What is TPO Roofing?
When it’s time to replace the flat roof on your commercial or industrial building, you’ll face a multitude of choices. TPO, EPDM, PVC and modified bitumen lead the field in popular single-ply membranes. Built-up roofing (BUR), commonly known as tar and gravel, still contends for a piece of the pie but continues to drop in favor. Each system offers advantages and disadvantages. Read on to learn why TPO is one of the most popular single-ply choices on the market today.
What is TPO?
Polypropylene and ethylene-propylene rubber polymers bound together create Thermoplastic Polyolefin (TPO). Essentially rubberized plastic, the chemical components sandwich a fiber mesh, known as skrim, to create a tough but pliable membrane. Heat welding bonds the seams so that they become stronger than the TPO in the field. Less susceptible to damage from impacts, tears, gouging or footfall, you can see why many commercial building owners select it. Depending on the membrane thickness and installation method, product manufacturers offer installation warranties ranging between 10 and 35 years.
How is TPO Installed?
Installation comes down to two main methods with variations within each — mechanically attached or fully-adhered.
Mechanically Attached. This method requires no adhesives. Instead, the crew screws metal plates into the insulation and cover board layers at the seam edges before heat welding the seams. As the fastest, most economical method, it also costs the least. But because wind can lift and flutter the cap sheet, possibly drawing conditioned air from the building, it also carries the lowest manufacturer’s warranties and may last a mere 10 to 15 years.
Another mechanical method uses induction heat and specially coated metal plates, set about 30 inches apart. The membrane is heat welded at the coated plates, as well as the seams, to give the wind less opportunity to cause damage.
Fully-Adhered. Fully-adhered simply means glued down. However, for the longest lasting roof and best warranties, full adherence is the only way to go. No screws punch holes in the membrane where water can penetrate the building if a leak occurs. Wind dynamics are foiled by the fact that no airspace remains under the membrane sheet. Although full adhesion works best and lasts the longest, it also costs the most. Any glue worth its name will come at a pretty hefty price, and the method calls for either a larger crew or longer time to install. The payoff, though, is a roof that will last upwards of 40 years or more if well maintained and not damaged.
Benefits of TPO
- Lasts longer than modified bitumen
- Withstands ponding water and foot traffic
- Does not require hot tar kettles and associated risks
- Competitive in price
- Strong seams
- Easy to repair
- Available in white
Disadvantages of TPO
- Stiffer than EPDM and PVC
- Less suitable for roofs with many protrusions and HVAC units
- Unsuitable for restaurants as grease will corrode the material
For more information on commercial roofing options, please give us a call at Rosie’s Roofing and Restoration. We have decades of experience in all types of flat roof systems and are happy to share our knowledge with you. Call us for a free consultation today!