Even though there are many different varieties of roofing products on the market, liquid roofing systems own their own specialty in terms of longevity. It is important to note that a liquid-applied roofing membrane or coating can itself be the exterior weathering surface, or it may be coated with another UV and weather stable layer. Liquid-applied roof membranes are constructed in place from a liquid resin and reinforcing material. Depending on resin chemistry, a catalyst or hardener may be added to induce the curing process. In most instances, a primer is required. Liquid applied roof membranes typically are reinforced with polyester fleece or fiberglass mat. Reinforcement typically is set into the resin base coat. The reinforcing material provides the membrane’s crack bridging ability and much of its mechanical strength. Liquid-applied roof membranes may be surfaced with aggregate (e.g., sand, mineral, ceramic granules), sealers.
The liquid material cures to form a monolithic weatherproof membrane. Single-component resin eliminates the need for combining products at the job site. Two component materials require proper mixing at the job site and have a limited pot life after mixing. Liquid-applied roof membranes are more widely known to be used as waterproofing systems but have gained in popularity as roof systems, especially in reroofing situations. However, if a liquid-applied roof membrane does not have reinforcement, it typically is considered a coating system. A liquid roofing product with reinforcement such as fleece or other geotextile material is considered a membrane and if there is no reinforcement it is considered a coating. While reinforcement can be important to a roof system, it is worthwhile to consider the physical properties of liquid-applied roof coatings with and without reinforcement, as the physical properties can help determine what products are best suited to a specific application. Benefits of Fluid-Applied Roof Coatings Fluid-applied roof coatings can be applied as a new roof system on a new roof deck or in a maintenance situation as a re-roofing system over an existing deck.
They have many benefits, but they are most commonly used to prolong the life of an existing roofing system whether it is an EPDM or TPO sheet membrane or another fluid-applied roofing system. These systems contribute to the sustainability of the building structure by extending the life of the existing roof surface and preventing unnecessary roof tear off’s, which contribute a great deal of waste to landfills. If properly maintained, you may never have to tear off the existing roof membrane and a renewable coating can be reapplied every 5 to 15 years. In addition, reflective coatings are often applied over darker colored or aged reflective existing roofs to help reduce energy costs.
Fluid-applied coatings provide a seamless, monolithic surface that is fully adhered so that water cannot migrate beneath the surface. These coatings are lightweight, often less than 1/3 pounds per square foot, are self-flashing, and may qualify for immediate tax advantages based on prevailing tax code in your region related to energy saving building upgrades.
Liquid-applied coatings can be applied over virtually any type of surface, from thermoplastic single-ply membranes such as PVC or thermoplastic polyolefin (TPO), to thermoset single-ply membranes such as ethylene propylene diene terpolymer (EPDM), or chlorosulfonated polyethylene (CSPE-Hypalon). They can also be installed over metal, concrete, built-up roof (BUR), modified bitumen (MB), or spray polyurethane foam (SPF). System selection criteria is probably the most important discussion for a specifier, as there are many different types of liquid-applied roof coatings and choosing the right product for a project deserves careful consideration to avoid problems or premature failures.