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.
We arrange a single-storey extension for homeowners in Llantwit Major and the wider South Glamorgan. The job is planned, priced and managed by us and carried out by tradespeople engaged under our contract, so there is one agreement and one contact. On a typical home the work takes 10–16 weeks on site, and guide pricing in Wales is £32,000–£69,000, VAT included.
- Guide price
- £32,000–£69,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- CF61
- Planning rules
- Wales
- Local area
- The Vale of Glamorgan
- Survey
- Free, with a written quote
Single-storey extensions prices in Llantwit Major
Below is a breakdown of typical costs for a single-storey extension in Llantwit Major. Because rates in Wales are about 8% below the national guide, the overall guide comes to £32,000–£69,000, including VAT. Size, materials and access move the figure, and a free-of-charge survey settles it.
| Type of job | What it usually involves | Guide in Llantwit Major |
|---|---|---|
| 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 |
Expect these to shape the final quote:
- Roof type, rooflights, lanterns and the amount of glazing
- Ground conditions, foundation depth and drains to divert
- Steelwork needed to open into the existing house
- Finishes, kitchen, flooring and heating specification
Scope of the work
- Groundworks, foundations and below-ground drainage
- Cavity walls built and insulated to building regulations
- Steel beams to open into the existing house
- Electrics and plumbing by qualified trades, with certificates
- Windows and external doors, including bifolds if chosen
- Building control inspections and completion certificate
Local housing and a single-storey extension
Cardiff has large areas of bay-fronted Victorian and Edwardian terraces in districts such as Roath, Canton and Cathays, plus interwar suburbs, post-war estates and modern flats around Cardiff Bay. Penarth has Victorian villas, Barry mixes terraces with newer estates, and Vale of Glamorgan villages are often built of local limestone.
Mild but wet, with coastal exposure along the Severn estuary and Bristol Channel affecting render, roofline and windows.
For a single-storey extension in Llantwit Major, this means checking things like wall construction, roof structure and existing services before we put a figure on paper.
Do you need permission in Llantwit Major?
For anyone in Llantwit Major, the relevant framework is Wales's. The summary below is general, so we always contact the council about your address before putting a price in writing.
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.
What happens after you get in touch?
Free site survey
A free survey comes first. It gives us what we need to price a single-storey extension properly, including dimensions, existing materials and access for deliveries, and gives you the chance to ask anything you like.
Your fixed price
Next you receive a written quote with a fixed price for the agreed specification. It lists what is included, what is not, and how payments are staged, so you can compare it properly.
Dates and permissions
Before anyone starts, we confirm the programme in writing, check whether consents are required and arrange deliveries. If a skip or scaffolding on the road needs a permit, we apply for it.
Finish and handover
On site, the agreed plan is followed and any change is put in writing first. At completion we do a final clean, go through the snagging list with you and leave you with the relevant documents.
Why homeowners choose us
Single-storey extensions in Llantwit Major: questions
Do I need an architect for an extension?
You need proper drawings for an extension, but not always a full architect service. A designer or architectural technician can produce planning and building regulations drawings, and a structural engineer provides beam and foundation calculations. If you already have drawings, we price from them. If not, we can arrange the drawings and calculations as part of the project so everything is coordinated from the start.
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.
Do you cover Bridgend, Barry and Porthcawl?
Yes. As well as Llantwit Major, we cover Bridgend, Barry and Porthcawl and the rest of South Glamorgan. 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 happens at the survey?
We visit your home at a time that suits you, look at the area involved, take measurements and check access, condition and any services that might be affected. We talk through what you want from a single-storey extension, explain the options and answer questions. There is no charge and no obligation; afterwards we send a written quote.
What is the Party Wall Act and does it apply to me?
The Party Wall etc. Act 1996 applies in England and Wales only. In England and Wales, it requires you to give notice to neighbours before certain work on or near a shared wall, such as digging foundations within 3m of their building and deeper than its footings. Neighbours can agree or appoint a surveyor. Scotland and Northern Ireland have no equivalent Act, though general rights still apply. We identify whether notices are needed during the survey.
Also covering areas around Llantwit Major
From CF61 to the edges of Llantwit Major and on into Bridgend, Barry and Porthcawl, we can arrange a site visit and a written quote for your project, planned around dates that work for you.