Bargoed, South Wales Valleys
Semi-detached rear extension in Bargoed
Semi-detached rear extension in Bargoed: single or two-storey extensions for semi-detached houses, with side access and one party wall. We measure the house, show you what the rules allow, price it in writing and build it.
Bargoed is covered from our South Wales Valleys round, including CF81. Where a Bargoed semi already has a small lean-to at the back, we usually replace it rather than extend it.
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 Bargoed?
In Bargoed, 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 |
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 Bargoed?
Whether your semi-detached rear extension in Bargoed needs a planning application depends on its size, your house and any local restrictions.
The Welsh Government's householder rules let many homes add a single-storey rear extension up to 4 metres deep and 4 metres high without a planning application. Deeper projects go through a householder application, because Wales has no prior approval route.
In Wales a rear extension of more than one storey can be permitted development if the ground floor projects no more than 4 metres and the upper floor no more than 3 metres, with at least 10.5 metres to the rear boundary. It is not permitted development in conservation areas, National Parks or National Landscapes, so many double-storey schemes need a householder application.
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 Bargoed like to extend?
Stone terraces along the valley floors and post-war semis higher up are typical of Bargoed. Sloping sites are common, so floor levels and retaining walls are designed at the start.
How a semi-detached rear extension in Bargoed 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.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
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 Bargoed
Close by, we work in Blackwood, about 1.5 miles away, and Gelligaer, about 1.6 miles away.
- Semi-detached rear extension in Blackwood
- Semi-detached rear extension in Gelligaer
- Semi-detached rear extension in Nelson
- Semi-detached rear extension in Treharris
- Semi-detached rear extension in Abercarn
Other work in Bargoed:
FAQ
Semi-detached rear extension questions in Bargoed
Do I need a party wall agreement?
In Wales, usually yes if the extension is on or near a shared boundary or close to a neighbour's foundations. We serve the notices.
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 match pebbledash or render?
Yes. Many semis are refinished with new render across the whole back elevation so old and new match.
What postcode areas do you cover around Bargoed?
Including CF81, and the surrounding South Wales Valleys area.
How long does a rear extension take to build in Bargoed?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Is the site visit in Bargoed free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.