Standards Development for Impermeable, Constructible, and Durable Waterproofing

ABSTRACT: Building owners’ expectations for waterproofing systems are simple. Waterproofing must prevent the passage of water (impermeability), must be capable of successful installation under typical construction conditions (constructability), and must continue to provide waterproofing for the life of the structure (durability). The realization of these expectations is thwarted, in part, by a lack of consensus on how these features are defined, tested, and compared to performance-based criteria. This investigation includes waterproofing materials commonly used on plazas and below-grade walls. The authors discuss important properties of waterproofing and review the requirements of standards for waterproofing systems.

The results of testing bentonite and cold liquid-applied waterproofing are reported. In conclusion, the authors suggest improvements in standards.

KEYWORDS: waterproofing, impermeability, constructability, durability, bentonite, liquid-applied Introduction

Buildings are often designed to utilize below-grade space beneath the building footprint and plazas. Occupied above-grade building spaces are sometimes topped with terraces and “green” roofs. Each of these areas must be protected from water intrusion by a waterproofing system.

When waterproofing systems fail, unsightly stains occur, building contents are damaged, mold can grow, occupied spaces may be unwillingly abandoned, and the structure deteriorates. Waterproofing sys­tems may be completely inaccessible for repair, as with deep below-grade walls, or accessible at a high cost, as when plaza finishes and planters must be removed.

The authors are often called upon to investigate waterproofing system failures. We find that it is often challenging to restore waterproofing systems to the same level of reliability that should be provided by a new installation. The cost of repairing a widespread waterproofing failure is likely to far exceed the initial cost of materials and installation.

Setting increasingly well developed standards for waterproofing materials and installation methods contribute to improving the overall quality of these systems. With this paper, the authors seek to advance efforts to improve standards for waterproofing materials.