WSRCA Seven-Year Report on the TPO Weathering Farm Project

September 13, 2010

The Western States Roofing Contractors Association (WSRCA) published the Seven-Year Report for the TPO Weathering Farm Project in the May/June 2010 issue of Western Roofing. A copy of the report is on the Firestone website.

Firestone is one of the four TPO manufacturers involved in this project that started in 2000, with installations occurring in 2001/2002. Membrane from each manufacturer — Firestone Building Products, Carlisle Syntec Inc., Dow Roofing Systems (formerly Stevens), and GenFlex Roofing Systems – was installed at each site.

  • Las Vegas, NV – generally hot and dry
  • San Antonio, TX – generally hot and humid
  • Seattle, WA – generally moderate with wet and dry periods
  • Anchorage, AK – generally cold and damp

Earlier reports were issued after 3 and 5 years of aging. At 7 years, detailed field observations were documented and samples were sent to an independent laboratory for testing all four membranes at each site.

Field observations focused on: Laboratory testing included:
• Seam integrity • Color and hue • Overall thickness • Breaking strength
• Walk pads • Solar reflectivity • Water absorption • Elongation at break
• Chalking • Sealing of cut edges • Dimensional stability • Glass transition temperature
• Surface characteristic • Effect of hard creases • Thickness over scrim

Overall, the seven-year report is certainly positive. All of the field observations and laboratory tests show that Firestone UltraPly TPO is performing very well over time. Moreover, UltraPly TPO is the only TPO membrane that has not changed its formulation since these roofs were installed
Key points and observations reported include:

  • “After seven years of service, the membranes at all Roof Areas appear to be weathering quite well on the four WSRCA TPO Weathering Farm test sites. This suggests that when TPO roofing is considered for a project, that white, 60 mil TPO membranes are a reasonable alternative to other single-ply roof membrane systems.”
  • “In general, all seams are performing well.”
  • “The welding of the patches for the test cuts show[s] that after seven years of aging, these membranes can still be effectively welded to.”
  • “All roofs are presently leak-free and these 60-mil white TPO membranes are so far showing good in-service performance.”
  • “WSRCA welcomes others to conduct similar full-scale roofing and waterproofing research. It should be noted that, to the best of our knowledge, no other roofing material has undergone such an independent, thorough, and long-term full-scale study as WSRCA has diligently conducted here with TPO.”
  • A contractor “reported that many roofs in the area had been badly damaged by hail, and was surprised to see this TPO roof undamaged.”


Once again, here is more evidence that with Firestone UltraPly TPO, Nobody Covers You Better.
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Additional Resources

WSRCA Seven-year Report on the TPO Weathing Farm Project

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