Substrate preparation
Blinding cleaned and levelled, protrusions removed, corners filleted.
PVC membrane tanking
A single welded envelope below ground — walls, floor and soffit as one continuous skin, tested before it is buried.
The problem
A basement that leaks cannot be fixed cheaply. Once the structure is backfilled and in service, the water path is on the outside and every repair is made from the wrong side of the concrete.
Coated systems depend on the thickness a crew achieved on the day, and there is no way to prove it before the excavation is closed. That is the gap this system removes.
What it is
Prefabricated PVC sheet, lapped and hot-air welded into a continuous membrane that wraps the entire below-grade envelope. No cold joints, no thickness variation, and — the part that matters — every seam is testable before backfill.
How it goes in
Six stages, all photographed on the same job. Very few contractors anywhere can show the whole sequence from their own work.
Sheet rolled out
Panels positioned and lapped to the specified overlap, floor first.
Seams welded
Hot-air wedge welding, twin-track with a test channel between the welds.
Detailing
Pipe penetrations, column bases, wall-to-floor junctions, day joints.
Flood test
The envelope filled and held. The verification step, and the one nobody else photographs.
In service
Protection layer, backfill, and the handover file with every weld test recorded.
Against the alternatives
Where PVC wins
- Not thickness-dependent — the sheet is manufactured to spec, not applied to it
- Every seam is testable before backfill, by air lance or vacuum box
- Accommodates structural movement without cracking
- One material across floor, wall and soffit — no junction between systems
Where it does not
- Needs careful detailing at every penetration — the weak points are the details, not the sheet
- Needs a competent welding crew; a bad weld is invisible until it leaks
- Not a repair method — installed before the structure is closed
- Higher up-front cost than a coating, recovered the first time a basement does not leak
What gets tested, and what you receive
- Weld continuity
- Air-lance or vacuum-box test on every seam, recorded by panel reference.
- Test channel pressure
- Twin-track welds pressurised and held; pass criteria recorded per run.
- Flood test
- Envelope filled and monitored for the specified duration before backfill.
- Handover file
- As-built panel layout, weld log, test results, material certificates.
To price it, send us
- Structural drawings of the below-grade envelope
- Water table level and any ground contamination data
- Programme — when the blinding is ready and when backfill is planned
- Photographs of the excavation as it stands today
Send us the problem and a photograph.
Most enquiries are answered the same day. Send the problem with a photograph, or look through the services first.