What is ASTM D5957?
ASTM D5957 is a guide for testing the watertightness of installed horizontal waterproofing membranes — the sheet or fluid-applied membranes installed on plaza decks, podium slabs, parking structures, green roofs, and similar assemblies. Flood testing involves ponding water on the membrane surface to a specified depth for a defined period and then monitoring the area below the slab for any water that penetrates through the membrane system.
The principle is simple: if water ponds on the surface and appears below the slab (dripping through a ceiling, appearing at drain connections, or detected by moisture sensors), there is a breach in the waterproofing system. D5957 is a guide rather than a test method — it provides a framework for flood testing but allows flexibility in the specific procedures, ponding depth, and monitoring methods appropriate to each installation.
Flood testing is most effective and most practical when performed before overburden — paving, pavers, growing medium, or concrete topping — is placed over the membrane. Once the overburden is in place, the membrane is inaccessible, and a flood test failure can be very difficult and expensive to investigate and repair. Cx Associates strongly recommends flood testing as a standard component of the building enclosure commissioning scope on any project with horizontal waterproofing.
