If you are looking for a cost-effective and durable single-ply roofing system, a TPO roof can meet your needs. TPO roofing systems are quickly growing in popularity both in residential and commercial markets, offering the combined benefits of both EPDM rubber roofs and PVC roofs, but at a more economical cost than PVC. TPO roofing membranes offer a number of performance, installation and environmental advantages. However, because they are a fairly new product, there are some important considerations you need to be aware of before purchasing a TPO roof.
What is it?
A TPO roofing membrane is made from ethylene propylene rubber. Special technology is used to chemically bind together, rubber, ethylene ( an organic gaseous substance) and propylene (a byproduct of petroleum refining). At the end, numerous filler materials are added, such as talc, carbon filler and fiberglass. These fillers reinforce the TPO membrane’s strength and durability. A TPO roofing membrane has been specifically designed to have the advantages of a rubber roof, combined with hot – air weldable seams for extra durability. TPO roofing membranes have been manufactured in the US since the early 1990′s and are now the fastest growing segment of the US single-ply roofing industry.
TPO Roof Options
TPO roofs are manufactured to meet a variety of needs and design specifications. They are available in white, light gray, and black colors. White TPO roofs offer the best heat reflective properties are are consequently the most popular choice due to their energy-saving potential. TPO roofs come in two thicknesses options: 45 mils (.045″) or 60 mils (.060″). The width and length of the membrane can vary depending on the manufacturer, with an average TPO roof being 6 – 6.5 ft wide and 100 ft long.
TPO roofing membranes take the best features from its direct competitors EPDM and PVC, offering clients an innovative, energy-efficient and cost-effective roofing solution. TPO roofs are durable; resisting dirt, bacteria, algae and debris build-up. The flexibility of the membrane makes it highly resistant to tears, punctures and impact damage. This flexibility also allows for a building’s movement and setting, without compromising the roof’s performance. Moreover, a TPO roof can withstand damaging ultraviolet, ozone and chemical exposure. Hot-air welded seams are very strong, with seam strengths being as much as 3-4 times greater than EPDM adhesive and tape seams.
A TPO membrane is considered to be a cool roof and is Energy Star rated. This means that the membrane reflects the sun’s ultraviolet rays. This can significantly lower HVAC costs and make the interior temperature more comfortable during hot summer months.
As the demand for green roofing materials continues to grow, TPO is well positioned to meet this need, offering clients an environmentally – friendly roofing solution. The solar reflective properties of light color TPO roofs contribute to reduction of energy waste from HVAC systems. Moreover, reflecting sun’s ultraviolet rays leads to the mitigation of the heat island effect in urban areas and contributes to cooler interior temperatures inside and cleaner air free from smog outside. Also, TPO polymer does not contain chlorine, which is environmentally hazardous, and there are no chlorine-containing ingredients added during production. Importantly, TPO is one of the few 100% recyclable roofing materials available. The membrane can be fully recycled and used again in the TPO manufacturing process; the ground up “rework” gets incorporated into the bottom ply of a brand new TPO membrane.
Despite all its benefits, a TPO roof has some important drawbacks. The main one is the fact that because TPO is fairly new roofing material, many manufacturers are still working on improving their formulations to achieve the greatest durability and longevity at the lowest possible cost. This means, that not all TPO membranes are created equal, and some perform a lot better than others. Moreover, while strict ASTM standards have finally been established for TPO roofs, they also continue to be revised every few years.
Over the years, because of faulty chemical formulas, many TPO roofs have failed and needed to be recalled. Reported problems included seams coming apart, leaks and membrane failures, especially when exposed to excessive heat over a prolonged period of time. The good news is that reputable manufacturers have taken care of these issues and ASTM standards have been critical in achieving a base line of minimal acceptable performance and features. This means that if you choose to purchase a TPO roofing membrane, you are getting a product that does not have a long track record of flawless performance, but instead has a long track record of revisions and improvements.
What to Look for in a TPO Roof?
To safeguard yourself against potential roofing problems and membrane failure, there are some steps you can take to make sure you are getting the highest quality TPO roofing system.
The most important thing is to purchase your TPO membrane from a reputable manufacturer that has been in the TPO roofing market since the very beginning (at least for 20 years). Do not be lured by super low prices of new TPO manufactures who are now entering the hot TPO market to make money and have no real knowledge or experience manufacturing high quality TPO membranes. Also, only work with a manufacturer that offers a clear warranty policy on their TPO roofing product.
Moreover, if you are looking to take advantage of the TPO membrane’s cool roof properties, you need to make sure that the membrane you purchase meets the initial and three-year ENERGY STAR requirements. Note that some TPO manufacturers have not even been on the market long enough to meet the three year requirement for an ENERGY STAR qualification.
For best energy efficiency performance, purchase a TPO membrane with a smooth surface. This is critical, as a smooth surface offers the best protection against dirt and debris, which over the years severely reduce the roof’s reflective properties and lead to accelerated aging.
Durability and Longevity
To purchase the most durable TPO roof, make sure that the membrane can be welded at the highest temperature range. Poor weldability is one area where most problems with TPO membranes occur. Proper weldability will ensure greater productivity and more reliable seams. In turn, strong seams mean better wind uplift performance and fewer leaks.
Another important factor is thickness, you want the top ply of your TPO membrane to be thicker. It will cost you more, but will eliminate future problems, as thicker membranes offer greater protection against weathering and solar radiation. ASTM’s minimum required thickness is 11 mils, and its advisable that for best performance a TPO membrane’s thickness is over 20 mils.