Side return extensions across Carmarthen
Planning a side return extension in Carmarthen? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in CarmarthenFrom £16,500 inc VAT
- PlanningCan be permitted development; party wall notice usual
- Build time10–14 weeks on site
- Postcode districtsSA31

Who a side return extension suits
- Victorian and Edwardian terraces with a rear outrigger
- Narrow galley kitchens
- Homes where the garden is too small to lose much depth
Working in Carmarthen
Postcode districts we cover around Carmarthen include SA31. The same team covers Llanelli (13 miles), Ammanford (14 miles), Haverfordwest (29 miles), Pembroke Dock (29 miles), all within easy reach.
Just over the West Glamorgan border, Gorseinon is about 17 miles away. In Wales, terraced houses with rear offshoots are common in the towns, while detached houses and bungalows dominate in rural areas.
Will the council need to approve it?
In Wales a single-storey side return can fall within permitted development if it stays within the 4 m height limit and the width rules for side extensions. Conservation areas and listed buildings need consent, and the Party Wall Act applies to work on or near a shared wall.
Homes in conservation areas, national parks, National Landscapes (AONBs) and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
The Party Wall etc. Act 1996 applies in Wales as in England: notice must be served before work to a shared wall, building on the boundary, or excavating close to a neighbour's foundations.
Building regulations approval is separate from planning. Wales has its own building regulations and approved documents; the council or a registered building control approver checks the plans, inspects the work and issues a completion certificate.
Applications are decided by the local planning authority (your county or county borough council, or the national park authority).
Side return extension prices in Carmarthen
These guide figures apply our Wales adjustment (×0.93) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Carmarthen: £1,950 to £3,530 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 1.8 m × 4.5 m 8 m² | £16,500 – £20,000 | £17,500 – £22,500 | £22,000 – £28,500 |
| 2 m × 5.5 m 11 m² | £21,000 – £26,000 | £24,500 – £31,000 | £30,500 – £39,000 |
| 2.2 m × 7 m 15 m² | £29,000 – £35,000 | £33,000 – £42,000 | £41,500 – £53,500 |
For a figure based on your own dimensions, use our guide-price tool.
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Side return extension questions answered
How long does a side return extension take to build in Carmarthen?
On site, typically 10 to 14 weeks once approvals are in place. Before that, allow 6–12 weeks design and approvals.
Do you cover all of Carmarthen?
Yes. We cover Carmarthen and the surrounding parts of Dyfed. Site visits are free and there is no obligation.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Carmarthen, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Will the kitchen be darker?
Not if the roof is designed well. A glazed roof or a line of rooflights along the boundary usually makes the room brighter than before.
Can I combine a side return with a rear extension?
Yes. That combination is a wraparound extension, which adds the most space to a terraced house.
Book a free site visit in Carmarthen
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.