Sidmouth, Devon
Semi-detached rear extension in Sidmouth
For homes in Sidmouth, a semi-detached rear extension is often the simplest way to gain space without moving. Single or two-storey extensions for semi-detached houses, with side access and one party wall. We take it from survey to completion certificate.
Sidmouth and its postcode districts EX10 are part of our Devon coverage. Semi-detached houses are common across Devon, 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 Sidmouth?
A semi-detached rear extension in Sidmouth 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 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a semi-detached rear extension in Sidmouth?
Here is how the rules in England apply to a semi-detached rear extension in Sidmouth.
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 Sidmouth like to extend?
Stone-built and rendered houses are common around Sidmouth, 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 Sidmouth 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.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Semi-detached rear extensions near Sidmouth
From Sidmouth, the nearest places we also cover are Honiton (7.8 miles) and Exmouth (8.8 miles).
- Semi-detached rear extension in Honiton
- Semi-detached rear extension in Exmouth
- Semi-detached rear extension in Heavitree
- Semi-detached rear extension in Dawlish
- Semi-detached rear extension in Exeter
Other work in Sidmouth:
FAQ
Semi-detached rear extension questions in Sidmouth
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.
Is the site visit in Sidmouth free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
How long does a semi extension take?
10 to 16 weeks on site for a single-storey extension.
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 long does a rear extension take to build in Sidmouth?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
How much does a semi-detached rear extension cost in Sidmouth?
As a guide, £1,980–£3,220 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £23,500–£38,500 at that rate. Your written price follows the survey.