Cardiff and the Vale
Two-storey rear extensions in Cardiff and the Vale
A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. We design and build rear extensions across Cardiff and the Vale, from Cardiff and Barry to Penarth, covering single-storey kitchen extensions, two-storey additions, side returns and wraparounds.
In Cardiff and the Vale we check the neighbours' rear windows first, because the upper floor is where most two-storey schemes win or lose planning. Older terraces near the centre and post-war semis further out are typical of Cardiff and the Vale. Sloping sites are common in Wales, so floor levels and retaining walls are designed at the start.
How much does a two-storey rear extension cost in Cardiff and the Vale?
Guide prices for a two-storey rear extension in Cardiff and the Vale start from our Wales rate of £1,670–£2,510 per square metre, including VAT. Prices in Wales sit below our West Midlands baseline; sloping sites are the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m × 5 m footprint, two floors (30 m²) | £50,000–£75,500 |
| 4 m × 6 m footprint, two floors (48 m²) | £80,500–£120,500 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission in Cardiff and the Vale?
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 Cardiff and the Vale do we work?
FAQ
Questions people ask
Does a two-storey rear extension need planning permission?
Almost always. England and Northern Ireland allow 3 metres without an application only if at least 7 metres remains to the rear boundary; Wales and Scotland are similar or stricter.
Is two-storey cheaper per square metre than single-storey?
Usually yes, because the foundations and roof are shared across twice the floor area. The total cost is higher.
Can I add an en-suite upstairs?
Yes. We plan the soil pipe route early so the bathroom sits where drainage works without boxing through the room below.
Do you cover all of Cardiff and the Vale?
We cover 6 towns and districts in Cardiff and the Vale, including Cardiff, Barry and Penarth.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.