Waterproofing
Cellar tanking
Cementitious cellar tanking considered against substrate condition, pressure and intended use.
Why diagnosis matters
Treat the cause, then repair the damage
Tanking forms a barrier bonded to the structure. Success relies on preparation, sound junctions and a substrate capable of supporting the system under expected water pressure.
Technical review
Dan, Director / Surveyor
Last reviewed: July 2026. Advice is general until the property, access and visible evidence have been assessed.
Guarantee & aftercare
Written guarantee terms are matched to qualifying work, with inclusions, exclusions and aftercare explained before acceptance.
What we consider
Possible causes and lookalikes
Lateral ground moisture
Hydrostatic pressure
Cracks and weak backgrounds
Failed historic coatings
Inspection method
A clear work sequence
Step 1
Inspect and test substrate
Step 2
Remove incompatible finishes
Step 3
Detail junctions and penetrations
Step 4
Apply system and control curing
Scope boundaries
Honest about what the work does—and does not—cover
Tanking can be inappropriate for weak or moving structures. Structural uncertainty and complex design are referred.
Common questions
About cellar tanking
Can tanking fail?+
Yes. Poor preparation, movement, pressure, weak backgrounds and missed junctions can all lead to failure.
Can I plaster directly over it?+
Only with a compatible specification and after required curing. The chosen finish must not compromise the system.
Does it need maintenance?+
Barrier systems have fewer mechanical parts than drained systems, but the space and any defects still require inspection.
Related services
Continue your investigation
Next step
Claim your complimentary survey before choosing a treatment
Tell us what you can see, when it changes and where the property is. Photographs can help us triage the next step.