Covering Carmarthen
Our coverage around Carmarthen (SA31) also includes Llanelli, Ammanford and Pontarddulais.
Homes in Dyfed
Welsh homes include long terraces built into hillsides, stone cottages and modern estates, and sloping sites often shape how and where an extension can go.
What is included in a basement conversion in Carmarthen?
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.
- Waterproofing design and installation
- Underpinning or lowering the floor where needed
- Ventilation, heating and electrics
How much does a basement conversion cost in Carmarthen?
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 can affect a basement conversion?
- A pump for the drainage system needs a battery back-up.
- Headroom of about 2.1 m or more is needed, which may mean lowering the floor.
From first call to completion
- 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.
What people ask before starting
Does a cellar conversion need planning permission?
Usually not if nothing changes outside. New basements and lightwells often do.
How long does it take?
About 6 to 12 weeks for a cellar conversion and 16 to 30 weeks for a new basement.
Who deals with the council for a project in Carmarthen?
We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.
Basement and cellar conversions near Carmarthen
- Basement and cellar conversions in Llanelli
- Basement and cellar conversions in Ammanford
- Basement and cellar conversions in Pontarddulais
- Basement and cellar conversions in Tenby
Learn more about basement and cellar conversions, or see every project we cover in Carmarthen.