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 Congleton?
In Congleton, 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. That range is adjusted for the North West, where domestic building work typically costs around 6% below the national average. 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:
- Floor lowering and underpinning
- Lightwells
- Existing cellar or new excavation
- Party wall surveyor fees
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 Congleton?
Before anything is built in Congleton, we confirm which approvals apply 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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
The work we manage on a basement conversion:
- Waterproofing design (tanking or cavity drain membrane)
- Underpinning or new structure where needed
- Insulation, ventilation and drainage pumps
- Party wall notices
- 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. Before that, surveys, drawings and approvals usually take 3 to 5 months, longer if the council asks for changes.
Building in Congleton
The North West has many brick terraces and inter-war semis, where kitchen extensions and dormer loft conversions add space without moving.
Congleton sits in Cheshire, about 11 miles north of Stoke-on-Trent. We cover the whole of Congleton, including postcodes CW12.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 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 Congleton
How much does a basement conversion cost in Congleton?
In Congleton, 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.
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.
Who approves a basement conversion in Congleton?
Planning matters in Congleton go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Do I need party wall agreements?
In England and Wales, excavating near a neighbour’s foundations usually triggers the Party Wall etc. Act 1996.