Negative-side waterproofing is used when the outside cannot be reached, such as elevator pits, tunnels and existing basements. Water still saturates the concrete and pushes against the coating from behind, so only materials that bond into the concrete, like crystalline and cementitious coatings, work reliably. Membranes and paints usually blister and delaminate on the negative side.
Elevator pit's leaking and it's all negative side, so grind it, pack the cracks and crystalline the whole pit.
Also heard as
- negative-side waterproofing
- dry side
Related terms
Positive side
The face of a wall or slab that touches the water source, where waterproofing works best.
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.
Hydrostatic pressure
Pressure from standing groundwater against a wall or slab, rising with the depth of water above that point.