Not all flat roofs are the same. When it comes time for a full roof replacement on your flat-roofed commercial building, you have choices in the type of roofing material. Making the correct choice depends on a variety of factors, so it is best to have a basic understanding of all of the roofing options that are available.
Built up roofing (BUR) membranes are your most cost effective option when it comes to a new flat roof. This style of roof is built up in layers. First, a membrane is laid down and then it is covered with bitumen, a type of roofing tar. These layers are repeated until the final top coating of gravel is installed. BUR roofs are relatively resistant to damage and they can also be easily patched as they age. BUR roofs can be heavy, so your building roofing supports must be designed to hold the extra weight. With regular maintenance, a BUR roof is an economical and long-lived option for your commercial roof.
Modified bitumen roofs consist of two layers each of roofing fabric and bitumen, as thin bitumen sheets are adhered to the fabric membranes. Modified bitumen roofs are lighter weight than BUR membranes, but they share the traits of a long life and durability. Modified bitumen roofs can be a bit more expensive than a BUR roof, but they are also lighter weight and are suitable for more structures. Modified bitumen can also be walked upon with no damage, making it a good choice for roofs with foot traffic.
Thermoplastic membranes are also referred to as TPO or PVC membranes, depending on the exact composition of thermoplastic used. These lightweight roofs are suitable for most roofs. They are also highly reflective, which can help prevent your building from becoming a heat sink. This can save on energy costs, particularly in warm climates. Thermoplastic is often used on restaurant roofs, since it won't break down when exposed to oil or grease from a ventilation system due to its chemical resistance. Thermoplastic membranes do require annual inspections, as any damage must be patched immediately to avoid further issues.
Rubber roofing, also called EPDM roofing, works well in areas with extreme cold or extreme temperature fluctuations, since the rubber won't be damaged by expansion and contraction forces. EPDM is resistant to UV light damage as well, which can help prolong roof life in areas with high light exposure. Unfortunately, it is not as chemical-resistant as a thermoplastic membrane, so it is not suitable for some applications.
Contact a commercial roofer, like those at National Roofing Corporation, or someone in your area to learn more about these and other options.