Evaluation of Bentonite Clay for Waterproofing Foundation Walls Below Grade.

Bentonite clay panels and bentonite spray are evaluated for waterproofing the exterior surface of foundation walls below grade. The evaluation is based on a field letter survey and contacts with users, architects, and installers of bentonite panels and applicators of bentonite spray. Two installations were observed to provide first-hand data. Both bentonite systems performed favorably at a cost comparable to conventional systems, but lower than most elastomeric systems. Product information, including responses from the field, cost comparisons, and advantages and limitations for both materials, is given.