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 Nuneaton?
In Nuneaton, a basement conversion typically costs £1,850–£3,100 per m² for converting an existing cellar, including VAT at 20% (standard rate). For a typical 30 m² project that is roughly £55,500–£93,000. Building costs in the West Midlands are close to the UK average, so the figures for Nuneaton are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (21 m²) | £39,000–£65,000 |
| Typical project (30 m²) | £55,500–£93,000 |
| Larger project (42 m²) | £77,500–£130,000 |
| Rate per m² | £1,850–£3,100 |
The main things that change the cost:
- Existing cellar or new excavation
- Ground water and access
- Floor lowering and underpinning
- Waterproofing system
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 Nuneaton?
Here is how the rules work for a basement conversion 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
The work we manage on a basement conversion:
- Electrics, heating and plastering
- Lightwells and windows
- Waterproofing design (tanking or cavity drain membrane)
- Structural and ground survey
- Building control sign-off
- 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 Nuneaton
The West Midlands has large numbers of 1930s semis and Victorian terraces, which suit rear extensions, side extensions and dormer loft conversions.
Our Nuneaton coverage includes postcode districts CV11, and we also work in nearby places such as Bedworth, Hinckley and Earl Shilton.
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
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about basement conversions in Nuneaton
Do I need party wall agreements?
In England and Wales, excavating near a neighbour’s foundations usually triggers the Party Wall etc. Act 1996.
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.
Who approves a basement conversion in Nuneaton?
Planning matters in Nuneaton go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
How long does it take?
A cellar conversion takes around 8 to 16 weeks; new basements take longer.
How much does a basement conversion cost in Nuneaton?
In Nuneaton, a basement conversion typically costs £1,850–£3,100 per m² for converting an existing cellar, including VAT at 20% (standard rate). A typical 30 m² project comes to roughly £55,500–£93,000. Your fixed price depends on the survey and drawings.
