Pitched roof extensions in Swanage: design, approvals and build
Thinking about a pitched roof extension for your Swanage home? Start with a free site visit: we measure up, check what the council will allow and give you honest guide figures on the day.
- Guide price in SwanageFrom £22,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsBH19

Included in a typical project
- Roof design matched to the existing pitch and tiles
- Lead or proprietary flashings to the main wall
- Insulation to current building regulations
- Vaulted ceilings or flat ceilings with storage above
- Roof windows positioned for light and ventilation
Matching tiles is harder than it sounds. We source reclaimed or closest-match tiles where the originals are no longer made and agree samples with you before ordering.
How much does a pitched roof extension cost in Swanage?
These guide figures apply our South West England adjustment (×1.02) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Swanage: £1,890 to £3,570 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £22,500 – £26,500 | £26,000 – £34,000 | £33,500 – £43,000 |
| 4 m × 5 m 20 m² | £37,500 – £44,000 | £43,500 – £56,500 | £56,000 – £71,500 |
| 5 m × 6 m 30 m² | £56,500 – £66,000 | £65,500 – £84,500 | £84,000 – £107,500 |
For a figure based on your own dimensions, use our guide-price tool.
Local to Swanage
We cover Swanage and the postcode districts BH19. The same team covers Poole (7 miles), Bournemouth (9 miles), Christchurch (12 miles), Ferndown (14 miles), all within easy reach.
For homes towards Hampshire, New Milton is around 17 miles away. South West homes range from terraced streets in the cities to stone cottages and bungalows in the countryside, and conservation areas are common in historic centres.
Will the council need to approve it?
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
How the project works
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions people ask about pitched roof extensions
How long does a pitched roof extension take to build in Swanage?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 6–12 weeks design and approvals.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Swanage, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Who do I contract with for a pitched roof extension in Swanage?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Can I have a vaulted ceiling?
Yes. A vaulted ceiling with roof windows is one of the main reasons to choose a pitched roof. It needs insulation between and under the rafters to meet the building regulations.
Is a pitched roof better than a flat roof?
Neither is better in all cases. Pitched roofs blend with traditional houses and shed water quickly; flat roofs give more headroom and suit modern designs and lanterns.
Book a free site visit in Swanage
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.