Brynmawr, South Wales Valleys
Semi-detached rear extension in Brynmawr
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 Brynmawr and the surrounding area, with one contract from the first survey to building control sign-off.
We cover Brynmawr (NP22 and NP23) as part of our South Wales Valleys work. 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 Brynmawr?
In Brynmawr, our guide for a semi-detached rear extension is £1,770–£2,880 per square metre including VAT for a standard specification. 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 Brynmawr?
Here is how the rules in Wales apply to a semi-detached rear extension in Brynmawr.
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 Brynmawr like to extend?
Stone terraces along the valley floors and post-war semis higher up are typical of Brynmawr. Sloping sites are common, so floor levels and retaining walls are designed at the start.
How a semi-detached rear extension in Brynmawr 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.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Semi-detached rear extensions near Brynmawr
Neighbouring places we cover include Ebbw Vale (1.9 miles) and Tredegar (3.3 miles).
- Semi-detached rear extension in Ebbw Vale
- Semi-detached rear extension in Tredegar
- Semi-detached rear extension in Abertillery
- Semi-detached rear extension in Abergavenny
- Semi-detached rear extension in Bargoed
Other work in Brynmawr:
FAQ
Semi-detached rear extension questions in Brynmawr
How much does a semi-detached rear extension cost in Brynmawr?
As a guide, £1,770–£2,880 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £21,000–£34,500 at that rate. Your written price follows the survey.
Do you handle building control in Brynmawr?
Yes. We apply to the council or a registered approver under the Welsh regulations and hand over the completion certificate.
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.
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.
Is the site visit in Brynmawr free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.