Pitched roof extensions in Thornbury: design, approvals and build
If you live in Thornbury 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 ThornburyFrom £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 districtsBS35
Planning and approvals in Thornbury
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.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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).
Local to Thornbury
Across BS35, we can visit, measure and advise. The same team covers Yate (7 miles), Mangotsfield (8 miles), Kingswood (10 miles), Dursley (10 miles), all within easy reach.
In the South West, local stone, render and brick vary from town to town, so matching materials is a big part of designing an extension that looks right.
Is a pitched roof extension right for your house?
- Homeowners who prefer a vaulted ceiling
- Traditional, period and rural houses
- Conservation-sensitive streets
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.
Guide prices for Thornbury
Labour and material costs vary across the UK, so for Thornbury we use our South West England factor (×1.02). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Thornbury: £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.
Our process, step by step
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
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Your questions about a pitched roof extension in Thornbury
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Thornbury, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How long does a pitched roof extension take to build in Thornbury?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 6–12 weeks design and approvals.
Do I need building regulations approval in Thornbury?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
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.
How much does a pitched roof extension cost?
Our guide range is about £1,890 to £3,570 per m² including VAT, a little more than a flat roof because of the roof structure and tiles.
Book a free site visit in Thornbury
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.