Unlike residential roofing, commercial roofing generally involves flat roofing systems, because they cover a much larger area than residential roofs typically do. While some types of shingle roofing systems are prevalent for residential roofs, it’s not generally advisable for commercial roofs, for a couple of reasons. When shingles are installed on a flat roof, water can easily become trapped under the shingles, even if they’re properly installed, and when that happens, there’s no place for the water to go. The water will then remain in place and weaken the shingle, and eventually the roof itself. Most flat roofs will stay leak-free for approximately seven years, and shingled flat roofs will not be leak-free for even that length of time.
For this reason, most cities have requirements for the degree of pitch to a shingled roof. The pitch of a flat roof can either be structurally existing or may require the construction of a specially designed taper system. Rather than take a chance on a shingled commercial roof, you’re much better off to install either a thermoplastic polyolefin (TPO) roof system, or an ethylene propylene diene monomer (EPDM) system, which consists of synthetic rubber. In this discussion, we’ll consider the differences between these two popular commercial roofing systems.
TPO Roofing Systems
Although EPDM roofing systems have been the industry leader for more than half a century now for single-ply roofing, TPO is rapidly gaining in popularity on EPDM, and may even overtake it as the preferred industry choice in the near future. There are many advantages offered by TPO which make it so popular for commercial roofing, starting with its energy efficiency. EPDM has a dark surface, which in summer conditions will absorb heat, forcing cooling systems to work overtime, whereas TPO roofing reflects sunlight, allowing commercial air conditioners to work more efficiently.
TPO also has a somewhat higher resistance to punctures than EPDM. It offers roughly three times more protection against punctures, which translate to leaks when the rain starts coming down. When being installed, TPO roofing systems are always welded, making the system extremely durable, but on the contrary, can also complicate installation because welding requires an electrical source. For this same reason, any repairs which might become necessary for a TPO system are harder to implement because electricity will be required to do the repair work.
See examples in our TPO Roofing Photo Gallery
EPDM Roofing Systems
If your commercial building is located in an area which typically receives a significant number of hail storms, EPDM is the way to go. Its synthetic rubber surface will essentially bounce the hail off with little to no damage to the roof surface or system. TPO systems, on the other hand, are made of thermoplastic, and when struck by hailstones will produce concentric circles that remain in place, and may compromise the membrane of the roofing system.
As mentioned above, when it’s necessary to conduct repairs on an EPDM roofing system, it’s somewhat easier for roofing specialists to implement them because no electrical source is needed for welding. Also, if your commercial building has solar panels installed or if you’re thinking about having them installed, you’d be better off choosing EPDM because it won’t interfere with the absorption of sunlight. TPO systems reflect sunlight back off the surface and into the solar panels, which might well cause them to fail during operation.
See examples in our EPDM Roofing Photo Gallery
TPO vs. EPDM Comparison Table
|Historical Usage||20 years||60 years|
|Sunlight||Reflects sunlight||Retains heat from sunlight|
|Attachment||Chemically adhered||Mechanically fastened|
|Fusion||Seams fused with hot-air gun||Seams fused with seam tape|
|Color Options||White, grey, tan, others||Black|
|Duration||15-20 years||25-30 years|
If You’re Still Undecided
Both of these roofing systems are excellent at protecting your commercial building and the contents inside your home. Choosing one over the other may depend on your geographic location, taking into account heat, hail, and rain, or it may depend on external factors, such as your intent to mount solar panels on the roof. Both of these systems can be mechanically-fastened, which is advantageous in cold weather installation. Both also have the ability to be fully-adhered systems, which is the best approach for the sake of durability and warranty usage. If you can’t quite make up your mind on which system would be better for your commercial building, please contact HomeGuard Roofing & Restoration with any questions or concerns. We’ll be happy to provide you with an expert recommendation on the best roofing system for your circumstances.