TPO membranes are single-ply roof membranes constructed from ethylene propylene rubber. They are designed to combine the durability of rubber with the proven performance of hot-air weldable seams. They have been tested as having excellent resistance to ozone, are algae-resistant, environmentally friendly and safe to install.
Thermoplastic roofs are often advertised as seamless because properly welded seams are 3 to 4 times stronger than those of EPDM's adhesive and tape seams. The welding process itself creates a bond that is stronger than the TPO sheet itself.
COMPOSITION
TPO roofing membrane is typically based on polypropylene and EP (ethylene-propylene) rubber polymerized together using state-of-the-art polymer manufacturing technology. This technology enables the production of TPO membranes that are flexible at low temperatures. Unlike some other popular thermoplastic roofing membranes, the TPO polymer does not contain chlorine, which marks TPO as one of the most environmentally safe products. The TPO resin is compounded with other components including a weathering package, fire retardants and pigments for color to create a product that can withstand the elements associated with rooftop exposure.
INSTALLATION
TPO roofing membrane is typically installed using mechanical fasteners and plates placed along the edge of the sheet and fastened through the membrane and into the roof decking. Adjoining sheets of TPO membrane are overlapped, covering the fasteners and plates, and joined together with a minimum 40 mm (1 1/2 in.) wide hot air weld.
The membrane may also be fully adhered to an insulation or deck material using an adhesive. Insulation is typically secured to the deck with mechanical fasteners and the TPO membrane is adhered to the insulation. This type of system is highly resistant to wind and its associated uplift forces. The fully adhered system is ideal for very visible roofs such as domes or other high slope applications.
WELDABILITY
One of the primary benefits of TPO membrane is the ability to fuse the sheets together with a hot air weld. The welding process results in a bond that is actually stronger than the sheet itself. Flashing details, such as exhaust vents, pipes and parapet corners are also completed using hot air welds and flashing material (typically non-reinforced).
TPO membrane has a wide window of weldability, allowing the roofing applicator to complete hot air welds consistently in a broad temperature range. TPO is a thermoplastic material and does not “cure” on the rooftop once installed. This allows the sheet to be repaired with proper surface preparation after rooftop exposure.
WIDE SHEET TECHNOLOGY
Another benefit that Firestone TPO membranes brought to the roofing community were wide width sheets. Currently, TPO membranes are manufactured in widths up to 12'. These wider sheets provide installed cost savings by reducing the total number of seams to be completed in the field and the labor associated with the seaming/welding process. Wider sheets also require fewer fasteners and plates for membrane securement, fewer rolls for the roofing applicator to handle on the roof, and less membrane being utilized in the seam overlaps.
FIRESTONE TPO OPTIONS
UltraPly TPO
UltraPly TPO offers design options with membranes available in reflective white, tan or gray, which can help reduce a building’s cooling requirements.
UltraPly Platinum
UltraPly Platinum TPO features Firestone Wide-Weld technology to provide the industry's widest field seams and highest wind rating, while its scrim-reinforced membrane offers enhanced puncture, tear and abrasion resistance. The reflective surface of UltraPly Platinum TPO meets EnergyStar® standards for energy savings in warm climates, making it an exceptional long-term roofing value for building owners.
ReflexEON
Backed by more than 10 years of field and laboratory testing on actual rooftop installations, Firestone ReflexEON TPO is the first thermoplastic roofing membrane to greatly reduce the effects of microbial growth, and the subsequent staining and loss of reflectivity.
UltraPly TPO XR
Firestone UltraPly TPO XR combines the durability of a single-ply membrane with the heat welding properties of thermoplastic in an adhered application. Installation flexibility enables the roofing system to be installed with either hot asphalt or Firestone UltraPly TPO XR Bonding Adhesive.
FAQ
- What is TPO?
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TPO roofing membrane is typically based on polypropylene and EP (ethylene-propylene) rubber polymerized together using state-of-the-art polymer manufacturing technology. This technology enables the production of TPO membranes that are flexible at low temperatures without the use of polymeric or liquid plasticizers. Unlike some other popular thermoplastic roofing membranes, the TPO polymer does not contain chlorine and no chlorine-containing ingredients are added during sheet production, making it one of the top green roofing materials available.
