Conservatory replacement extensions for homes in Thornbury
From the first sketch to final sign-off, we plan and build conservatory replacements in Thornbury and the surrounding Gloucestershire area.
- Guide price in ThornburyFrom £20,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–14 weeks on site
- Postcode districtsBS35
Planning rules that apply 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.
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 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).
How much does a conservatory replacement cost in 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 × 3.3 m 10 m² | £20,000 – £24,500 | £21,500 – £28,500 | £28,000 – £36,000 |
| 3.5 m × 4 m 14 m² | £26,000 – £31,500 | £30,500 – £39,500 | £39,000 – £50,000 |
| 4 m × 5 m 20 m² | £37,500 – £45,000 | £43,500 – £56,500 | £56,000 – £71,500 |
Includes removal of the old conservatory. Reusing existing foundations is only possible after investigation.
Try the guide-price tool to see a range for your own size and finish.
Covering 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.
Portishead, in Somerset, is roughly 12 miles from Thornbury and also on our list. 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.
What we take care of
- New or upgraded foundations
- Removal and disposal of the old conservatory
- Glazing and doors to suit the new room
- Insulated walls and roof to current regulations
- Trial holes to check the existing foundations
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
We visit your Thornbury home, measure up, talk through what you want and check the planning position.
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
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Your questions about a conservatory replacement in Thornbury
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.
Will my neighbours in Thornbury 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 Thornbury?
Yes. We cover Thornbury and the surrounding parts of Gloucestershire. Site visits are free and there is no obligation.
Does replacing a conservatory need planning permission?
A solid replacement is treated as a new extension, so it must meet the permitted development limits or get planning permission, and it always needs building regulations approval.
Is it worth replacing a conservatory with an extension?
If the conservatory is unusable for much of the year, usually yes. A solid extension gives a heated room that counts as proper living space. Our guide range is about £1,890 to £3,570 per m² including VAT, including removal.
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.