A single-storey extension is a new ground-floor room built onto your house, usually at the rear or side, with its own foundations, walls and roof, creating a bigger kitchen, living space or bedroom without moving home.
If you live in Llanelli and are weighing up a single-storey extension, the starting point is a visit to measure up and talk through what you want, which costs nothing. We cover homes across SA15, and a typical project of this kind in Wales lands somewhere in the £32,000–£69,000 bracket, including VAT. The exact figure depends on size, access and the finish you choose.
- Guide price
- £32,000–£69,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- SA15
- Planning rules
- Wales
- Local area
- Carmarthenshire
- Survey
- Free, with a written quote
How much does a single-storey extension cost in Llanelli?
The costs listed here are typical for a single-storey extension around Llanelli and include VAT. They reflect labour and material costs in Wales, about 8% below the national guide, giving a range of £32,000–£69,000. Exact pricing depends on your home, so we only fix it once a free site survey is done.
| Type of job | What it usually involves | Guide in Llanelli |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £20,000–£37,000 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £32,000–£69,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £64,000–£120,000 |
The main things that change the figure:
- Floor area, shape and number of corners
- Roof type, rooflights, lanterns and the amount of glazing
- Steelwork needed to open into the existing house
- Finishes, kitchen, flooring and heating specification
What do you get?
- Groundworks, foundations and below-ground drainage
- Cavity walls built and insulated to building regulations
- Flat or pitched roof, with rooflights or a lantern if specified
- Electrics and plumbing by qualified trades, with certificates
- Plastering, screed floor and internal doors
- Building control inspections and completion certificate
Building in Llanelli
Dyfed covers Carmarthenshire, Ceredigion and Pembrokeshire. Stone cottages and farmhouses under slate roofs are common, often rendered or colour-washed, as in Tenby's brightly painted terraces. Llanelli has Victorian industrial terraces, Aberystwyth and Carmarthen have Georgian and Victorian centres, and bungalows and newer estates surround most towns.
Stone homes often need lime render, repointing and roof slating repairs. Terraces suit loft conversions and extensions, and rural bungalows commonly take extensions, porches and driveways.
If your house in Llanelli fits one of these patterns, it helps us anticipate what a single-storey extension will involve, though we always confirm the details on site.
Permissions for a single-storey extension in Llanelli
England, Wales, Scotland and Northern Ireland each handle planning a little differently. Llanelli comes under Wales, covered below, and we raise any questions with the council before your quote is finalised.
In Wales, permitted development allows many single-storey rear extensions, with depth and height limits that depend on the type of house and how close the extension comes to your boundaries. Side extensions, listed buildings, conservation areas and flats usually need planning permission.
Building Regulations in Wales apply to extensions, from foundations to insulation and fire safety. The Party Wall etc. Act 1996 applies in Wales as it does in England.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
The four stages
Free site survey
We begin by looking at the job in person. During the free survey we discuss options, materials and budget for a single-storey extension, and photograph or measure anything the quote needs to reflect.
Your fixed price
You get the price in writing, itemised so you can see where the money goes. As long as the specification stays the same, that is the price you pay for a single-storey extension.
Booking the work
Preparation matters as much as the build. We agree access, parking and working hours with you, order materials in good time, and confirm any permissions so the job isn't held up once it starts.
Build and hand over
Our trades complete a single-storey extension while your point of contact keeps you updated. When everything is finished, we clear the site, take away waste and go through the result with you before handover.
Working with SK Home Improvements
Frequently asked questions
How long does a single-storey extension take to build?
A single-storey extension usually takes 10–16 weeks on site, from digging foundations to final plastering. Bad weather, deep foundations or a complex roof can add time. Before work starts, allow several weeks for drawings, structural calculations and building control approval, and longer if planning permission is needed. We give you a stage-by-stage programme with your quote so you know what happens each week.
How much will a single-storey extension cost in Llanelli?
As a guide, expect to pay £32,000–£69,000 including VAT for a single-storey extension in Llanelli. That range is adjusted for Wales, which runs about 8% below the national guide. Where your project lands depends on size, materials, access and the condition of what is already there. We confirm a fixed price in writing after a free survey of your home.
Is a flat roof or a pitched roof better on an extension?
A flat roof is quicker to build and usually costs less, gives a clean modern look and works well with a roof lantern. A pitched roof matches the main house, sheds water faster and allows a vaulted ceiling, but it costs more and its height can affect neighbours. Modern flat roofs in EPDM rubber or GRP last well when properly detailed. Planning rules on height can also decide the choice.
Do you cover Gorseinon, Swansea and Ammanford?
Yes. As well as Llanelli, we cover Gorseinon, Swansea and Ammanford and the rest of Dyfed. Our coverage is UK-wide, so the process is the same wherever you are: a free site survey, a quote in writing that fixes the price for the agreed scope, and one point of contact while the work is planned and carried out.
What does a typical extension build look like week by week?
A typical single-storey extension follows the same order: clearing the site and digging foundations, building walls up to roof level, then fitting the roof and windows to make it weathertight. Electrics, plumbing, insulation and plastering follow. The last stage is opening into the house, laying the screed and fitting doors and finishes. Building control inspects at key stages, and we book those visits for you.
Nearby towns
From SA15 to the edges of Llanelli and on into Gorseinon, Swansea and Ammanford, we can arrange a site visit and a written quote for your project, planned around dates that work for you.