Clacton-on-Sea, Essex
Semi-detached rear extension in Clacton-on-Sea
Single or two-storey extensions for semi-detached houses, with side access and one party wall. We design, get the approvals for and build rear extensions for semi-detached houses in Clacton-on-Sea and the surrounding area, with one contract from the first survey to building control sign-off.
Clacton-on-Sea and its postcode districts CO15 are part of our Essex coverage. Semi-detached houses are common across Essex, 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 Clacton-on-Sea?
A semi-detached rear extension in Clacton-on-Sea is priced at £2,010–£3,290 per square metre including VAT as a guide, before kitchen fit-out and fees. East of England prices run slightly above our West Midlands baseline; clay soils near trees are the main foundation variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £24,000–£39,500 |
| 4 m wide × 5 m deep (20 m²) | £40,500–£65,500 |
| 4 m wide × 6 m deep (24 m²) | £48,500–£79,000 |
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 Clacton-on-Sea?
The planning route for a semi-detached rear extension in Clacton-on-Sea is set by England's householder rules and your council.
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.
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. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.
What are homes in Clacton-on-Sea like to extend?
Clacton-on-Sea mixes Victorian terraces with 1930s semis, so both side returns and full-width kitchen extensions suit houses here.
How a semi-detached rear extension in Clacton-on-Sea 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.
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 Clacton-on-Sea
We also build rear extensions for semi-detached houses in nearby Frinton-on-Sea (4.7 miles) and Walton-on-the-Naze (6.2 miles).
- Semi-detached rear extension in Frinton-on-Sea
- Semi-detached rear extension in Walton-on-the-Naze
- Semi-detached rear extension in Harwich
- Semi-detached rear extension in Colchester
- Semi-detached rear extension in Felixstowe
Other work in Clacton-on-Sea:
FAQ
Semi-detached rear extension questions in Clacton-on-Sea
Is the site visit in Clacton-on-Sea free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
How long does a rear extension take to build in Clacton-on-Sea?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
What if my neighbour has already extended?
That can make a matching depth easier to justify. We measure theirs at the survey.
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.
What postcode areas do you cover around Clacton-on-Sea?
Including CO15, and the surrounding Essex area.