Chalfont St Peter pitched roof extensions, designed and built
If you live in Chalfont St Peter and want more space without moving, a pitched roof extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide price in Chalfont St PeterFrom £24,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsSL9

Working in Chalfont St Peter
Across SL9, we can visit, measure and advise. Nearby, we also take on projects in Gerrards Cross (2 miles), Amersham (5 miles), Chesham (7 miles), High Wycombe (8 miles).
For homes towards Hertfordshire, Rickmansworth is around 4 miles away. The South East has a broad mix of 1930s semis, post-war estates, newer developments and period cottages, and many houses have enough garden for a generous rear extension.
Planning rules that apply in Chalfont St Peter
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.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
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.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
Pitched roof extension prices in Chalfont St Peter
These guide figures apply our South East England adjustment (×1.12) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Chalfont St Peter: £2,070 to £3,920 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £24,500 – £29,000 | £28,500 – £37,000 | £36,500 – £47,500 |
| 4 m × 5 m 20 m² | £41,000 – £48,500 | £48,000 – £62,000 | £61,500 – £78,500 |
| 5 m × 6 m 30 m² | £62,000 – £72,500 | £72,000 – £92,500 | £92,000 – £118,000 |
Try the guide-price tool to see a range for your own size and finish.
What we take care of
- Roof windows positioned for light and ventilation
- Insulation to current building regulations
- Roof design matched to the existing pitch and tiles
- Lead or proprietary flashings to the main wall
- Vaulted ceilings or flat ceilings with storage above
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.
From first visit to completion
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
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
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Your questions about a pitched roof extension in Chalfont St Peter
How long does a pitched roof extension take to build in Chalfont St Peter?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 6–12 weeks design and approvals.
Will my neighbours in Chalfont St Peter be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Do you cover all of Chalfont St Peter?
Yes. We cover Chalfont St Peter and the surrounding parts of Buckinghamshire. Site visits are free and there is no obligation.
How much does a pitched roof extension cost?
Our guide range is about £2,070 to £3,920 per m² including VAT, a little more than a flat roof because of the roof structure and tiles.
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.
Book a free site visit in Chalfont St Peter
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.