Basement and cellar conversions in Ashford, Surrey

Covering Ashford, Surrey

We work in Ashford, Surrey (TW15) and the places around it, including Staines, Feltham and Sunbury-on-Thames.

Homes in the South East

The South East has a lot of 1930s and post-war semi-detached housing, well suited to rear extensions and hip-to-gable loft conversions, alongside period properties in conservation areas that need a more careful design.

What is a basement conversion?

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.

Waterproofing design and installation
Lightwells and windows for daylight and escape
Ventilation, heating and electrics

What is the guide price for a basement conversion in Ashford, Surrey?

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

Do you need permission for a basement conversion in Ashford, Surrey?

Projects in England go through two separate checks. Planning (or confirmation that the work is permitted development) comes from the district, borough or unitary council, and building regulations approval comes from the council’s building control team or a registered building control approver. Where work touches a shared wall or digs near a neighbour’s foundations, the Party Wall etc. Act 1996 applies.

Converting an existing cellar with no external changes usually does not need planning permission in England. Digging a new basement or adding a lightwell often does, and many councils have basement policies.

What should I think about before starting?

New basements nearly always involve the Party Wall Act in England and Wales.
A pump for the drainage system needs a battery back-up.

From first call to completion

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.
Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.

Your questions answered

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.

Can you visit a house in Ashford, Surrey to quote?

Yes. After a short call we arrange a site visit to measure up and agree what the design needs to do, then send a written price.

Basement and cellar conversions in nearby towns

Learn more about basement and cellar conversions, or see every project we cover in Ashford.