Basement and cellar conversions in Trowbridge

Covering Trowbridge

Trowbridge sits 25 miles south-west of Swindon, with Bath 8 miles to the north-west and Frome 8 miles to the south-west.

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 goes into a basement conversion?

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.

Underpinning or lowering the floor where needed
Ventilation, heating and electrics
Finished floors, walls and ceilings

How much should I budget for a basement conversion?

What basement and cellar conversions typically cost. These are guide ranges; the written quote for your house replaces them.

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 England?

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. Digging a new basement or adding a lightwell often does, and many councils have basement policies.

What should I think about before starting?

New basements nearly always involve the Party Wall Act in England and Wales.
A pump for the drainage system needs a battery back-up.

From first call to completion

Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
Construction and completion. One site lead co-ordinates every trade through to the building control certificate.

Questions about a basement conversion in Trowbridge

Does a cellar conversion need planning permission?

Usually not if nothing changes outside. New basements and lightwells often do.

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 do I get a price for basement and cellar conversions in Trowbridge?

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

Other towns nearby

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