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 Fleetwood?
In Fleetwood, a basement conversion typically costs £1,800–£3,000 per m² for converting an existing cellar, including VAT at 20% (standard rate). For a typical 30 m² project that is roughly £54,000–£90,000. Building costs in the North West run about 6% below the UK average, and the figures for Fleetwood are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (21 m²) | £38,000–£63,000 |
| Typical project (30 m²) | £54,000–£90,000 |
| Larger project (42 m²) | £75,500–£126,000 |
| Rate per m² | £1,800–£3,000 |
What moves the price most:
- Existing cellar or new excavation
- Ground water and access
- Floor lowering and underpinning
- Party wall surveyor fees
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a basement conversion in Fleetwood?
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.
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.
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:
- Waterproofing design (tanking or cavity drain membrane)
- Building control sign-off
- Party wall notices
- Structural and ground survey
- Insulation, ventilation and drainage pumps
- Lightwells and windows
How long does it take?
Build time is typically 8 to 16 weeks for a cellar conversion; longer for new excavation. Before that, surveys, drawings and approvals usually take 3 to 5 months, longer if the council asks for changes.
Building in Fleetwood
The North West has many brick terraces and inter-war semis, where kitchen extensions and dormer loft conversions add space without moving.
We work across Fleetwood and neighbouring areas such as Thornton-Cleveleys, Poulton-le-Fylde and Fylde. Postcodes we cover in Fleetwood include FY7.
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
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about basement conversions in Fleetwood
Do I need party wall agreements?
In England and Wales, excavating near a neighbour’s foundations usually triggers the Party Wall etc. Act 1996.
Who approves a basement conversion in Fleetwood?
Planning matters in Fleetwood go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
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 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 Fleetwood?
In Fleetwood, a basement conversion typically costs £1,800–£3,000 per m² for converting an existing cellar, including VAT at 20% (standard rate). A typical 30 m² project comes to roughly £54,000–£90,000. Your fixed price depends on the survey and drawings.
