Covering Preston
We work in Preston (PR0, PR1, PR11) and the places around it, including Leyland, Chorley and Blackburn.
Homes in the North West
Across the North West, Victorian terraces, inter-war semis and modern estates all feature, and brick or stone matching is chosen to suit each street.
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.
- Damp and structural survey
- Waterproofing design and installation
- Underpinning or lowering the floor where needed
How much should I budget for a basement conversion?
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 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?
- Groundwater levels drive the waterproofing design and cost.
- New basements nearly always involve the Party Wall Act in England and Wales.
How does the project run?
- Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
- Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
- 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.
Basement and cellar conversions: common questions
How much does a basement conversion cost?
Converting an existing cellar costs about £1,900 to £3,000 per square metre including VAT. A new excavated basement is around £4,200 to £6,600 per square metre.
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 Preston?
Yes. Preston is within our coverage for basement and cellar conversions, along with nearby Leyland and Chorley.
Other towns nearby
- Basement and cellar conversions in Leyland
- Basement and cellar conversions in Chorley
- Basement and cellar conversions in Blackburn
- Basement and cellar conversions in Darwen
Learn more about basement and cellar conversions, or see every project we cover in Preston.

