Single-storey rear extensions in Melksham
Melksham homeowners can use us for the whole single-storey extension project: survey, design, planning or permitted development checks, building regulations and the build itself.
- Guide price in MelkshamFrom £21,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsSN12

Do I need planning permission in Melksham?
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
Covering Melksham
Postcode districts we cover around Melksham include SN12. Nearby, we also take on projects in Trowbridge (5 miles), Chippenham (6 miles), Devizes (7 miles), Calne (8 miles).
For homes towards Somerset, Bath is around 10 miles away. 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.
Who a single-storey extension suits
- Semi-detached and detached houses with a usable rear garden
- Terraced houses that want a deeper kitchen across the full width
- Homeowners who want open-plan living onto the garden
Depth is the big decision. Every extra metre adds floor area but also takes garden and can push you out of permitted development. We draw the room at two or three depths so you can see the trade-off in space, light and cost before anything is fixed.
Guide prices for Melksham
Prices below are for Melksham, using the South West England factor of ×1.02. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Melksham: £1,780 to £3,470 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £21,000 – £25,500 | £25,000 – £32,000 | £31,500 – £42,000 |
| 4 m × 5 m 20 m² | £35,500 – £42,000 | £41,500 – £53,500 | £53,000 – £69,500 |
| 5 m × 6 m 30 m² | £53,500 – £63,000 | £62,500 – £80,000 | £79,500 – £104,500 |
Try the guide-price tool to see a range for your own size and finish.
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
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Common questions in Melksham
Do I need building regulations approval in Melksham?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Melksham, 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 single-storey extension in Melksham?
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.
How deep can a single-storey rear extension be without planning permission?
In England, up to 3 m beyond the original rear wall on a semi-detached or terraced house and 4 m on a detached house, within height and boundary limits. Through the larger home extension prior approval scheme those depths rise to 6 m and 8 m. Wales, Scotland and Northern Ireland use their own rules, which we check for your address.
Will I need a steel beam?
Almost always. Opening up the rear wall to join the new room to the house needs a beam, usually steel, sized by a structural engineer. It is included in our quotes.
Book a free site visit in Melksham
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.