Cold fluid-applied PMMA waterproofing

Cold fluid-applied polymethyl methacrylate (PMMA) waterproofing systems are comprised of several products that together create a water-resistant barrier most commonly used in horizontal applications such as on balconies, terraces, parking structures, and roofs. Because it is liquid-applied and can adhere to a variety of substrates including existing roof membranes, it is also used as flashing or in combination with other water barrier systems. It may be covered by other materials or left exposed. PMMA waterproofing systems have many potential combinations of components depending on the intended use of the area, but commonly include a catalyst, primer, liquid resin or membrane, reinforcing polyester fleece, and a finish or coating. Additional layers not covered in this CP include decorative, textured, or colored layers that may contain sand, aggregates, and/or a variety of pigments. The primer, resin, and finish are most often two-part PMMA-based products that require the addition of the peroxide catalyst immediately before application to initiate curing and are applied with a roller or brush. Generally, a substate is primed then coated with two thirds of the resin. The polyester reinforcement fleece is rolled out while the resin is still wet, then an additional third of the resin is applied atop the fleece. Some systems are sealed with a finish or top coat before use. Systems cure relatively quickly and may be trafficable in as little as 60 minutes. Chemical components are temperature sensitive resulting in products that cannot usually be applied much below freezing and should not be stored in direct sunlight or at high temperatures for risk of ignition or combustion.