Llantwit Major, Cardiff and the Vale
Single-storey rear extension in Llantwit Major
For homes in Llantwit Major, a single-storey rear extension is often the simplest way to gain space without moving. Ground-floor space across the back of the house, usually for a kitchen, dining or family room. We take it from survey to completion certificate.
Llantwit Major sits in Cardiff and the Vale, with postcode districts including CF61. A depth of 3 to 4 metres keeps many single-storey rear extensions in Llantwit Major within permitted development, subject to the house's planning history.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a single-storey rear extension cost in Llantwit Major?
For Llantwit Major we work from the Wales rate: £1,770–£2,880 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 |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £21,000–£34,500 |
| 4 m wide × 5 m deep (20 m²) | £35,500–£57,500 |
| 4 m wide × 6 m deep (24 m²) | £42,500–£69,000 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission for a single-storey rear extension in Llantwit Major?
Whether your single-storey rear extension in Llantwit Major needs a planning application depends on its size, your house and any local restrictions.
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.
Conservation areas, National Parks and National Landscapes restrict permitted development in Wales, and listed buildings need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Llantwit Major like to extend?
Llantwit Major has Victorian terraces near the centre and semis further out. Welsh permitted development allows up to 4 metres at the rear for many houses.
How a single-storey rear extension in Llantwit Major comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Single-storey rear extensions near Llantwit Major
From Llantwit Major, the nearest places we also cover are Bridgend (7.6 miles) and Coity (8.2 miles).
- Single-storey rear extension in Bridgend
- Single-storey rear extension in Coity
- Single-storey rear extension in Barry
- Single-storey rear extension in Aberkenfig
- Single-storey rear extension in Llantrisant
Other work in Llantwit Major:
FAQ
Single-storey rear extension questions in Llantwit Major
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
Do you handle building control in Llantwit Major?
Yes. We apply to the council or a registered approver under the Welsh regulations and hand over the completion certificate.
Does it add value to the house?
Nationwide's October 2025 house price research found that a 10% increase in floor area is linked to about 5% higher value on average. It is a guide, not a promise; local agents can tell you what extended homes on your street sell for.
Can you match the brick or stone on my Llantwit Major house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
Do I need a party wall agreement?
In Wales, usually yes if the extension is on or near a shared boundary or close to a neighbour's foundations. We serve the notices.
How much does a single-storey rear extension cost in Llantwit Major?
As a guide, £1,770–£2,880 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £21,000–£34,500 at that rate. Your written price follows the survey.