PVC vs TPO Membrane Roofing Systems
TPO and PVC have a lot in common. Both construction specialties are heat weldable roof systems that are typically white in color and have been around for a while. Their specifications are also similar and both roof systems come with warranties varying from 15 – 30 years in length. The cost to extend these warranties further is very minimal and should be considered. Note that both roofing systems need to be inspected and certified by the supplier for the warranty to be valid. Don’t find yourself down the road without the certification.
Other variables—45 mil or 60 mil in thickness? The 45 mil roof will have a 10 to 15 warranty. The 60 mil roof system will have a 15 to 20 year warranty and will be more hail resistant. Warranties can be extended in two ways: Material Only Warranty Extensions or Material and Labor Warranty Extensions. Either are shockingly inexpensive. Pennies on the dollar.
Remember this important step in the process: For a Warranty to put in place the Roof Membrane Manufacturer will send a Roofing Inspector to inspect and certify the roof BEFORE issuing the warranty.
Polyvinyl Chloride, PVC, is known for being one of the original single-ply roof systems and is typically a rigid product. It was first introduced to the United States in the 1970s and initially had a bad track record. Think of a PVC pipe or PVC trim on a house: that is PVC in its natural state. However, in order to make PVC flexible, plasticizers are added to the membrane. Problems can occur from the addition of these plasticizers when they leach out of the membrane in a process called “plasticizer migration.” This causes the PVC membrane to shrink, shatter and crack over time. In fact, some of the first-generation PVC roof systems, which were not reinforced, would completely shatter like glass.
Today, modern PVC roof systems manufactured by reputable companies have greatly reduced the problem of plasticizer migration. In many cases, this problem has been reduced from entire roofs failing to just minor cracking and shrinking after decades of use. Some PVC manufacturers have even substituted typical plasticizers for KEE: an alternative ingredient used for thermoplastic processing which does not have the same plasticizer migration problem. However, KEE membranes are slightly more than standard PVC membranes making them a little more expensive than TPO membranes.
When it comes to chemical resistance, PVC maintains an edge over TPO. PVC is the best single ply product available on roofs with heavy grease, oil, and ponding water because it is not as easily worn down. Some PVC manufacturers even warranty their products against these problems when all other roof systems, including TPO and EPDM, have specific exclusions against these items.
In contrast, thermoplastic polyolefin, TPO, is known for being one of the newer products in the roofing industry. It was first introduced to the United States in the mid-1980s and quickly built traction as a less expensive alternative to PVC. It has similar resistance to chemicals such as greases and oils like PVC, however, PVC maintains an advantage. On the other hand, TPO is a little less expensive than PVC and is known to have a similar lifecycle and warranty.
One of the biggest advantages to TPO over PVC is that TPO does not have a problem with plasticizer migration. As a result, TPO does not shrink, shatter or crack over time.
In summary of these construction specialties PVC is the best product suited for Hospitality projects where as TPO can be used on Professional/Retail projects for a cost savings.