Cwmbran, South Wales Valleys
Semi-detached rear extension in Cwmbran
Thinking about a semi-detached rear extension in Cwmbran? Single or two-storey extensions for semi-detached houses, with side access and one party wall. Our team handles the drawings, the planning route and the build, and your contract is with one company throughout.
Cwmbran sits in the South Wales Valleys, with postcode districts including NP44. Semi-detached houses are common across the South Wales Valleys, 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 Cwmbran?
A semi-detached rear extension in Cwmbran is priced at £1,770–£2,880 per square metre including VAT as a guide, before kitchen fit-out and fees. Prices in Wales sit below our West Midlands baseline; sloping sites are the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £21,000–£34,500 |
| 4 m wide × 5 m deep (20 m²) | £35,500–£57,500 |
| 4 m wide × 6 m deep (24 m²) | £42,500–£69,000 |
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 Cwmbran?
Here is how the rules in Wales apply to a semi-detached rear extension in Cwmbran.
In Wales a single-storey rear extension can often be permitted development if it projects no more than 4 metres beyond the rear wall and is no more than 4 metres high. Wales has no prior approval route for deeper extensions, so anything bigger needs a householder planning application.
Welsh rules allow a two-storey rear extension without an application only where the ground floor is no deeper than 4 metres, the upper floor no deeper than 3 metres and at least 10.5 metres remains to the rear boundary. Most homeowners still apply for householder planning permission.
Conservation areas, National Parks and National Landscapes restrict permitted development in Wales, and listed buildings 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 Cwmbran like to extend?
Stone terraces along the valley floors and post-war semis higher up are typical of Cwmbran. Sloping sites are common, so floor levels and retaining walls are designed at the start.
How a semi-detached rear extension in Cwmbran 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.
Paperwork handled
Planning or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
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 Cwmbran
Close by, we work in Pontypool, about 3.4 miles away, and Caerleon, about 4.3 miles away.
- Semi-detached rear extension in Pontypool
- Semi-detached rear extension in Caerleon
- Semi-detached rear extension in Risca
- Semi-detached rear extension in Newport
- Semi-detached rear extension in Abercarn
Other work in Cwmbran:
FAQ
Semi-detached rear extension questions in Cwmbran
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
How long does a rear extension take to build in Cwmbran?
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 match pebbledash or render?
Yes. Many semis are refinished with new render across the whole back elevation so old and new match.
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.
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.
Can you match the brick or stone on my Cwmbran house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.