When reading various product literature, I often run across the words "waterproofing" and "dampproofing." They seem to be used interchangeably. Is there a difference? If so, which products are waterproofing products and which are dampproofing? For what applications are each needed?
According to ACI 515.1, waterproofing is a treatment of a surface or structure to prevent the passage of water under hydrostatic pressure. Dampproofing is a treatment of a surface or structure to resist the passage of water in the absence of hydrostatic pressure. As a guideline, waterproofing is often needed for below-grade applications, whereas dampproofing is often satisfactory for above-grade applications. Traditionally, waterproofing barriers consist of multiple layers of sheet-applied materials impregnated with asphaltic, bituminous, or coal tar material. Today, a number of other waterproofing barriers can be selected, which include cold-applied systems such as elastomeric membrane barriers, cementitious membranes, modified bituminous materials, bentonite-based materials, and a number of proprietary types of waterproofing barriers. The number of coats or plies, thickness, and types of materials will vary with job conditions. Dampproofing materials include most sealers, paints and coatings, and water-repellent admixtures and cements. However, their effectiveness varies depending on the material and the application thickness or dosage rate. There is, of course, a lot of gray area. When determining a system's ability to repel water, it is probably best to view the products on a continuous scale rather than attempting to define them as either waterproofing or dampproofing materials.