Basement and cellar conversions in Stockton-on-Tees

Covering Stockton-on-Tees

Alongside Stockton-on-Tees, we also cover Billingham, Thornaby-on-Tees (3 miles to the south) and Middlesbrough.

Homes in the North East

Housing across the North East ranges from colliery terraces and Tyneside flats to suburban semis and modern estates, each with different options for extending.

What is 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.

Waterproofing design and installation
Underpinning or lowering the floor where needed
Lightwells and windows for daylight and escape

How much should I budget for a basement conversion?

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

What approvals does a basement conversion need in England?

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.

What should Stockton-on-Tees homeowners check first?

New basements nearly always involve the Party Wall Act in England and Wales.
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.
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.

Basement and cellar conversions: common questions

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.

Does a cellar conversion need planning permission?

Usually not if nothing changes outside. New basements and lightwells often do.

How do I get a price for basement and cellar conversions in Stockton-on-Tees?

Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.

Other towns nearby

Learn more about basement and cellar conversions, or see every project we cover in Stockton-on-Tees.