Covering Northampton
We work in Northampton (NN1) and the places around it, including Wellingborough, Towcester and Daventry.
Homes in the East Midlands
The East Midlands combines red-brick terraces in the cities with a lot of post-war and modern estate housing, so rear extensions, garage conversions and loft conversions are all common.
What is included in a basement conversion in Northampton?
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
- Lightwells and windows for daylight and escape
What is the guide price for a basement conversion in Northampton?
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 Northampton?
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?
- Groundwater levels drive the waterproofing design and cost.
- Headroom of about 2.1 m or more is needed, which may mean lowering the floor.
What happens after I enquire?
- Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
- Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
- Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
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.
Will my neighbours be affected?
New basements usually need party wall agreements. We handle the notices and surveyors.
Do you work in Northampton?
Yes. Northampton is within our coverage for basement and cellar conversions, along with nearby Wellingborough and Towcester.
Basement and cellar conversions in nearby towns
- Basement and cellar conversions in Wellingborough
- Basement and cellar conversions in Towcester
- Basement and cellar conversions in Daventry
- Basement and cellar conversions in Rushden
Learn more about basement and cellar conversions, or see every project we cover in Northampton.