Different types of flat roofing systems
A flat roof and a sloped roof have different types of materials because the water can not run off a flat roof as efficiently as it can a sloped roof. There are a lot of different choices of materials to use when it comes to a flat roofing system. Flat roofs are convenient for installing large HVAC equipment. It can be used as a roof top garden, deck or patio.
Asphalt roll roofing
Asphalt roll roofing usually consists of one layer of asphalt-saturated organic or fiberglass base felts, which is applied over roof felt with nails and cold asphalt cement, and is usually covered with a granular mineral surface. Seams are typically covered with a roofing compound. The life exceptancy of roll asphalt is about 10 years.
EPDM (Ethylene Propylene Diene Monomer) roofs are single-ply membranes (one ply of roofing material, not multiple plies laminated together). EPDM is a rubber material whose main components consist of the compounds ethylene and propylene. It is relatively inexpensive, simple to install, no odors /fumes, and fairly clean to work with when compared to conventional built-up roofs.The three standard application procedures are fully-adhered, mechanically-fastened or loose-laid. The life expectancy is 12-25 years (depending on environmental conditions).
Modified Bitumen is asphalt that has had modifiers, such as polymers, that are added to the bitumen to alter some of its properties for greater stability and flexibility in a wide range of temperatures. It gives it plastic or rubber-like properties. There are two application procedures; torch applied using flame heat to weld the cap sheet to the base sheets or self adhering. The life expectancy is 10-25 years.
PVC (Polyvinyl Chloride) is a single-ply roofing membrane. The different manufacturers of PVC membrane have their own slightly different recipe for its PVC product. Since PVC in its natural state is rigid, it is made flexible with the use of plasticizer chemicals. PVC roofing systems reflect nearly 90% of the heat of the sun, which substanially lowers energy costs. The life expectancy is 30+ years.
TPO (thermoplastic polyolefin) is a single-ply roof membrane. The top ply contains cool roof pigments, UV stabilizers, and other components and the bottom ply contains TPO ingredients to provide consistent weld of top and bottom plies and fillers. TPO roof systems are under continuing development by different manufacturers, so the formulation is constantly changing. So matching TPO, even through the same manufacturer, is hard. TPO has excellent resistance to ozone, is algae-resistant, environmentally friendly, safe to install, highly resistant to tears, impacts, and punctures, and is flexibile to allow for building movement. TPO membranes are installed fully-adhered, mechanically-attached or ballasted. The life expectancy is 7 to 20 years.