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Will A Rooftop Pipe Support Damage A Single-Ply Rooftop Membrane?

First off, let’s define what a single ply membrane roof is and where it is used. Single ply membrane roofs are sheets of rubber or other synthetics that can be ballasted or chemically adhered to insulation to create a layer of protection for your commercial facility. Single ply membrane roofs are used on flat of near flat roofs, typically on commercial buildings.

There are 3 main types of single ply membrane roofs. They are EPDM, TPO and PVC. Each material has its own sets of pros and cons. To make an informed decision, we will go over the traits that each material possesses and the weaknesses that you will want to know about.

EPDM

EPDM, commonly known as a “rubber roof”, stands for ethylene propylene diene monomer and gets its name from the chemicals (monomers) that are mixed in various proportions to form it.  It is most used on low-sloped or flat roofs, typically on commercial buildings. However, it is also used on residential structures such as car ports and patio roofs.

Roofing membrane
EPDM is manufactured in large sheets or rolls; it is quick and easy to install. This is one of the advantages of EDPM roofing, the reduced installation cost. At approximately $0.80/square foot, EPDM is one of the most inexpensive roofing materials around. EPDM roofing membrane is very lightweight, so the roof deck will not need any reinforcement. In fact, one of the most efficient ways to install EPDM on a roof is to simply strip everything off the roof, apply an adhesive, then roll out the membrane. Because there are few seams, leaks are rare (As long as the installer follows the manufacturer’s directions) and a good quality EPDM can last 20+ years.

Contractors have the option of how they will install the material. In addition to using adhesive to attach the material to the roof, there are also fasteners that can be used to anchor it in difficult to reach areas. I can also be ballasted with stone, which can help improve its appearance. Check out our blog on how to adhere EPDM to EPDM here.

Pros & cons of EPDM

Pros
  • EPDM generally comes in at the lowest price per square foot for flat or low sloped roofs.
  • EPDM is generally long lasting with a lifespan of over 20 years.
  • Since it is easily paired with polyiso insulation, it can be a very energy efficient roof choice, especially if purchased in white.
Cons
  • EPDM can be fragile in the wrong environment and at near its end of life.
  • Ballasted EPDM systems are relatively inexpensive when compared to others, however fully adhered or mechanical systems are slightly more expensive than TPO.
  • There is a common thought that the black flat EPDM roofs are not the prettiest sight to look at.

TPO

TPO, which stands for Thermoplastic Polyolefin is possibly the fastest growing commercial roofing system on the market. It is made up of a single layer of synthetics and reinforcing scrim that can be used to cover flat and semi-flat roofs. The name is a bit misleading, because rather than being plastic, TPO is one of a few different types of rubber, usually a blend of polypropylene and ethylene-propylene rubber. The main advantage of TPO is that it is typically the lowest material cost for single ply membrane roofs, costing less than EPDM and other types of rolled rubber roofing. The next advantage to point out is the color. TPO typically comes in white on top, which can help reflect the sun’s light and stop heat buildup within the building.

Other positives to TPO membrane are that it offers choices as to how it can be installed. It can be attached with adhesives or fastened directly to the roof deck. It can also be heat welded in places around chimneys and other protrusions.  Check out our blog on how to hand weld a TPO seam here.   Finally, TPO resists corrosion and breaks down upon contact with numerous materials. It also does not promote mildew or algae growth and does not require pressure washing. Because of these traits, it makes the material even easier to care for during the annual checkup.

The Pros & Cons of TPO

Pros
  • Provides outstanding resistance to ozone, ultraviolet rays, and some chemical exposure at a low cost.
  • Reflects heat radiation – better than EPDM.
  • Resists mold growth, dirt accumulation, tears impacts and punctures.
Cons
  • Heat welding the seams requires a very high-quality installation to hold up over time
  • Some formulations of the material may not last much past the 10-year mark
  • Newer technology makes for a lack of proven track record

PVC

PVC, which stands for polyvinyl chloride is another single ply membraned roofing solution used on flat and semi flat commercial buildings. It is made from a lower percentage of oil and petroleum than TPO or EPDM. As a cool roof membrane, its carriers both Energy Star and Cool Roof ratings. PVC is surprisingly strong, which is shown in the breaking strength which is at least 350 pounds per square inch – far above the minimum breaking strength required by the ASTM, which is 200 pounds per square inch. Because PVC is so strong and stable, it can be installed by heat welding the seams, as opposed to other membranes that require adhesive or utilize a taped seam. This installation method allows a PVC roof to expand and contract with a building. PVC can also be sealed with solvent welding and attached to metal flashing and other components with adhesives.

Pros & Cons of PVC

Pros
  • Strength – these roofs will typically last 20+ years
  • Resistant to chemicals and fire – Some commercial buildings, like warehouses and manufacturing facilities, will have significant amounts of exposure to chemicals. PVC roofs are also do not support combustion, burn slowly, are difficult to ignite, and even extinguish fire if the source is removed.
  • Recyclable & Eco friendly – It is highly efficient with heating and cooling and, reflects the sun and mitigates the heat island effect in cities. Oh, and it is recyclable, even after years of service life.
Cons
  • Cost – despite the benefits of PVC roofing, these features all come at a cost. It typically has a higher price per square foot cost than both EPDM and TPO.
  • Installation – If this is a re-roofing job, you will need to completely remove the old roof before moving forward with the replacement, this also adds more cost to the job as it can be very labor intensive to remove the old roof.
  • PVC roofing systems typically do not perform as well in cold climates. When it becomes too cold, PVC becomes brittle and can crack or even shatter if walked on.

Summary

As each membrane has its own unique pros and cons, this list should give you an idea of what traits you are looking for in your roof and help narrow in on the best choice for you. EPDM is a low-cost material however it can be more prone to damage and other mold/mildew build up and it is not the best roof to look at. TPO is a low-cost choice as well and reflects sun rays and heat to keep the building more energy efficient. TPO is a newer product to the market and the jury is still out to see if it can hold up for similar durations compared to PVC and EPDM. PVC is the highest price point of the three single ply membrane roofs we discussed but it is also a proven roof system that is strong, durable, and ecofriendly.

At Clearline Technologies, we have decades of experience in designing and manufacturing rooftop pipe supports that will not only do the job intended, but also outlast the roof that they are being installed on. From roller supports to crossovers and rooftop walkways, out team can work with you to design the perfect system for you. Check out our full line of supports below or give us a call at 866-444-0009.

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