Midsomer Norton, Somerset
Semi-detached rear extension in Midsomer Norton
Single or two-storey extensions for semi-detached houses, with side access and one party wall. If you live in Midsomer Norton and want to know what a semi-detached rear extension would cost and whether it needs planning, start with the online guide price or a free site visit.
Midsomer Norton is covered from our Somerset round, including BA3. Semi-detached houses are common across Somerset, and their side access makes rear extensions quicker to build.
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 semi-detached rear extension cost in Midsomer Norton?
For Midsomer Norton we work from the South West England rate: £1,980–£3,220 per square metre of new floor, including VAT, standard specification. 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 semi-detached rear extension in Midsomer Norton?
Here is how the rules in England apply to a semi-detached rear extension in Midsomer Norton.
Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it is within 2 metres of a boundary.
A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. Before any drawing we look up the property's history with the council, because earlier extensions and removed rights change the answer.
What are homes in Midsomer Norton like to extend?
Stone-built and rendered houses are common around Midsomer Norton, so matching the walling is a design decision in its own right: natural stone, reconstituted stone or a render finish across old and new.
How a semi-detached rear extension in Midsomer Norton comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Semi-detached rear extensions near Midsomer Norton
Close by, we work in Shepton Mallet, about 7.1 miles away, and Frome, about 8.1 miles away.
- Semi-detached rear extension in Shepton Mallet
- Semi-detached rear extension in Frome
- Semi-detached rear extension in Bath
- Semi-detached rear extension in Wells
- Semi-detached rear extension in Keynsham
Other work in Midsomer Norton:
FAQ
Semi-detached rear extension questions in Midsomer Norton
How long does a rear extension take to build in Midsomer Norton?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
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.
Can I match pebbledash or render?
Yes. Many semis are refinished with new render across the whole back elevation so old and new match.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
What postcode areas do you cover around Midsomer Norton?
Including BA3, and the surrounding Somerset area.
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.