Covering Washington
Washington sits 6 miles south-east of Newcastle upon Tyne, with Chester-le-Street 4 miles to the south-west and Felling 4 miles to the north-west.
Homes in the North East
In the North East, terraces, semis and bungalows all offer room to extend, with stone-built villages and conservation areas in parts of County Durham and Northumberland.
What does a basement conversion involve?
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.
- Damp and structural survey
- Waterproofing design and installation
- Underpinning or lowering the floor where needed
What is the guide price for a basement conversion in Washington?
What basement and cellar conversions typically cost. These are guide ranges; the written quote for your house replaces them.
| 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 |
How is a basement conversion approved in Washington?
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. Digging a new basement or adding a lightwell often does, and many councils have basement policies.
What can change the price or programme?
- Groundwater levels drive the waterproofing design and cost.
- New basements nearly always involve the Party Wall Act in England and Wales.
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.
- We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
- Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
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.
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 Washington?
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 near Washington
- Basement and cellar conversions in Chester-le-Street
- Basement and cellar conversions in Felling
- Basement and cellar conversions in Houghton-le-Spring
- Basement and cellar conversions in Hebburn
Learn more about basement and cellar conversions, or see every project we cover in Washington.

