Basement Waterproofing Cost in London (2026)
Basement Waterproofing Cost in London: a 40 m² basement tanking / waterproofing scheme in London costs around £27,000–£41,000 including VAT, or about £819 per m². These are 2026 benchmark figures for planning your budget — your exact cost depends on finish, site conditions, access and structural work.
Typical cost range in London
£27,000 to £41,000 including VAT, around £819 per m². Based on a 40 m² basement tanking / waterproofing scheme. Figures last reviewed Q2 2026.
What's included
- Preliminaries: £1,119 (3.4% of typical cost)
- Demolition / strip out: £2,417 (7.4% of typical cost)
- Groundworks: £4,834 (14.7% of typical cost)
- Substructure: £8,459 (25.8% of typical cost)
- Superstructure: £1,208 (3.7% of typical cost)
- Roofing: £483 (1.5% of typical cost)
- Windows and doors: £0 (0% of typical cost)
- M&E: £1,208 (3.7% of typical cost)
- Internal finishes: £1,933 (5.9% of typical cost)
- External works: £725 (2.2% of typical cost)
- Contingency: £2,239 (6.8% of typical cost)
- Professional fees: £2,686 (8.2% of typical cost)
- VAT: £5,462 (16.7% of typical cost)
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Frequently asked questions
How much does a basement waterproofing project cost in London?
In London, a 40 m² basement tanking / waterproofing scheme typically costs £27,000–£41,000 including VAT, which works out at roughly £819 per m². The final figure depends on the finish you choose, ground and site conditions, access, and how much structural work is involved.
Why is a basement waterproofing project more expensive in London than the UK average?
Build Hub applies a regional cost multiplier for London that reflects local labour rates, material logistics and demand. Prices in higher-cost regions such as London and the South East run well above the national average, while much of the North, Wales and Scotland sits below it.
What does this basement waterproofing project estimate include?
The range covers construction works, a main-contractor margin, a contingency allowance and professional fees. It excludes VAT where shown separately, plus fittings, fees and surveys listed in the exclusions. It is a planning-stage benchmark, not a fixed quotation.
Do I pay VAT on a basement waterproofing project?
Most basement waterproofing project work is standard-rated at 20% VAT. Some energy-saving measures and works to listed or long-empty properties can qualify for a reduced or zero rate — check the specifics with your contractor and HMRC.
Do I need planning permission for a basement waterproofing project in London?
Many smaller projects fall under permitted development, but limits vary by property type, location and whether you're in a conservation area. Use Build Hub's free planning guidance to check your specific address before you budget.
How can I get a more accurate basement waterproofing project quote?
Run your own numbers with Build Hub's free cost estimator — it adjusts for your exact postcode, size, finish, access and site conditions in seconds, with no account required. You can then invite vetted local contractors to tender.