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 Newquay?
In Newquay, a basement conversion typically costs £1,950–£3,250 per m² for converting an existing cellar, including VAT at 20% (standard rate). For a typical 30 m² project that is roughly £58,500–£97,500. Prices in the South West sit near the national average for this kind of work, and the range for Newquay reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (21 m²) | £41,000–£68,000 |
| Typical project (30 m²) | £58,500–£97,500 |
| Larger project (42 m²) | £82,000–£136,500 |
| Rate per m² | £1,950–£3,250 |
The main things that change the cost:
- Ground water and access
- Party wall surveyor fees
- Existing cellar or new excavation
- Floor lowering and underpinning
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 Newquay?
Approvals for a basement conversion in Newquay follow the rules for 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.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
From survey to sign-off, the job normally involves:
- Waterproofing design (tanking or cavity drain membrane)
- Lightwells and windows
- Party wall notices
- Underpinning or new structure where needed
- Electrics, heating and plastering
- Building control sign-off
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 Newquay
The South West mixes stone and render cottages with post-war and newer estates, and local materials matter more here when matching an extension.
Newquay sits in Cornwall, about 10 miles north of Truro. We cover the whole of Newquay, including postcodes TR7.
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 fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about basement conversions in Newquay
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 much does a basement conversion cost in Newquay?
In Newquay, a basement conversion typically costs £1,950–£3,250 per m² for converting an existing cellar, including VAT at 20% (standard rate). A typical 30 m² project comes to roughly £58,500–£97,500. Your fixed price depends on the survey and drawings.
Can a basement be a bedroom?
Yes, with a suitable escape route such as a lightwell window or protected stair.
Do you build basement conversions in Newquay?
Yes. We build basement conversions across Newquay, including postcodes TR7. Every project starts with a free home visit.
How long does it take?
A cellar conversion takes around 8 to 16 weeks; new basements take longer.