The workhorse type is a ribbed PVC or rubber profile set half in each pour. Hydrophilic strips swell when wet, bentonite strips swell into a gel, and crystalline or injection-hose systems are also used. They go at cold joints, wall-to-footing joints and around penetrations. A waterstop that is folded, displaced or left with an unwelded splice during the pour is a common hidden defect.
Waterstop on the wall-footing joint got kicked over during the pour, so expect a leak at that corner.
PVC waterstop splices must be heat welded, not taped, and every one is a checkpoint before the pour.
Also heard as
- water stop
Related terms
Cold joint
The seam where one concrete pour meets a later one, a classic leak path in below-grade walls and slabs.
Bentonite
A sodium clay that swells into a watertight gel when wet, used in panels, mats and strips for below-grade waterproofing.
Crystalline waterproofing
A cementitious treatment whose chemicals grow insoluble crystals inside concrete pores and cracks to block water.
Crack injection
Pumping polyurethane or epoxy into a leaking concrete crack through ports to seal it from the inside.