South Wales Valleys
Rear extensions for terraced houses in the South Wales Valleys
Rear and side return extensions for terraces, with access through the house and two neighbours. 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.

On a Rhondda terrace both neighbours usually need party wall notices or agreement, so we talk to them early. 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 terraced house rear extension cost in the South Wales Valleys?
A terraced house rear extension in the South Wales Valleys is priced at £1,910–£3,070 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 × 4.5 m deep (13.5 m²) | £25,500–£41,500 |
| 3 m wide × 6 m deep (18 m²) | £34,500–£55,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
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.
In Wales, as in England, the Party Wall etc. Act 1996 requires notice to neighbours before work to a shared wall or excavation near their foundations.
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 you build without side access?
Yes. Materials come through the house in protected runs or over the roof by crane on tight sites.
Do both neighbours need party wall notices?
Usually yes in England and Wales, because the extension often sits on or near both boundaries.
Will my terrace be in a conservation area?
Many Victorian terraces are. Your council's map shows it; we check at the survey.
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.