Mid Wales
Rear extensions for detached houses in Mid Wales
Wider, deeper rear extensions with room for vaulted roofs and big glazing. Rear extensions in Mid Wales: we cover 4 towns including Newtown, Brecon and Welshpool, with design, approvals and the build under one contract.

Older terraces near the centre and post-war semis further out are typical of Mid Wales. Sloping sites are common in Wales, so floor levels and retaining walls are designed at the start.
How much does a detached house rear extension cost in Mid Wales?
For Mid Wales we work from the Wales rate: £1,810–£2,980 per square metre of new floor, including VAT, standard specification. 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 Mid Wales?
Welsh permitted development allows a single-storey rear extension of up to 4 metres in depth and 4 metres in height, subject to boundary and garden-coverage limits. There is no larger-extension prior approval scheme in Wales.
In Wales a rear extension of more than one storey can be permitted development if the ground floor projects no more than 4 metres and the upper floor no more than 3 metres, with at least 10.5 metres to the rear boundary. It is not permitted development in conservation areas, National Parks or National Landscapes, so many double-storey schemes need a householder application.
Conservation areas, National Parks and National Landscapes restrict permitted development in Wales, and listed buildings need listed building consent.
Where in Mid Wales 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 Mid Wales?
We cover 4 towns and districts in Mid Wales, including Newtown, Brecon and Welshpool.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.