TPO Roof Systems
TPO (thermoplastic olefin) became a popular roof membrane in the mid 1980’s. TPO is a thermoplastic which means it can be welded together with hot air; therefore, not requiring seams to be taped or glued. Combined with its lengthening track record, low comparative cost and high reflectivity, TPO has quickly become a favorite of real estate developers, building owners, architects, general contractors and roofers. Also, because of the versatility of the membrane and the multiple application choices available, TPO is a viable product on almost any project. Whether you need to recover an existing built-up roof with fleece-back TPO in hot asphalt, fully adhere TPO to achieve a higher wind uplift rating, or mechanically fasten TPO, this membrane should be considered as an option on your building. Because of these reasons, the use of TPO membrane continues to grow exponentially. TPO membranes are typically white but are available in other colors as well.
Asphalt Roof Systems
Asphalt based roof systems have a long track record of excellent performance. Unlike single-ply roof systems, an asphalt system uses multiple layers of asphalt, held together with felts or modified materials to create a thick, durable waterproofing membrane. These multiple layers make asphalt systems high resistant to punctures. Asphalt systems also have many surfacing options that can increase solar reflectivity and increase the life span of the roof. Surface options widely available today include coatings, gravel and granular surfaced cap sheets.
EPDM Roof Systems
EPDM (ethylene propylene diene terpolymer), by nature, is a black thermoset membrane which can’t be remolded or welded. As a result, seams must be taped or glued as opposed to being welded together like TPO or PVC seams. For years EPDM has been losing market share to competing white single-ply thermoplastic membranes. That does not mean that EPDM does not have a place in the current roofing market. There are many scenarios that EPDM may make sense. As an example, in a re-roof scenario on a building that has existing ballasted EPDM membrane, structural calculations may require the ballast to remain on the building. In that case, replacing the existing EPDM with new EPDM membrane may provide the most durable roof system scenario. Also, reflection from a white single-ply roof may create a problem on a multi-story building with lower roof areas. If a white membrane is used, light may reflect onto the side of the building and into the windows above creating unsightly aesthetics and an uncomfortable atmosphere for employees or owners.
PVC Roof Systems
PVC (polyvinyl choride) roof systems offer many of the same benefits as TPO. PVC is also a thermoplastic which means it can be welded together with hot air; therefore, not requiring seams to be taped or glued. Although PVC is slightly higher in cost than TPO, it is lower in cost compared to asphalt roof systems, and just like TPO, PVC is a highly reflective roof membrane. PVC roof systems offer the same versatility as TPO but PVC is more resistant to certain chemicals. The chemicals in oils, fats and grease may cause a TPO membrane to prematurely deteriorate, while PVC membrane may be more durable in those environments. If your building houses a restaurant, manufacturing plant or some other business that may vent chemicals through the roof, PVC will provide a cost effective option that will perform under the circumstances presented at your property. PVC membranes are typically white but are available in other colors as well.