Basement and cellar conversions in Llantwit Major

Covering Llantwit Major

Alongside Llantwit Major, we also cover Cowbridge, Bridgend (8 miles to the north-west) and Barry.

Homes in South Glamorgan

Across Wales you find valley terraces, coastal towns, rural stone houses and newer estates, so access, slopes and local materials all feature in the design.

What does a basement conversion involve?

Everything below ground depends on keeping water out. We design the waterproofing system (usually a cavity drain membrane with a pump, or tanking) to the relevant British Standard guidance, then add insulation, ventilation, light and an escape route. New basements involve underpinning and a party wall process and are designed with a structural engineer.

Planning and building regulations checks under Welsh rules
Waterproofing design and installation
Ventilation, heating and electrics

What is the guide price for a basement conversion in Llantwit Major?

Use these ranges to budget for basement and cellar conversions; the survey turns them into a fixed price for the agreed specification.

Basement and cellar conversions	Guide price incl. VAT
Existing cellar conversion	£1,900 to £3,000 per m²
New basement excavation	£4,200 to £6,600 per m²

What approvals does a basement conversion need in Wales?

Welsh projects need planning clearance from the council under Welsh rules, building regulations approval under the Welsh approved documents, and party wall notices where the work affects a neighbour’s wall or foundations.

In Wales an existing cellar conversion usually does not need planning permission; new excavation and lightwells may.

What should Llantwit Major homeowners check first?

Groundwater levels drive the waterproofing design and cost.
Headroom of about 2.1 m or more is needed, which may mean lowering the floor.

What happens after I enquire?

Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
Construction and completion. One site lead co-ordinates every trade through to the building control certificate.

Your questions answered

How do you keep a basement dry?

With a designed waterproofing system, usually a cavity drain membrane draining to a pump, sometimes combined with tanking.

How long does it take?

About 6 to 12 weeks for a cellar conversion and 16 to 30 weeks for a new basement.

How do I get a price for basement and cellar conversions in Llantwit Major?

Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.

Basement and cellar conversions near Llantwit Major

Learn more about basement and cellar conversions, or see every project we cover in Llantwit Major.