West Wales
Glazed and glass-box rear extensions in West Wales
Full-height glass, slim frames and big rooflights for the most open rear room. Across West Wales we handle the whole rear extension: survey, drawings, the planning route, building control and the build. Towns we cover here include Llanelli, Aberystwyth and Carmarthen.

Glass-led rear extensions in Llanelli are planned around which way the garden faces, because that decides the glass specification. Older terraces near the centre and post-war semis further out are typical of West Wales. Sloping sites are common in Wales, so floor levels and retaining walls are designed at the start.
How much does a glazed rear extension cost in West Wales?
A glazed rear extension in West Wales is priced at £2,600–£4,460 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) | £31,000–£53,500 |
| 4 m wide × 6 m deep (24 m²) | £62,500–£107,000 |
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 West Wales?
The Welsh Government's householder rules let many homes add a single-storey rear extension up to 4 metres deep and 4 metres high without a planning application. Deeper projects go through a householder application, because Wales has no prior approval route.
Wales has its own Approved Document L, with targets for walls, roofs, floors and glazing similar to but not identical with England's. Heavily glazed designs are checked with a calculation.
Conservation areas, National Parks and National Landscapes restrict permitted development in Wales, and listed buildings need listed building consent.
Where in West Wales do we work?
FAQ
Questions people ask
Will a glass extension be too hot?
Not if it is designed for its orientation, with solar-control glass, shading and ventilation.
Sliding or bifold doors?
Sliders give bigger panes and slimmer sightlines; bifolds open the whole width. Our guide compares them.
Can I have a level threshold?
Yes, with a drainage channel outside the doors and the slab set to the patio level.
Do you cover all of West Wales?
We cover 6 towns and districts in West Wales, including Llanelli, Aberystwyth and Carmarthen.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.