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From roof to foundation

Waterproofing methods and technologies continue to advance. Working with a knowledgeable consultant can help determine the best assemblies for a project.
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Consulting experts when selecting appropriate waterproofing

by Carter Pogue

Severe weather can cause extensive damage to a building’s roof, foundation, and interiors. Waterproofing plays an extremely important role in protecting every aspect of a structure’s construction. Knowing which coverage to specify for a particular project is more than just a science—it is an art form. Consulting with an experienced specialty contractor for the best waterproofing options available will ensure a quality job to extend the structure’s life.

Water is moved through a building via numerous forces, including hydrostatic pressure, capillary action, wind/air currents, surface tension, and natural gravity. If there is any breach in a structure’s envelope, water is sure to find its way in.

Waterproofing has come a long way since 1915, when ironite was first introduced. Painted onto the inside of basement walls, this material became a popular option because it could be applied quickly and was less expensive than the traditional dampproofing methods at the time.

As the decades progressed, so did improvements in the materials and techniques used to completely waterproof a building—from the roof to its below-grade exterior and interior walls and everything in between.

Above-grade walls
The exterior walls of a building can be a significant source of unwanted water leakage. Many openings are required in commercial building walls—from plumbing and irrigation connections to lighting, HVAC system elements, exhaust vents, air intakes, joints around windows and doors, and fire alarms. There are also unplanned holes caused by aging brick joints that need re-pointing, vanishing sealants, damage from acid rain, and settling cracks. All wall penetrations provide easy access for water, bugs, rodents, or birds to enter the building and cause damage.

A structure’s first line of defense against the elements is above-grade waterproofing, which includes caulks and sealants to seal the perimeters of windows and other openings. The amount of sealant needed on a new or existing structure depends on exposure and expansion/contraction problems that may be identified. Some types of sealants include:

  • elastomeric breathable wall coating systems;
  • protective/decorative surface coatings; and
  • clear water repellents.

Concrete, terrace areas, and decks
In the winter, freeze-thaw cycles can cause big problems with concrete structures. When water infiltrates concrete, it can freeze and then occupy nine percent more volume than in its liquid state. This expansion causes distress on the concrete, which can lead to fractures that continue to grow exponentially as saturation of the material increases.

A wide range of restoration, repair, and reinforcing services are offered by certified, specialty contractors who can repair cracks, spalls, rust spots, deterioration, pot-holes, and heaves in concrete and masonry. More often than not, concrete repairs are made before they become a more serious or costly issue, but there are also measures that can actually prevent future damage.

Applying hot-applied or below-grade waterproofing to buried structures, urethane waterproof traffic coatings to parking decks, and protective acrylic coatings to pedestrian areas and exterior façades extends the life of the repair, protects adjacent areas still in good condition, and significantly improves the aesthetics of the area treated. Used over concrete, wood, or steel, a variety of deck coatings can prevent leaks from penetrating to areas below and maintain the surface’s color to keep it looking like new. Recent technology has provided materials for these special coatings suitable for suspended slabs, recreational roof decks, garages, patios, balconies, sun decks, areas around pools, and other locations requiring a durable surface.

Roofs
A commitment to good roof maintenance practices can prevent overflowing gutters, clogged downspouts, and excessive ponding water, which can lead to costly roof, façade, and foundation damage. Decaying leaves, pine needles, and dirt runoff can all be contributors, which is why it is essential all roof drains remain clear of obstructions. In addition to the risk of water pouring into tenant spaces should a breach in the roof occur, the freezing and thawing of ponding water during the fall and winter can cause extensive roof damage.

Applying waterproofing to a structure’s roof is important and requires a professional’s expertise to determine which option works the best. Some available roofing systems include:

  • synthetic rubber materials;
  • hot rubberized asphalt; and
  • insulated roofing membrane systems.

Feasibility of installation, cost, and compatibility play major roles in deciding which roofing assembly is best-suited for a structure.

Below-grade systems
A number of excellent below-grade exterior foundation waterproofing systems have become available within the last 20 years to prevent water penetration through basement walls, concrete lids, pits, and other below-ground areas. These waterproofing materials may be applied on the inside or outside of the wall or foundation.

Major examples include:

  • fluid-applied elastomeric membranes, mastics, and coatings that form a tough, seamless membrane to withstand abuse and high levels of hydrostatic pressure;
  • hot-applied rubberized asphalt for horizontal waterproofing in split-slab construction and insulated roof membrane assembly roofs;
  • single-ply sheet systems (e.g. rubberized asphalt sheets, ethylene propylene diene monomer [EPDM] synthetic rubber, polyvinyl chloride [PVC], chlorinated or chlorosulfonated polyethylene [CPE or CSPE], butyl rubber, and neoprene); and
  • bentonite clay panel and sheet systems that swell when they become saturated to block moisture from entering a building.

Interior systems
Metallic, capillary/crystalline, and cementitious materials are available for waterproofing a structure’s interior. These materials may be applied by brush, trowel, spray, or dry-shake methods to concrete or masonry substrates opposite the source of moisture. For foundations, these materials are applied to the interior of the structure. For tanks, reservoirs, and other structures that hold water, these materials are applied to the exterior.

Conclusion
Waterproofing should never be limited to one option or a go-to method. Selecting the most suitable strategy should be researched through consultants, engineers, and material manufacturers. Installers should be experienced and comfortable with the products they are installing. Surface preparation is critical for all surfaces and with all products.

It is also important to remember there is simply no maintenance-free structure or material. Maintenance programs recommended by the manufacturer should be stringently followed to stay in accordance with warranty obligations.

Carter Pogue is a project manager with Western Specialty Contractors. He started his career with the firm almost 15 years ago as a general cement mason, learning all aspects of the restoration/waterproofing business. Pogue quickly moved into a general foreman role in 2004, facilitating projects such as the University of Missouri−Columbia stadium restoration before being promoted to general superintendent where he coordinated and executed multiple construction projects and subcontractor operations. In 2012, he became a project manager with Western. Pogue is an active member in the local Great Plains Chapter of the International Concrete Repair Institute (ICRI). He has been awarded multiple safety and achievement awards within the company and is certified through the Post-Tension Institution (PTI). Pogue can be reached at carterp@westernspecialtycontractors.com.

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