Westbury, Wiltshire
Single-storey rear extension in Westbury
Ground-floor space across the back of the house, usually for a kitchen, dining or family room. We design, get the approvals for and build single-storey rear extensions in Westbury and the surrounding area, with one contract from the first survey to building control sign-off.
Westbury is covered from our Wiltshire round, including BA13. A depth of 3 to 4 metres keeps many single-storey rear extensions in Westbury within permitted development, subject to the house's planning history.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a single-storey rear extension cost in Westbury?
A single-storey rear extension in Westbury is priced at £1,980–£3,220 per square metre including VAT as a guide, before kitchen fit-out and fees. South West prices run slightly above our West Midlands baseline; natural stone to match the house is the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £23,500–£38,500 |
| 4 m wide × 5 m deep (20 m²) | £39,500–£64,500 |
| 4 m wide × 6 m deep (24 m²) | £47,500–£77,500 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission for a single-storey rear extension in Westbury?
Here is how the rules in England apply to a single-storey rear extension in Westbury.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
If 3 or 4 metres is not enough, England's prior approval route allows 6 metres on a terraced or semi-detached house and 8 metres on a detached house for a single-storey rear extension. Neighbours are consulted, the council decides within 42 days, and the fee is £249, rising to £310 from 8 December 2026.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Westbury like to extend?
Westbury has Victorian terraces nearer the centre and post-war semis on the edges. Sloping gardens are frequent, which affects floor levels and steps down to the patio.
How a single-storey rear extension in Westbury comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Single-storey rear extensions near Westbury
From Westbury, the nearest places we also cover are Warminster (3.9 miles) and Trowbridge (4.2 miles).
- Single-storey rear extension in Warminster
- Single-storey rear extension in Trowbridge
- Single-storey rear extension in Frome
- Single-storey rear extension in Melksham
- Single-storey rear extension in Devizes
Other work in Westbury:
FAQ
Single-storey rear extension questions in Westbury
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
How deep can a single-storey rear extension be without planning?
In England, 3 metres on an attached house and 4 metres on a detached house under permitted development, or up to 6 and 8 metres with prior approval. Wales allows 4 metres; Scotland and Northern Ireland have their own limits.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
Can you match the brick or stone on my Westbury house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.