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Dormer roofs across Bristol

Guide prices for a typical GRP dormer roof in Bristol, including scaffold, are shown on this page. The final figure depends on the size of the dormer, the scaffold needed, insulation, deck condition and the detailing where it meets the main roof. The fixed price follows a free, no-obligation survey.

Rear box dormer with a grey GRP flat roof and anthracite cladding on a Victorian terraceComputer-generated example image
Guide price
£1,450–£2,750
Survey
Free for new and replacement roofs
Quote
Fixed, in writing
Coverage
England, Wales, Scotland, NI

Bristol at a glance

Largest towns
Bristol
Postcode areas
BS
Building control
Bristol City Council
Neighbouring areas
Somerset · Gloucestershire · Wiltshire · Herefordshire
Guide price region
South West (+3% on West Midlands rates)

How much does a new dormer roof cost in Bristol?

Guide prices including VAT at South West rates. The fixed price comes after a free survey for new and replacement roofs.

JobGuide price inc VAT
Dormer (8 m²), GRP, scaffold£1,450–£2,750
Single garage (18 m²), EPDM rubber£1,650–£2,900
Extension (20 m²), GRP, new deck + insulation£3,100–£5,550

Which flat roofs are common in Bristol?

Flat roofs in Bristol sit on low-rise post-war blocks of flats, bungalows with flat-roofed side extensions and dormers and 1960s and 1970s link-detached houses with flat-roofed garages and porches. The South West averages roughly 1,260 mm of rain a year and many roofs face wind off the Atlantic, so we specify fixings and edge details for wind uplift as well as drainage. 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 Bristol the application goes to Bristol City 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.

How long does a dormer roof replacement take?

The roofing itself typically takes one to three days, with scaffold going up before and coming down after. Allow a few extra days overall for the scaffold.

The room under the dormer stays usable, though it will be noisy during the strip-out, and dust can fall through gaps around the ceiling. Moving furniture away from the window helps. Scaffold usually needs space on the drive or garden, and sometimes a pavement licence. GRP has a strong smell while it cures, so keep the dormer windows shut on the day it is laid.

Which towns in Bristol do we cover?

Dormer roofs in Bristol: questions

Which towns in Bristol do you cover?

All of Bristol. 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 Bristol?

£1,450–£2,750 for an 8 m² GRP dormer roof including scaffold, at South West guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.

Which postcode areas do you cover in Bristol?

All of Bristol, including the BS postcode areas. Send your full postcode and we'll confirm.

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.

Will insulating my dormer roof make it higher?

Yes, by the insulation thickness. We plan the build-up so the new roof still sits correctly under the main roof tiles at the back edge.

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