Covering Calne
Our coverage around Calne (SN11) also includes Chippenham, Devizes and Corsham.
Homes in the South West
Homes in the South West range from coastal and rural properties in stone and slate to city terraces and modern estates, so extensions are designed to match the local materials.
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.
- Waterproofing design and installation
- Underpinning or lowering the floor where needed
- Ventilation, heating and electrics
What is the guide price for a basement conversion in Calne?
Indicative costs for basement and cellar conversions. London and the South East usually sit towards the top of each range.
| 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 Calne?
In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it applies.
Converting an existing cellar with no external changes usually does not need planning permission in England.
What can change the price or programme?
- New basements nearly always involve the Party Wall Act in England and Wales.
- A pump for the drainage system needs a battery back-up.
What are the steps?
- 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.
- Construction and completion. One site lead co-ordinates every trade through to the building control certificate.
What people ask before starting
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.
Who deals with the council for a project in Calne?
We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.
Other towns nearby
- Basement and cellar conversions in Chippenham
- Basement and cellar conversions in Devizes
- Basement and cellar conversions in Corsham
- Basement and cellar conversions in Trowbridge
Learn more about basement and cellar conversions, or see every project we cover in Calne.

