- Guide price
- £1,550–£2,900
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Hampshire at a glance
- Largest towns
- Southampton, Portsmouth, Basingstoke, Gosport
- Postcode areas
- BH, GU, PO, RG, SO, SP
- Building control
- Southampton City Council, Portsmouth City Council, Basingstoke and Deane Borough Council and 10 other councils
- Neighbouring areas
- Isle of Wight · Berkshire · West Sussex · Surrey
- Guide price region
- South East (+10% on West Midlands rates)
How much does a new dormer roof cost in Hampshire?
Guide prices including VAT at South East rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Dormer (8 m²), GRP, scaffold | £1,550–£2,900 |
| Single garage (18 m²), EPDM rubber | £1,750–£3,100 |
| Extension (20 m²), GRP, new deck + insulation | £3,300–£5,900 |
Which flat roofs are common in Hampshire?
Flat roofs in Hampshire sit on 1930s semis with flat-roofed garages and kitchen extensions, bungalows with flat-roofed side extensions and dormers and terraced streets with flat-roofed rear kitchens and bathrooms. Much of the South East sits in the drier Thames catchment at roughly 730 mm of rain a year, so the usual failures are at joints, upstands and outlets rather than from sheer volume of rain. 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 Hampshire the application goes to Southampton City Council, Portsmouth City Council, Basingstoke and Deane Borough Council and 10 other councils. 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 Hampshire do we cover?
- Southampton
- Portsmouth
- Basingstoke
- Gosport
- Waterlooville
- Farnborough
- Eastleigh
- Winchester
- Havant
- Andover
- Fareham
- Aldershot
- Fleet
- Totton
- New Milton
- Bordon
- Hythe
- Yateley
- Alton
- Emsworth
- Hedge End
- Romsey
- Hayling Island
- Tadley
Dormer roofs in Hampshire: questions
Which towns in Hampshire do you cover?
All of Hampshire. 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 Hampshire?
£1,550–£2,900 for an 8 m² GRP dormer roof including scaffold, at South East 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 Hampshire?
It depends on where the roof is: in Hampshire that's Southampton City Council, Portsmouth City Council, Basingstoke and Deane Borough Council and 10 other councils. 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. We confirm which applies at the survey.
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.
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.
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.
Everything about dormer roofs → · All flat roofing in Hampshire →