- Guide price
- £1,300–£2,450
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Isle of Anglesey at a glance
- Largest towns
- Holyhead
- Postcode areas
- LL
- Building control
- Isle of Anglesey County Council
- Neighbouring areas
- Gwynedd · Conwy · Denbighshire · Flintshire
- Guide price region
- Wales (−8% on West Midlands rates)
How much does a new dormer roof cost in Isle of Anglesey?
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 Isle of Anglesey?
Flat roofs in Isle of Anglesey sit on terraced streets with flat-roofed rear kitchens and bathrooms, lock-up garage blocks on estates and bungalows with flat-roofed side extensions and dormers. 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 Isle of Anglesey the application goes to Isle of Anglesey 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.
Do I need building regulations approval for a dormer roof?
Usually, yes, if you are replacing most of the roof. A dormer roof sits over a heated room, so it counts as a thermal element, and renovating more than half of it normally means upgrading the insulation where feasible.
In England the renovation target is 0.16 W/m²K for homes, approved through building control or a competent person scheme. Wales usually needs approval for most re-roofing work. Scotland works through the council's building standards and, where required, a building warrant. Northern Ireland asks you to contact district council building control before starting.
Insulating above the deck raises the roof slightly. On a dormer, that extra height has to fit under the main roof tiles at the back edge, so the build-up is planned at survey. Re-covering a dormer that looks the same afterwards does not usually need planning permission, but a listed building or conservation area may bring extra controls. More on our building regulations page.
Which towns in Isle of Anglesey do we cover?
Dormer roofs in Isle of Anglesey: questions
Which towns in Isle of Anglesey do you cover?
All of Isle of Anglesey. 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 Isle of Anglesey?
£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 Isle of Anglesey?
It depends on where the roof is: in Isle of Anglesey that's Isle of Anglesey 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.
Is a dormer roof cheaper than a garage roof?
Not by as much as the size suggests. Scaffold and the extra detailing at height mean a small dormer roof often costs about the same as a single garage roof.
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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