Rhondda, South Wales Valleys
Semi-detached rear extension in Rhondda
For homes in Rhondda, 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.
Rhondda is covered from our South Wales Valleys round, including CF40, CF41 and CF43. 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 Rhondda?
A semi-detached rear extension in Rhondda 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 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a semi-detached rear extension in Rhondda?
Planning for a semi-detached rear extension in Rhondda follows the Welsh householder rules.
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.
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 Rhondda like to extend?
Rhondda is largely terraced streets on sloping ground, where back gardens step up or down from the house. Excavation, retaining walls and drainage are priced at the survey.
How a semi-detached rear extension in Rhondda 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 or householder planning application, then Building Regulations drawings to the Welsh Approved Documents and structural calculations, plus party wall notices where they apply.
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 Rhondda
From Rhondda, the nearest places we also cover are Tonypandy (2.6 miles) and Mountain Ash (3.4 miles).
- Semi-detached rear extension in Tonypandy
- Semi-detached rear extension in Mountain Ash
- Semi-detached rear extension in Aberdare
- Semi-detached rear extension in Pontypridd
- Semi-detached rear extension in Treharris
Other work in Rhondda:
FAQ
Semi-detached rear extension questions in Rhondda
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 you match the brick or stone on my Rhondda house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
What if my neighbour has already extended?
That can make a matching depth easier to justify. We measure theirs at the survey.
Do you handle building control in Rhondda?
Yes. We apply to the council or a registered approver under the Welsh regulations and hand over the completion certificate.
What postcode areas do you cover around Rhondda?
Including CF40, CF41 and CF43, and the surrounding South Wales Valleys area.
Is the site visit in Rhondda free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.