South Wales Valleys
Rear extensions for detached houses in the South Wales Valleys
Wider, deeper rear extensions with room for vaulted roofs and big glazing. We design and build rear extensions across the South Wales Valleys, from Rhondda and Tonypandy to Bridgend, covering single-storey kitchen extensions, two-storey additions, side returns and wraparounds.
South Wales Valleys 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 much does a detached house rear extension cost in the South Wales Valleys?
A detached house rear extension in the South Wales Valleys is priced at £1,810–£2,980 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 |
|---|---|
| 4 m wide × 6 m deep (24 m²) | £43,500–£71,500 |
| 5 m wide × 8 m deep (40 m²) | £72,500–£119,000 |
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 in the South Wales Valleys?
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.
Where in the South Wales Valleys do we work?
FAQ
Questions people ask
Can I have a vaulted ceiling?
Yes, with a pitched roof and exposed or boxed rafters, subject to the height limits.
Is an oak frame worth it?
It is a premium finish with a long life; it costs more than blockwork with a plain roof.
Do I need party wall notices?
Only if the extension is close enough to a neighbour's building for the excavation rules to apply.
Do you cover all of the South Wales Valleys?
We cover 27 towns and districts in the South Wales Valleys, including Rhondda, Tonypandy and Bridgend.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.