Covering Caerphilly
Our coverage around Caerphilly (CF83) also includes Whitchurch, Pontypridd and Cardiff.
Homes in Gwent
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 Caerphilly?
A basement conversion turns an existing cellar into dry, usable rooms, or excavates a new basement under a house. Converting an existing cellar is far simpler and cheaper than digging a new one, and often does not need planning permission.
- Planning and building regulations checks under Welsh rules
- Underpinning or lowering the floor where needed
- Ventilation, heating and electrics
How much does a basement conversion cost in Caerphilly?
Typical ranges for basement and cellar conversions. Ground conditions, access and specification move the final figure, which we fix in writing before work starts.
| 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 |
Do you need permission for a basement conversion in Caerphilly?
In Wales the planning rules, including what counts as permitted development, are set by the Welsh Government, and Welsh building regulations differ in places from England’s. We check both against your house before drawings are finalised, and handle party wall notices where needed.
In Wales an existing cellar conversion usually does not need planning permission; new excavation and lightwells may.
What should I think about before starting?
- 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.
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.
- Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
Your questions answered
Does a cellar conversion need planning permission?
Usually not if nothing changes outside. New basements and lightwells often do.
Will my neighbours be affected?
New basements usually need party wall agreements. We handle the notices and surveyors.
Who deals with the council for a project in Caerphilly?
We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.
Basement and cellar conversions in nearby towns
- Basement and cellar conversions in Whitchurch
- Basement and cellar conversions in Pontypridd
- Basement and cellar conversions in Cardiff
- Basement and cellar conversions in Newport
Learn more about basement and cellar conversions, or see every project we cover in Caerphilly.