April 20, 2021

The Importance of Waterproofing Your Concrete Structure

You spent millions of dollars constructing a new parking garage, built balconies off a new condominium, and/or put in a new pool for hotel guests to enjoy, but you are still deciding whether to spend the extra money on a deck coating system to waterproofing the concrete. We say, spend the money. According to The Constructor, by definition, “waterproofing is the formation of an impervious barrier over surfaces of foundations, roofs, walls, and other structural members to prevent water penetrations which results in building surfaces are made water-resistant and sometimes waterproof.” It is crucial for property managers and construction professionals to understand that preventing water and chloride infiltration is vital to the longevity of your structure. Ultimately, we suggest utilizing a deck coating system and regular maintenance to help protect and even extend the life of the concrete. For this week’s blog post, we discuss why deck coatings are needed to protect your concrete surface and provide some deck coating recommendations as well.

What are Deck Coatings?

Before we dive into why a deck coating is necessary for protection, we need to define what a deck coating is. Deck Coatings consist of multiple layers of fluid applied compounds that cure to a tough elastomeric, resilient, waterproofing coating. When properly designed and formulated, these coatings make up engineered systems that prevent water from entering the surface to which they are applied while providing a safe (nonslip) surface with pleasing aesthetics. These systems are elastomeric and will span structural or shrinkage cracks that manifest in the concrete. The base coat must adhere tenaciously to the substrate preventing the migration of water in the event of physical damage to the coating. Each component of the system must likewise have excellent adhesion to each other so each component can work as one while providing individual properties to enhance the system. The system must have a topcoat with a high tensile strength to withstand the rigors of pedestrian or vehicular traffic.

Why are Deck Coatings Necessary?

According to Building Enclosure online, “waterproofing is required at concrete structures to keep moisture out of the facility and to protect the structural components of concrete.” Deck coatings protect the surfaces to which that are applied as well as the area below these surfaces from the affects of water penetration.

Water penetrates concrete through open pores in the concrete left when the water used in the making of the concrete evaporates. Water also penetrates concrete through shrinkage or structural cracks in the concrete. In freeze-thaw areas, the water that enters the concrete freezes as it very slowly passes through. As you know, when water freezes it expands, exerting a lot of pressure from within the concrete. This outward pressure eventually causes the concrete to break away. A condition known as “spalling.” Spalled concrete allows even more water to enter the concrete, resulting in more spalling and ultimately total deterioration of the concrete. Concrete decks contain steel reinforcing bars to give strength to the concrete. Many balconies on high rise building are cantilever. These decks depend entirely on the steel to hold them up. Water enters the concrete via cracks; it causes the re-bars to oxidize (rust). Like frozen water, the oxidation grows and puts a great outward pressure on the concrete, resulting in the concrete breaking (spalling). The steel re-bars which are vitally important to the structural integrity of the concrete deck eventually deteriorates, jeopardizing the very existence of the balcony. In coastal areas where salt is continually present, the airborne chloride ion (salt) is on the deck surfaces and carried into the concrete with rainwater. The salt enhances the deterioration process of the steel re-bar. Inland areas are not spared from the effects of salt as in the northern climates; salt is used on the roads to remove ice. This road salt is carried into parking garages along with accumulated ice. As the ice melts, it carries the salt into the cracks in the concrete.

Areas below the surface include occupied space beneath a plaza deck, walkway, balcony, recreation deck, terrace, and other areas subject to pedestrian traffic. Water entering these areas from the deck above will cause unsightly and perhaps very costly damage. (ie: Stained ceilings, damage to furniture, carpets, paintings, etc.) Water in electrical fixtures can cause loss of power or fire.

On decks subject to vehicular traffic, there are typically parking decks below the top parking deck. Water penetrating a parking deck with automobiles parked below can cause serious damage the paint finish (ie: As the water goes through the concrete it collects efflorescence from within the concrete. This is a lime product that can cause damage to surfaces it comes in contact with). Quite often, there are retail stores or storage areas under a parking deck. In these areas, the parking deck is the roof of the store or storage areas. As a roof, it must be waterproof while supporting vehicular traffic. A tough, elastomeric, water-proofing deck coating is the answer.

Deck Coating Recommendations

Pecora’s Pecora-Deck traffic coatings prevent the degradation that occurs when water infiltrates traffic bearing surfaces all while maintaining an attractive architectural appearance. Pecora offers four different systems used in various applications: vehicular, pedestrian, high-build, and re-coat. These systems also reduce concrete deterioration from freeze-thaw damage, chloride-induced corrosion, and cement paste deterioration. We recommended using our Pecora-Deck 800 and/or HB1000 Series components which can be applied interchangeably depending on the necessary requirements for your project. As stated above, preventing water and chloride infiltration is vital to the longevity of your structure. Utilize the full line of Pecora traffic coatings to protect and extend the life of concrete.

For more information, or the right deck coating application recommendations for your project, we urge you to contact our Pecora Corporation Technical Services Group. Our expert team is highly qualified to recommend the proper solution and perform testing between Pecora’s products and jobsite samples. Our Technical Services staff offers training in product technology and use, provides the technical assistance you require in the planning and implementation of your project. They can be reached by email or by phone (800)-523-6688.



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