Covering St Austell
St Austell is about 13 miles north-east of Truro. We also cover Bodmin (9 miles to the north), Truro and Falmouth.
Projects in Cornwall are taken on by arrangement, and any travel and accommodation costs for the team are shown openly in the quote.
Homes in the South West
In the South West, matching local stone, render or slate is often the main design question, and conservation areas and listed buildings are common in historic towns.
What goes into a basement conversion?
Everything below ground depends on keeping water out. We design the waterproofing system (usually a cavity drain membrane with a pump, or tanking) to the relevant British Standard guidance, then add insulation, ventilation, light and an escape route. New basements involve underpinning and a party wall process and are designed with a structural engineer.
- Lightwells and windows for daylight and escape
- Ventilation, heating and electrics
- Finished floors, walls and ceilings
What is the guide price for a basement conversion in St Austell?
Typical ranges for basement and cellar conversions. Ground conditions, access and specification move the final figure, which we fix in writing before work starts.
| Basement and cellar conversions | Guide price incl. VAT |
|---|---|
| Existing cellar conversion | £1,900 to £3,000 per m² |
| New basement excavation | £4,200 to £6,600 per m² |
Do you need permission for a basement conversion in St Austell?
English projects need planning clearance from the local council, building regulations sign-off from building control, and party wall notices where the work is on or near a shared boundary. We prepare and manage all three.
Converting an existing cellar with no external changes usually does not need planning permission in England.
What can affect a basement conversion?
- A pump for the drainage system needs a battery back-up.
- Headroom of about 2.1 m or more is needed, which may mean lowering the floor.
What happens after I enquire?
- Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
- Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
- Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
- Construction and completion. One site lead co-ordinates every trade through to the building control certificate.
Questions about a basement conversion in St Austell
Does a cellar conversion need planning permission?
Usually not if nothing changes outside. New basements and lightwells often do.
How long does it take?
About 6 to 12 weeks for a cellar conversion and 16 to 30 weeks for a new basement.
Do you work in St Austell?
Yes. St Austell is within our coverage for basement and cellar conversions, along with nearby Bodmin and Truro.
Basement and cellar conversions near St Austell
- Basement and cellar conversions in Bodmin
- Basement and cellar conversions in Truro
- Basement and cellar conversions in Falmouth
- Basement and cellar conversions in Redruth
Learn more about basement and cellar conversions, or see every project we cover in St Austell.

