Covering Maidenhead
We work in Maidenhead (SL6) and the places around it, including Slough, Windsor and Beaconsfield.
Homes in the South East
Housing across the South East mixes inter-war semis, post-war estates and older cottages in villages and market towns, so rear and side extensions, hip-to-gable lofts and garage conversions all come up regularly.
What is included in a basement conversion in Maidenhead?
A basement conversion turns an existing cellar into dry, usable rooms, or excavates a new basement under a house. Converting an existing cellar is far simpler and cheaper than digging a new one, and often does not need planning permission.
- Damp and structural survey
- Lightwells and windows for daylight and escape
- Finished floors, walls and ceilings
What is the guide price for a basement conversion in Maidenhead?
Indicative costs for basement and cellar conversions. London and the South East usually sit towards the top of each range.
| 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 |
Planning and building rules in Maidenhead
In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it applies.
Converting an existing cellar with no external changes usually does not need planning permission in England.
What should I think about before starting?
- Groundwater levels drive the waterproofing design and cost.
- Headroom of about 2.1 m or more is needed, which may mean lowering the floor.
What are the steps?
- Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
- Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
- Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
- Construction and completion. One site lead co-ordinates every trade through to the building control certificate.
Your questions answered
How much does a basement conversion cost?
Converting an existing cellar costs about £1,900 to £3,000 per square metre including VAT. A new excavated basement is around £4,200 to £6,600 per square metre.
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 Maidenhead?
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 Slough
- Basement and cellar conversions in Windsor
- Basement and cellar conversions in Beaconsfield
- Basement and cellar conversions in High Wycombe
Learn more about basement and cellar conversions, or see every project we cover in Maidenhead.

