Swansea Bay
Permitted development rear extensions in Swansea Bay
Designing to the no-application limits, with a lawful development certificate as proof. We design and build rear extensions across Swansea Bay, from Swansea and Neath to Briton Ferry, covering single-storey kitchen extensions, two-storey additions, side returns and wraparounds.

Swansea Bay has Victorian terraces near the centre and semis further out. Welsh permitted development allows up to 4 metres at the rear for many houses.
How much does a permitted development rear extension cost in Swansea Bay?
A permitted development rear extension in Swansea Bay 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 in Swansea Bay?
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 Swansea Bay do we work?
FAQ
Questions people ask
Is permitted development the same as planning permission?
No; it is a national grant of permission for work within set limits, so no application is needed.
Do I still need Building Regulations?
Yes, always.
Can my neighbours object?
Not to permitted development itself, though they can ask the council to check it complies. Prior approval does involve neighbour consultation.
Do you cover all of Swansea Bay?
We cover 6 towns and districts in Swansea Bay, including Swansea, Neath and Briton Ferry.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.