- Guide price
- £1,300–£2,450
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Carmarthenshire at a glance
- Largest towns
- Llanelli, Ammanford, Carmarthen, Burry Port
- Postcode areas
- SA
- Building control
- Carmarthenshire County Council
- Neighbouring areas
- Swansea · Neath Port Talbot · Bridgend · Rhondda Cynon Taf
- Guide price region
- Wales (−8% on West Midlands rates)
How much does a new dormer roof cost in Carmarthenshire?
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 Carmarthenshire?
Flat roofs in Carmarthenshire sit on 1960s and 1970s link-detached houses with flat-roofed garages and porches, newer estates where the first extension roofs are now being replaced and lock-up garage blocks on estates. 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 Carmarthenshire the application goes to Carmarthenshire County Council. More on the rules.
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.
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.
Which towns in Carmarthenshire do we cover?
Dormer roofs in Carmarthenshire: questions
Which towns in Carmarthenshire do you cover?
All of Carmarthenshire. 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 Carmarthenshire?
£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 council handles building control for a flat roof in Carmarthenshire?
It depends on where the roof is: in Carmarthenshire that's Carmarthenshire County 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.
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.
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.
How long does a GRP dormer roof last?
As an indicative range, GRP lasts 20–40 years with good specification and maintenance.
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