Thermoplastic Olefin (TPO) - Heat Weldable Roofing

May 1st, 2008 — Roofing Products

Thermoplastic Olefin, or TPO, are plastic sheets welded together with hot air creating one continuous sheet membrane. Can be rewelded with the exception of CSPE. Lends itself well to both big box and small roof application because of its hot air weldability.

Thermoplastic Olefin (TPO) - Peel & StickTPO is a single-ply roofing system consisting of a Thermoplastic Polyolefin membrane. The TPO membrane typically comprised of three layers of a TPO polymer base, a strong, polyester-reinforced fabric center (scrim) and a tough thermoplastic polyolefin compounded top ply.


TPO is a trade name that refers to polymer/filler blends usually consisting of some fraction of polypropylene, polyethylene, block copolymer polypropylene, rubber, and a reinforcing filler. Common fillers include, though are not restricted to talc, fiberglass, carbon fiber, wollastonite, and Metal Oxy Sulfate. Common rubbers include ethylene-propylene rubber, EPDM , and others. Currently there is a great variety of commercially available rubbers and BCPP’s. They are produced using regioselective and stereoselective catalysts known as metallocenes. The metallocene catalyst becomes embedded in the polymer and cannot be recovered.

Comparing TPO with EPDM materials, TPO sheets do not form permanent cross-links through vulcanization. Without this cross-linking, thermoplastic roof membranes typically creep or cold-flow under the stress. Most products rely upon internal reinforcement such as woven scrim while others use a non-woven fleece backing material.

Benefits of TPO

In general, TPO membranes are being marketed as a product that combines the properties of EPDM and PVC, without the associated drawbacks that the latter two materials have. In other words, they are supposed to be as UV-resistant and as heat-resistant as EPDM, and as heat-weldable as PVC.

The smooth surface resists dirt pick-up and biological growth compared to other thermoplastic membranes.

TPO membranes usually will carry an Energy Star rating having exceeded guidelines based upon solar reflectance and thermal emittance. Energy Star compliant TPO membranes with their high cool roof ratings help reduce the amount of energy required to maintain cool building environments.

The following benefits and characteristics have been reported for TPO:

  • environmentally friendly and recyclable
  • seams can be heat welded
  • available in many colours
  • resistant to heat and UV degradation
  • resistant to many chemicals
  • good cold-temperature flexibility
  • no external plasticizers added.

Another advantage of TPO, for the Roofing Contractor and Manufacturers anyway, is that there is a shift from some lower priced materials like EPDM to the higher priced TPO materials according to a Principia study. Commercial roofing sales reached $3.3 billion overall in 2007 with single-ply products comprising the largest segment. Single-ply encompasses EPDM, TPO and PVC membranes and accounted for 32% of volume and 28% of value in 2007. However, within the single-ply category, TPO has been taking share from EPDM and PVC.

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This entry was posted on Thursday, May 1st, 2008 at 1:01 pm and is filed under Roofing Products. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.


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2 Comments so far

  1. Mike on May 1, 2008 7:47 pm

    Very informative, great article!

  2. Jack Blankenship on May 24, 2008 7:39 am

    I just received a set of plans calling for a TPO System I have never heard of who is this:(Cooler Manufacturer- Laser Welded TPO?)
    I have searched the NRCA, the Web, I can’t find these guys, next I am calling the architect. Am I in the dark? Does anyone have some info on this company or the system?
    Please notify me.
    Thanks
    Jack Blankenship
    Commercial & Industrial Estimator
    Alan’s Roofing, Inc
    Brooksville, FL

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