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Definition of Roof Waterproofing

Today, there are many materials available to choose from, for roof waterproofing. In the past several years liquid applied membranes proved to be a feasible, economical and more environmentally friendly solution. When searching throughout various roof "coatings", as these materials are commonly called, roofing contractors realize that not all are created equal. There are a few general categories of liquid applied membranes for roofing, each of these categories including large varieties of products to choose from.

Steps to waterproof a roof

A typical application of liquid applied roof membranes consists five main steps, which should all be treated with utmost importance, following the product manufacturer instructions. These steps are: cleaning, priming, treatment of details, main coating application, and inspection.
  • The first step in waterproofing a roof is cleaning of the substrate. All successful liquid applied membrane applications require superior adhesion. Because of this reason, proper cleaning is just as important as the actual correct application of the liquid material. Typically, pressure washing is the most common method for cleaning the substrate surface. This process eliminates the so-called bond breakers. Additionally, this will expose details needing treatment, that may not be visible at a first glance.
  • Following cleaning, priming of the surface is designed to improve the adhesion of the membrane. Primers also aid to block bleeding of the bituminous oils from the existing roof through the liquid membrane. Before the application of most primers, the contractors must ensure the surface is dry. To reduce drying time contractors generally use air blower or torches.
  • The third step is the treatment of details. Contractors must carefully treat all details and only after this step is completed, should they resume the field application of the liquid membrane. Details such as interior and exterior corners, as well as wall to floor type corners, metal flashing terminations and penetrations such as pipes, vents, drains, etc. are typically pre-treated with reinforcing fabric embedded into the liquid membrane and/or with a flashing grade sealant.
  • Next step is the application of the liquid membrane onto the roof. There are two kinds of applications of liquid applied membranes; some require the impregnation of reinforcing mat during installation and some do not. Regardless if the fabric mat is mandatory or not, most of the manufactures require the coating application to be performed in two or more successive layers. The consumption rate of each coating product is stated in the manufacturers technical specifications. Method of application, substrate porosity, temperature, and waste are external factors that may influence the specified consumption rate.