Covering Hampshire
Our basement and cellar conversions service in Hampshire covers Southampton, Portsmouth, Basingstoke and Gosport and more.
Homes in the South East
Many South East homes are inter-war or post-war semis and detached houses with room for rear and side extensions, while historic town centres and villages bring conservation area and listed building controls.
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.
- Damp and structural survey
- Underpinning or lowering the floor where needed
- Ventilation, heating and electrics
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?
English projects need planning clearance from the local council, building regulations sign-off from building control, and party wall notices where the work is on or near a shared boundary. We prepare and manage all three.
Converting an existing cellar with no external changes usually does not need planning permission in England.
What can change the price or programme?
- 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.
How does the project run?
- Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
- 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 Hampshire
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.
Do you work in Hampshire?
Yes. Hampshire is within our coverage for basement and cellar conversions, along with nearby Southampton and Portsmouth.
Also covering
- Basement and cellar conversions in Southampton
- Basement and cellar conversions in Portsmouth
- Basement and cellar conversions in Basingstoke
- Basement and cellar conversions in Gosport
- Basement and cellar conversions in Waterlooville
- Basement and cellar conversions in Farnborough
- Basement and cellar conversions in Eastleigh
- Basement and cellar conversions in Winchester
- Basement and cellar conversions in Havant
- Basement and cellar conversions in Andover
- Basement and cellar conversions in Fareham
- Basement and cellar conversions in Fleet
- Basement and cellar conversions in Totton
- Basement and cellar conversions in New Milton
Learn more about basement and cellar conversions, or see every project we cover in Hampshire.