Basement & Cellar Tanking
Basements and cellars sit below ground, so keeping them dry means holding back water pressure from the surrounding soil. Tanking and cavity drain membrane systems waterproof the space structurally, turning a damp, unusable cellar into dry storage or a proper habitable room.
Quick answer
Basement & Cellar Tanking typically starts from £1500 — from £1,500 — quoted per project after survey, as it varies a lot by structure. We confirm a fixed written price after a survey, before any work starts.
What basement tanking involves
There are two main approaches, and the right one depends on the structure and how you'll use the space. Tanking applies a waterproof barrier directly to the walls and floor to hold water out; a cavity drain membrane instead manages any water that gets in, channelling it to a drainage point or sump. We survey the cellar and recommend the system that suits it rather than a one-size-fits-all fix.
Basement waterproofing is the most project-specific thing we do, which is why it's always quoted individually after a damp survey rather than from a price list. It often goes hand in hand with penetrating damp treatment where water is getting in through the structure, and any affected timber is dealt with through woodworm and timber treatment. Done properly, waterproofing a basement is one of the most cost-effective ways to add genuinely usable floor space to a property.
What's included in every basement tanking job
- ✓Tanking or cavity drain membrane, chosen to suit the structure
- ✓Drainage and sump systems where needed
- ✓Suitable for storage or full habitable conversion
- ✓Quoted individually after a full survey
Get a survey for basement tanking
Book a Free SurveyWhatsApp +44 7415 016237Check if we cover your area →When you might need basement tanking
The most common situations we're called out for — if yours isn't listed, send a couple of photos through the contact form and we'll tell you exactly how we'd handle it.
A damp or flooding cellar
A basement that’s wet, smells musty or takes on water and can’t currently be used.
Converting a cellar
Turning a below-ground space into a habitable room, gym, utility or storage that needs to stay dry.
Water under pressure
Standing water or damp coming through basement walls and floors from the surrounding ground.
How It Works
- 1
Book a free damp survey
Tell us what you’re seeing — a tide mark, black mould, blown plaster or a survey that flagged damp. We arrange a visit, usually within a few days.
- 2
We diagnose the real cause
On site we identify whether it’s rising, penetrating or condensation damp (they’re treated completely differently) and give you a clear, honest explanation.
- 3
You get a fixed written quote
A clear, itemised price for the recommended work — no pressure, no vague estimates that move on the day, and no charge for the survey on standard jobs.
- 4
We treat it and guarantee it
The work is carried out to industry standards, the area is left clean and ready to redecorate, and the treatment is backed by a written workmanship guarantee.
Damp Proofing Price Guide
Indicative pricing — every job gets a fixed, written quote after a survey. No hidden extras.
Damp survey & report
diagnosis
Free
Free for straightforward jobs; a detailed independent survey report is available for mortgage or purchase cases.
DPC injection (per wall)
rising damp
from £350
Chemical damp-proof course injection to a single affected wall — priced by length and access.
Damp-proof re-plaster
per room
from £600
Salt-resistant re-plastering after treatment, so the wall can be redecorated cleanly.
Basement / cellar tanking
waterproofing
from £1500
Structural waterproofing (tanking or cavity membrane) — quoted per project after survey.
Often needed alongside basement tanking
Damp problems rarely come alone — these related treatments are commonly part of the same job, for example damp surveys & reports, penetrating damp treatment and woodworm & timber treatment.
Where we cover basement tanking
We provide basement & cellar tanking right across England, Wales and Scotland as part of our regular damp proofing coverage, including busy counties such as Greater London, Greater Manchester, Kent, Devon, Staffordshire, West Midlands, Hampshire and Merseyside. Not sure if we reach you? Check the full areas we cover or just send your postcode with your enquiry.
Basement Tanking — frequently asked questions
Do you tank basements and cellars?
Yes — we waterproof basements and cellars using tanking slurry or a cavity drain membrane system depending on the structure and how the space will be used. This is quoted individually after a survey as it varies a lot property to property.
How much does damp proofing cost in your area?
Most single-wall damp-proof course treatments in your area start from around £350, with a full room including salt-resistant re-plastering nearer £600–£1,200 depending on size and access. We always confirm a fixed price in writing after a survey — no hidden extras.
How quickly can you survey a property in your area?
We cover your area regularly and can usually arrange a survey within a few working days — sooner for urgent cases such as a sale falling through on a damp report.
Is your damp proofing work guaranteed?
Yes — damp-proof course treatments are carried out to industry standards and backed by a written workmanship guarantee. We confirm the exact terms and length in your quote before any work starts.
Damp is treated by cause, not by symptom: rising, penetrating and condensation damp look similar but need completely different treatments, which is why every job starts with a proper survey and diagnosis before any work is quoted.
Book a free survey for basement tanking
Tell us about the damp and your postcode — we'll arrange a survey and a fixed written quote.