Roofing Membranes, System Types & Coatings
TPO short for Thermoplastic Polyolefin consists of a polymer base, polyester-reinforced fabric center scrim, and a thermoplastic oolyolefin compounded top ply. One of the fastest growing roofing systems around, white thermoplastic membrane offers reduced cooling costs and energy savings for facilities located in warm climates. A TPO membrane's reflective surface exceeds the EPA's Energy Star requirements and its white, tan and gray color options are listed with the Cool Roof Rating Council. This means that having a TPO roof on your building will keep the interior more comfortable on hot summer days while reducing your air conditioning bill. TPO is an ideal commercial roofing system that offers superior resistance to punctures and tears, algae growth, UV damage, the elements, and chemical exposure
PVC short for polyvinyl chloride consists two layers of PVC roof material with polyester added in between the layers to act as a reinforcement. Additives are added to the PVC membrane to make the material more flexible, UV stable, and prevent curing. Although white is a common color since it reflects the sun’s heat, different colors are available. PVC membrane is Energy Star and LEED compliant, as well as listed with the Cool Roof Rating Council. Reflecting nearly 90% of the sun's heat, PVC lowers energy cost substantially, especially in high-heat areas such as the southeastern United States. PVC roofing membranes offer an impressive set of advantages. Among the most notable benefits are strength, durability, resistance to moisture, wind, fire and chemicals. Also, PVC is Eco-friendly and can be fully recycled after its service life.
EPDM short for Ethylene Propylene Diene Monomer is a synthetic rubber consisting of oil and natural gas. Choices include black or white EPDM, and roof systems include mechanically attached, fully adhered, and ballasted. EPDM membrane is highly resistant to UV rays, high winds, hail, and extreme hot and cold temperatures. Due to EPDM'S elastic characteristic it is able to withstand structural expansion and contraction. EPDM has been installed on roofs since the mid 1970's and has an excellent track record supported by actual field installations and various laboratory studies.
Modified Bitumen Membrane
Modified bitumen or “mod bit” is mainly made up of asphalt modified with atactic polypropylene (APP), styrene butadiene styrene (SBS), synthetic rubber or other ingredients that enhance the physical properties of the asphalt. SBS and APP are the most common bitumen modifiers. Modified Bitumen Roof System are typically installed with 1-3 ply’s, and come in many different colors. There are several ways to install a modified bitumen roof, but the four most common methods are self adhered, cold applied, heat weld, and torch down. Modified Bitumen is very resistant to physical damage, and has a high fire, wind, and hail damage rating. Modified Bitumen was developed in Europe in the 1970s and the United States started developing modified bitumen compounds in the late 1970s and early 1980s.
The most important factors of any roof coating application is proper preparation of the roof and following installation details. Roof coatings are made to protect and extend the service life of existing roof systems such as single-ply, modified bitumen, metal, and built up roof systems (BUR). Coatings protect roof membranes from ultraviolet rays, general weathering, and provide a watertight layer on an existing roof. Roof coatings are thicker than standard paint, have a higher solids content, and often applied in several coatings with a sprayer, roller, or brush. Most roof coatings are extremely elastic due to the high-quality resins that are introduced during manufacturing allowing the coating to expand and contract with swings in temperature. Coatings can enhance reflectivity, and lessen a building’s cooling load. Many flat roofs puddle or pond in some areas. Most roof coatings are not covered under manufacturers warranties for ponding water, and can fail pre-maturely if installed in areas that tend to have standing water.
Serious consideration should be given the coating being selected. A few manufacturers will warranty their coatings to included ponding water. Most manufacturers for acrylic roof coatings will not warranty roofs for ponding water, however some silicone and polyurethane roof coatings manufacturers will. There are several manufacturers and types of roof coatings some better than others. The most common types of roof coatings are acrylic, silicone, polyurethane, and asphalt.