Extending your home in Melksham
Planning an extension in Melksham? Compare extension types, see guide prices adjusted for Melksham and book a free site visit.
- Postcode districtsSN12
- Price regionSouth West England (×1.02)
- Planning rulesEngland
- Site visitFree, no obligation

Melksham extension prices at a glance
Every figure below is a guide for Melksham, adjusted for South West England build costs (×1.02) and including VAT. Design and council fees are shown separately on each page.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Extensions over a garage | 12 m² | £25,500 – £33,500 |
| Double-storey extensions | 32 m² | £58,500 – £77,000 |
| Conservatory replacement extensions | 14 m² | £30,500 – £39,500 |
| Side return extensions | 11 m² | £26,500 – £34,000 |
| Orangery extensions | 16 m² | £45,500 – £57,500 |
| Kitchen extensions | 20 m² | £42,500 – £54,500 |
| Single-storey rear extensions | 20 m² | £41,500 – £53,500 |
Planning rules 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 England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
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).
Melksham and surrounding towns
Postcode districts we cover around Melksham include SN12. Neighbouring towns we cover include Trowbridge (5 miles), Chippenham (6 miles), Devizes (7 miles), Calne (8 miles), Warminster (14 miles). Bath, in Somerset, is roughly 10 miles from Melksham and also on our list.
What works best for Melksham houses?
South West homes range from terraced streets in the cities to stone cottages and bungalows in the countryside, and conservation areas are common in historic centres.
The types we would usually look at first for a home in Melksham are single-storey rear extensions, pitched roof extensions and orangery extensions, depending on the garden and how the house is laid out.
Choose an extension type
- Side return extensions · from £18,000
- Pitched roof extensions · from £22,500
- Annexe extensions · from £56,000
- Flat roof extensions · from £21,000
- Conservatory replacement extensions · from £20,000
- Porch extensions · from £4,050
- Extensions over a garage · from £24,000
- Utility and boot room extensions · from £14,000
- Building regulations for extensions · from £900
- Timber frame extensions · from £21,000
- Wraparound extensions · from £36,500
- Double-storey extensions · from £38,500
- Extension plans and drawings · from £1,200
- Single-storey rear extensions · from £21,000
- Planning permission for extensions · from £350
- Orangery extensions · from £30,500
- Side extensions · from £22,000
- Bedroom extensions · from £26,500
- Home office extensions · from £16,000
- Bungalow extensions · from £26,500
- Kitchen extensions · from £27,500
- Glass box extensions · from £30,500
Free site visit
We visit your Melksham home, measure up, talk through what you want and check the planning position.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions about extensions in Melksham
How much does an extension cost in Melksham?
Using our South West England factor (×1.02), a standard-spec single-storey extension of 20 m² is a guide £41,500 to £53,500 including VAT, and a 32 m² two-storey extension £58,500 to £77,000. Your written price follows the survey.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for Melksham, and the guide-price tool gives a range for your own size and finish in about a minute.
Do I need planning permission for an extension in Melksham?
Not always. It depends on the size, position and your property's history. Many single-storey rear extensions in England are permitted development or can use prior approval.
How long does an extension take in Melksham?
Usually 2 to 4 months of design and approvals, then 10 to 16 weeks on site for a single-storey extension or 16 to 24 weeks for two storeys.
Will my neighbours need to be told?
If you apply for planning or prior approval the council notifies them, and in England party wall notices may be needed for work near a shared boundary.
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.