer roof including scaffold, at Wales guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which postcode areas do you cover in Rhondda Cynon Taf?
All of Rhondda Cynon Taf, including the CF postcode areas. Send your full postcode and we'll confirm.
How long does a GRP dormer roof last?
As an indicative range, GRP lasts 20–40 years with good specification and maintenance.
Can you replace the lead on my dormer at the same time?
Yes, where lead forms part of the dormer abutment or cheek flashings, we include renewing it in the roof job.
Why does my dormer leak at the back where it meets the roof?
That junction is the most common leak point, usually because the upstand or flashing under the tiles has failed. A proper re-roof rebuilds it.
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