Why TPO or EPDM?
The purpose of commercial flat roofing systems is to be able to cover much larger areas than residential roofs typically do. Although you mainly see shingle roofing systems for residential roofs, it is not advised for use on commercial flat roofs. The main reason is that water can easily get trapped underneath the shingles on a flat roof. With residential roofs, there is enough of a slope to allow for the water to run down naturally, however, in a flat roofing system, the water would become stagnant and begin to collect in a single area. This would lead to the shingles becoming saturated and weak, which will directly affect the performance of the roof. This is why commercial roofing contractors will recommend the use of a roofing system such as TPO or EPDM.
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What is a TPO Roofing System?
Thermoplastic polyolefin, also known by its acronym TPO, is a layer of a single-ply reflective membrane that acts as a combination of polypropylene and ethylene-propylene. TPO rubber provides flexible and weather resistant characteristics as well as having thermoplastic seams that are activated through a hot-air welding technique. Many may compare TPO and EPDM because of the quality that is present with the two roofing systems and many may say that TPO is another form of EPDM. The main reason for this is because many see both as “rubber roofing systems”. While this may be true, the membrane of a TPO roofing system is composed of three layers:
- TPO Polymer Base
- Polyester-Reinforced Fabric Center (Scrim)
- Thermoplastic Polyolefin Compounded Top Ply
Installation is also cost-efficient as it doesn't take a lot of resources or time to install a TPO roof. The membrane can be fastened or attached right to the roof deck and can be welded together at the seams to provide a water-tight connection.
Benefits of TPO
Even though EPDM roofing systems are used a lot more and has been an industry leader for more than half a century for single-ply roofing, TPO has been rapidly gaining in popularity on EPDM. Many roofing contractors can foresee that it will overtake EPDM as the preferred industry choice in the near future. TPO does offer a good amount of advantages, which is why it is a very popular commercial roofing material choice for commercial roofs. One of the biggest advantages that lead facility owners to TPO is its energy efficiency. EPDM has a dark surface, which during summer conditions would absorb the heat, forcing cooling systems to work overtime. Whereas a TPO roof usually has a light UV resistant surface that reflects sunlight, allowing commercial air conditioners to work more efficiently.
TPO has a considerably higher resistance to punctures in comparison to EPDM. When you look at EPDM’s resistance and TPO’s resistance to puncture, you would find that TPO offers roughly three times more protection against punctures. This is beneficial because it then can prevent any leaks when rain and hail starts coming down.
TPO, as mentioned before, is one of the cheapest material on the market today costing less than EPDM or other types of rolled rubber roofing. TPO is generally offered in white, which can reflect the sun’s light and stop heat buildup within the building. However, TPO is provided with other reflective color options such as light grey and tan. TPO roofing systems are always welded, providing an air-tight, seamless connection. TPO resists corrosion and disintegration upon contact with a number of different materials. It also doesn’t require pressure washing.
TPO resists mold growth, dirt accumulation, tears impact, and punctures. It is made to be flexible and can allow for a building’s movement or settling. Reinforced TPO membranes can also handle a building’s thermal expansion and contraction more effectively than other single-ply roofing products.
Disadvantages of TPO
Yes, TPO can save money on your energy costs and make your commercial building cooler, however, there is a set back when the temperature gets too high, as it can cause serious problems. States that generally are warmer over the course of the year would be affected compared to states that don’t experience warmer weather. If temperatures are pushed to a tremendously high level on a regular basis, TPO would not be able to withstand that kind of climate. Also, if a homeowner decided to go forward with installing solar panels and solar loads are increased far beyond the usual amount, it is entirely possible that the TPO roof could fail to withstand that kind of load. So, if you live in a climate where temperatures are typically high or you plan on installing loads on the roof such as solar panels, these are some of the issues you will regularly encounter. If this is the case, TPO roofing may not be your best option.
When being installed, TPO roofs are typically welded, in return making it extremely durable, however, on the other hand it can also complicate installation because the welding requires an electrical source. For this same reason, any repairs which might become necessary for TPO systems are harder to implement because electricity will be required to do the repair work.
TPO roofing has proven to be strong and durable, but it must be kept in mind that it is still a young technology. Not all TPO products are created equally, as the formula that is used to produce the TPO roofing material is continuously being perfected as the manufacturers attempt to find the proper balance between durability and affordability. Along the way, there have been some TPO models that have had some seam and material failures involving cracks. While improvements are constantly being made, it is impossible to know precisely how long TPO roofing will last. Most estimates only give TPO roofs a lifetime of 15-20 years.
What is an EPDM Roofing System?
Ethylene Propylene Diene Monomer, also known by its acronym EPDM, is known for its strong and durable synthetic rubber roofing membrane that is commonly used on low sloped and flat commercial roofs. Its two main ingredients, ethylene and propylene, are derived from oil and natural gas.
EPDM comes in a variety of different thicknesses, and comes in either white or black. EPDM can be installed either mechanically attached or ballasted, or fully adhered, with the seams of the commercial roof being sealed with a specially formulated tape or liquid adhesives. There is also no need for access to electricity, as EPDM roofs do not need to be welded for installation. EPDM has been around for over 40 years, but has continued to be one of the most cost-effective and energy-efficient commercial roofing systems available.
TPO vs EPDM
Both of these roofing systems are excellent at protecting your commercial building. Choosing one over the other may depend on your geographic location, taking into account the regular weather conditions that can affect the structure of the roof. It also can depend on external factors such as the intent to possibly mount solar panels on the roof. The important thing is to do your research on each of these roofing systems and to understand which one is better for your project. If you have further questions about these roofing systems or any other roofing topics, please don’t hesitate to contact us!