{"id":6011,"date":"2014-11-26T14:22:40","date_gmt":"2014-11-26T19:22:40","guid":{"rendered":"http:\/\/www.constructionspecifier.com\/?p=6011"},"modified":"2017-01-12T14:34:32","modified_gmt":"2017-01-12T19:34:32","slug":"an-overview-of-waterproofing-solutions","status":"publish","type":"post","link":"https:\/\/www.constructionspecifier.com\/an-overview-of-waterproofing-solutions\/","title":{"rendered":"An overview of waterproofing solutions"},"content":{"rendered":"
\"HoffArch01\"<\/a>
All photos courtesy Hoffman Architects<\/figcaption><\/figure>\n

by Richard P. Kadlubowski, AIA
\n<\/strong>Waterproofing failures are more easily overlooked than roofing problems, so design professionals tend to hear less about them. When compared with a reroofing project, however, a below-grade or interior rehabilitation can be far more disruptive and expensive.<\/p>\n

Whereas a roof leak can generally be identified with simple test probes, waterproofing breaches can be challenging to diagnose. Even a seemingly superficial leak can be symptomatic of hidden moisture-related deterioration. For basements, vaults, tunnels, and water features, excavation of overburden is often necessary; in commercial kitchens or lobbies, removal and replacement of fixtures and finishes is frequent.<\/p>\n

In most commercial and institutional applications, a complete reroofing project can usually be anticipated every 20 years or so. Waterproofing, because it is so difficult to access, should have a design life as long as that of the building\u2014unfortunately, with so many opportunities for damage, incorrect design, or poor execution, it can fail well before its time. When this happens, architectural investigation is needed to determine the location and cause of the leak, the extent of the damage, and the appropriate remedy.<\/p>\n

While it can be a major undertaking to properly identify and correct faulty waterproofing, it is far worse to adopt a patch-it-and-hope-for-the-best attitude. All too often, even well-meaning attempts at treating the symptoms of waterproofing failure serve only to trap or redirect moisture, compounding the problem. While prevention is the obvious first choice for waterproofing success, there are many occasions for error: in design, during construction, and throughout operation. Until the waterproofing deficiency is resolved, the problem will only get worse.<\/p>\n

Waterproofing basics
\n<\/strong>Various components contribute to a waterproofing system, such as drainage composites that direct water away from the structure, tie-ins between fa\u00e7ade and foundation membranes, and watertight plumbing in food service areas.<\/p>\n

Impervious membranes are one critical component of waterproofing, both for below-grade applications (e.g.<\/em> foundation walls, basements, tunnels, and vaults) and areas subject to high moisture levels (e.g.<\/em> fountains, lobbies, kitchens, and mechanical rooms). Waterproofing membranes may be applied on the \u2018positive\u2019 or \u2018negative\u2019 side.<\/p>\n

Waterproofing on a building is typically an impervious material that will prevent water entry; building cladding materials may or may not be actual waterproofing. Most building cladding materials (e.g.<\/em> brick masonry in a cavity wall assembly or rainscreen systems) are not waterproofing\u2014they are only weather barriers. Similarly, although Tyvek-type materials shed water, they are not true waterproofing.<\/p>\n

There is a distinction between waterproofing and roofing that has to be understood. Plaza decks over occupied spaces are waterproofed; the deck is technically not a roof. The manufacturers will make this distinction, because also typically waterproofing applications do not come with as complete a warranty coverage as do some roofing systems.<\/p>\n

Positive-side waterproofing
\n<\/em>By creating a waterproof barrier on the side of applied hydrostatic pressure, positive-side waterproofing prevents water from entering the wall. For a foundation, this would be the outside surface, closest to the soil; for a fountain, it would be the inside (i.e.<\/em> where the water is).<\/p>\n

For below-grade applications, the earth can be banked back such that a positive-side membrane is installed after the foundation is set. In urban areas, this may not be an option. Blind-side waterproofing incorporates the waterproof membrane on the face of the shoring before the foundation is cast. Concrete is then poured, and the waterproofing fuses to the foundation wall as it cures.<\/p>\n

Options for positive side systems include:<\/p>\n