Application of Waterproofing in Building Construction
Two fundamental ways of categorizing waterproofing systems are in terms of their position relative to the structure and by the sequence of installation of waterproofing and structural elements.
Positive-Side Application—Positive-side applications are on the side of an assembly that is intended to be exposed to moisture. Positive-side applications include waterproofing installed at the top of the structural decks of plazas and as the lining of planters. Waterproofing may be installed on the positive-side of below-grade walls when an excavation on the exterior side of the wall allows access for safe waterproofing application.
Manuscript received May 23, 2005; accepted for publication August 29, 2005; published online February 2006. Presented at ASTM Symposium on Durability of Building and Construction Sealants and Adhesives, Second Symposium on 15-16 June 2005 in Reno, NV; A. T. Wolf, Guest Editor.
1 Consultant, Wiss, Janney, Elstner Associates. Inc., 2200 Powell Street, Suite 925. Emeryville, CA 94608.
2 Associate III, Wiss, Janney, Elstner Associates, Inc., 2200 Powell Street, Suite 925, Emeryville, CA 94608.
3 Associate Ш, Wiss, Janney, Elstner Associates, Inc., 2200 Powell Street, Suite 925, Emeryville, CA 94608.
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Positive-Side, Blind Application—This is waterproofing installed on the positive (wet) side prior to construction of the wall or slab. Examples are waterproofing that is installed before slabs-on-ground are poured over it and waterproofing that is attached to below-grade retaining walls before the concrete wall is placed. Methods of placing concrete walls against waterproofing include pneumatic placement (shot – crete) and cast-in-place with one-sided forms.
Negative-Side Application—Negative-side installation takes place on what is intended to be the dry side of a wall or slab. An example is the application of crystalline waterproofing slurry on the interior surface of the wall. Another approach to negative-side waterproofing is injection of waterproofing from the interior (dry) side of the wall. Holes are drilled into or through a concrete below-grade wall or slab and waterproofing grout is injected into cracks or through the concrete and into the soil.
Integral Waterproofing—Concrete is sometimes designed to retain water on its own, either without a waterproofing membrane or as a secondary line of protection against water intrusion. Water-stops are installed in concrete cold-joints. The concrete may be designed for minimal porosity and cracking. The integral waterproofing capacity of concrete may be augmented by including waterproofing admixtures in the concrete mix design.
Standards development is needed for all these types of waterproofing; however, the focus of this paper is materials used in building construction for positive-side applications and positive-side blind applications.