What is a basement conversion?

A basement conversion turns an existing cellar into living space, or excavates a new basement under the house or garden. Waterproofing, structural support and daylight are the main design challenges.
How much does a basement conversion cost in Houghton-Le-Spring?
In Houghton-Le-Spring, a basement conversion typically costs £1,700–£2,900 per m² for converting an existing cellar, including VAT at 20% (standard rate). For a typical 30 m² project that is roughly £51,000–£87,000. Prices across the North East are typically 10% below the UK average for this kind of work, which is reflected in the range for Houghton-Le-Spring. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (21 m²) | £35,500–£61,000 |
| Typical project (30 m²) | £51,000–£87,000 |
| Larger project (42 m²) | £71,500–£122,000 |
| Rate per m² | £1,700–£2,900 |
The biggest cost drivers are:
- Floor lowering and underpinning
- Lightwells
- Existing cellar or new excavation
- Party wall surveyor fees
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a basement conversion in Houghton-Le-Spring?
Whether you need planning permission depends on your house and its location in England. In England converting an existing cellar with no external change usually does not need planning permission. New excavation, lightwells and changes to the front often do, and some councils, particularly in London, have specific basement policies.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
On a typical basement conversion we handle:
- Lightwells and windows
- Structural and ground survey
- Underpinning or new structure where needed
- Insulation, ventilation and drainage pumps
- Party wall notices
- Building control sign-off
How long does it take?
Build time is typically 8 to 16 weeks for a cellar conversion; longer for new excavation. Allow time beforehand for drawings and approvals, usually 3 to 5 months.
Building in Houghton-Le-Spring
Across the North East, colliery-era terraces and newer estates sit side by side, so the right project depends on the house type.
Houghton-Le-Spring sits in Tyne and Wear, about 11 miles south-east of Newcastle upon Tyne. We cover the whole of Houghton-Le-Spring, including postcodes DH4.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about basement conversions in Houghton-Le-Spring
Can a basement be a bedroom?
Yes, with a suitable escape route such as a lightwell window or protected stair.
How long does it take?
A cellar conversion takes around 8 to 16 weeks; new basements take longer.
How do you keep a basement dry?
With a waterproofing system designed to BS 8102, typically a cavity drain membrane with a sump pump, or a tanking system.
Do you build basement conversions in Houghton-Le-Spring?
Yes. We build basement conversions across Houghton-Le-Spring, including postcodes DH4. Every project starts with a free home visit.
How much does a basement conversion cost in Houghton-Le-Spring?
In Houghton-Le-Spring, a basement conversion typically costs £1,700–£2,900 per m² for converting an existing cellar, including VAT at 20% (standard rate). A typical 30 m² project comes to roughly £51,000–£87,000. Your fixed price depends on the survey and drawings.
