Covering St Albans
Our coverage around St Albans (AL1, AL3) also includes Harpenden, Hatfield and Hemel Hempstead.
Homes in the East of England
The East of England has a large stock of post-war and modern estate housing alongside period homes in market towns, which makes garage conversions, single-storey extensions and loft conversions popular.
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
How much does a basement conversion cost in St Albans?
Guide prices for basement and cellar conversions, including VAT where it applies. Your fixed price is confirmed in writing after the survey.
| 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 |
What approvals does a basement conversion need in England?
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?
- Groundwater levels drive the waterproofing design and cost.
- New basements nearly always involve the Party Wall Act in England and Wales.
How does the project run?
- Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
- Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
- Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
- Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.
What people ask before starting
How long does it take?
About 6 to 12 weeks for a cellar conversion and 16 to 30 weeks for a new basement.
Will my neighbours be affected?
New basements usually need party wall agreements. We handle the notices and surveyors.
How do I get a price for basement and cellar conversions in St Albans?
Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.
Basement and cellar conversions in nearby towns
- Basement and cellar conversions in Harpenden
- Basement and cellar conversions in Hatfield
- Basement and cellar conversions in Hemel Hempstead
- Basement and cellar conversions in Welwyn Garden City
Learn more about basement and cellar conversions, or see every project we cover in St Albans.