- Guide price
- £750–£1,300
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Dorset at a glance
How much does a porch or bay roof cost in Dorset?
Guide prices including VAT at South West rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Porch or bay (4 m²), EPDM | £750–£1,300 |
| 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 Dorset?
Flat roofs in Dorset sit on 1930s semis with flat-roofed garages and kitchen extensions, lock-up garage blocks on estates and newer estates where the first extension roofs are now being replaced. 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 Dorset the application goes to BCP Council and Dorset Council. More on the rules.
Do I need permission to re-roof a porch or bay?
Usually not. Re-covering a porch or bay roof without materially changing how it looks does not normally need planning permission, and an unheated open porch is not usually a thermal element.
The picture changes if the bay or porch is part of a heated room: replacing most of the roof can then bring it under the insulation rules for renovated roofs, which may need building control approval in England, a check in Wales, building standards in Scotland or district council building control in Northern Ireland. On a very small roof, adding insulation may not be technically feasible because of the height available below the window sill above. We assess that at survey.
Listed buildings need consent for changes that affect their character, and conservation areas can restrict changes to the front of a house. See our building regulations page for more detail.
How long does a porch roof replacement take?
Most porch and bay roofs are replaced in a single day, weather permitting. GRP or liquid systems may need a return visit for a topcoat once the first coat has cured.
Disruption is minimal. You may need to use another door while a front porch is being re-roofed, and the area below should be kept clear for safety. A ground-floor bay can usually be reached from a tower or platform steps, while a first-floor bay may need a small scaffold. The window below stays usable, though it is best kept closed while resin is curing.
Which towns in Dorset do we cover?
Porch, bay and canopy roofs in Dorset: questions
Which towns in Dorset do you cover?
All of Dorset. 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 porch or bay roof cost in Dorset?
£750–£1,300 for a small 4 m² porch or bay roof in EPDM, 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 Dorset?
All of Dorset, including the BH, DT postcode areas. Send your full postcode and we'll confirm.
Can a canopy over a front door be re-covered?
Yes. Small canopies are re-covered in the same way as porches, usually in EPDM or GRP, subject to the minimum charge.
Can a bay window roof be replaced without scaffold?
A ground-floor bay usually can, using a tower or platform. A first-floor bay generally needs a small scaffold for safe access.
Why is my porch roof leaking when the felt looks fine?
The water is often coming from the wall junction, not the roof surface. A failed flashing, cracked mortar or porous brick above can let water in behind the upstand.
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