The TPO resin is compounded with other components including a weathering package, fire retardants and pigments for color to create a product that can withstand the elements associated with rooftop exposure. The membrane is comprised of TPO based top and bottom plies encapsulating a reinforcing fabric that enhances the physical properties of the sheet. The combination of the fabric and TPO plies provide reinforced membranes with high breaking and tearing strength and puncture resistance. Sheet widths are available up to 3.66 m (12 ft) and membrane thickness is typically 1.1 or 1.5 mm (0.045 and 0.060 in.), however, membrane up to 2.0 mm (0.080 in.) is available.
- How can TPO lower my electricity bill?
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Another important characteristic of TPO membrane is its high level of reflectivity. Because of this, white TPO membranes can meet and even substantially exceed the U.S. Environmental Protection Agency’s ENERGY STAR performance levels.
Those ENERGY STAR marks that have been posted on refrigerators, water heaters and other appliances for years now can be seen on rolls of white TPO membrane. White TPO membranes typically display reflectivity ratings in the high 80 percent range when new (ENERGY STAR specifications require 65 percent minimum) and in the low 80 percent range after three-year rooftop exposure with cleaning (ENERGY STAR specifications require 50 percent minimum).
TPO membranes are highly resistant to mold and algae growth, which can degrade the overall reflectivity of the roof and reduce anticipated energy savings.
- Is TPO environmentally friendly?
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TPO membrane, reinforced and non-reinforced, is 100 percent recyclable during the production process. During production, if the need arises, the membrane can be ground into “rework” and this regrind can be incorporated into the bottom ply during the extrusion process to produce new TPO product. This process results in 100 percent reuse of recycled product.
- How does TPO compare to other roof systems?
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Expansion and contraction, ponding, moisture, thermal shock, and temperature extremes are all factors that promote premature degradation of a roofing membrane. TPO has great elongation capabilities and low temperature flexibility to accommodate building movement in various climatic conditions without stressing the material. Its moisture absorption resistance allows the material to be installed in assemblies with lesser slope than other single-plies and makes it tolerable to incidental ponding and deflection.
Unlike built-up roofing, TPO membrane does not contain organic material that can decay as the result of moisture caused by condensation or leaks. Due to its ability to withstand extreme temperature, can be successfully used in assemblies with greater thermal resistance (thicker insulations with higher R-values). The ability of a roofing membrane to withstand temperature extremes is an important trait of a high performance material because temperature extremes could promote premature membrane aging and reduce the life expectancy of a roof.
The ability to hot-air weld TPO membrane sheets together is what sets it apart from EPDM. Whereas EPDM has an adhesive layer added between the overlapping sheets, TPO is literally welded together to create one continuous sheet. As long as the process is done correctly, it ensures there will be no leaks throughout the service lifetime.
- How popular is TPO?
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TPO-based products have been used in various applications, including the automobile industry since the 1980s, and have seen their usage continue to expand.
In 1989, TPO-based membrane moved into the roofing industry as a non-reinforced sheet. In 1993, the original non-reinforced TPO membrane was replaced with membranes containing reinforcing fabric.
Since that time, the TPO single-ply roofing market has grown to hundreds of millions of square feet annually with TPO membrane comprising the fastest growing segment of the U.S. single-ply roofing industry.
- What is the Expected Service Life of TPO?
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We first started installing TPO roofs in 1995. Many of the original TPO roofs are still in use today. We have even been able to make reliable, strong repairs to this membrane, even after 15 years of service.
- Can TPO be repaired after aging?
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TPO is a thermoplastic material and does not “cure” on the rooftop once installed. This allows the sheet to be repaired with proper surface preparation after rooftop exposure.
The characteristics of the membrane are such that, even after years of field service and exposure to the elements, repairs and/or modifications, such as the installation of a new rooftop unit, can be accomplished with ease and with the expectation of long-term performance.
MORE INFORMATION
Firestone Building Products - TPO System Specification Sheets (MSDS/TIS)