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 Gateshead?
In Gateshead, 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. That range is adjusted for the North East, where domestic building work typically costs around 10% below the national average. 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 |
What moves the price most:
- Ground water and access
- Lightwells
- Waterproofing system
- Floor lowering and underpinning
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a basement conversion in Gateshead?
The approval route for Gateshead is set by planning law 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
Handled as part of most basement conversions:
- Underpinning or new structure where needed
- Insulation, ventilation and drainage pumps
- Lightwells and windows
- Electrics, heating and plastering
- Structural and ground survey
- Party wall notices
How long does it take?
Expect 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 Gateshead
Across the North East, colliery-era terraces and newer estates sit side by side, so the right project depends on the house type.
Projects in Gateshead (DH98, NE8, NE82 and NE83) are surveyed in person before we quote, so the price reflects your actual property.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about basement conversions in Gateshead
Do I need party wall agreements?
In England and Wales, excavating near a neighbour’s foundations usually triggers the Party Wall etc. Act 1996.
Is new excavation worth it?
It can be in high-value areas, but costs are high. We give a feasibility view before design starts.
How long does a basement conversion take in Gateshead?
Typically 8 to 16 weeks for a cellar conversion; longer for new excavation. Design and approvals beforehand usually take 3 to 5 months.
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.
How much does a basement conversion cost in Gateshead?
In Gateshead, 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.
