Technology in the commercial roofing business has made many advances in the last fifty Years. The introduction of the single ply membranes has brought about the three main roof coverings for flat roofs, EPDM, PVC and TPO. Each of these products have pros and cons. We hope this article will help you in your decision making process.
We’re writing this article as one of the premier commercial roofing companies in Utah, we want you to be informed of your flat roof options. Oakley Roofing is an approved applicator to install all three of these membranes. This allows us to offer our client the best warranty that our manufactures have to offer. When Oakley Roofing is your commercial roofing contractor you are given options as to the years of coverage and you decide which best suits your preference.
All roofs in Utah face extreme weather and climate challenges. Each building faces unique requirements. Many factors come into play when choosing the right roofing product for your building. Allow us to assist you in making this important decision.
A leak on a flat roof often is not detected for a long period of time. Water penetrates the membrane layer and saturates the decking and insulation before soaking through the structure beneath it. By the time the leak is noticed inside the building, considerable damage has already been done to the roofing system. Mold develops under the membrane and the roofing materials begin to rot. If left in place it weakens the roof structure. There are also health risks to humans and animals from breathing mold spores.
Ethylene Propylene Diene Monomer, (EPDM) rubber roofing is a commercial roofing membrane developed in the 1960s. DuPont, Exxon and Uniroyal Chemical discovered this polymer that provided more UV resistance and could withstand more weather than other products on the market.
At the time, asphalt roofing products dominated the roofing industry. It wasn’t long after DuPont developed a roofing compound using EPDM as the base ingredient that EPDM roofing membranes revolutionized the commercial roofing industry.
EPDM was a huge improvement over the asphalt roofing products already on the market. EPDM was more resistant to UV rays, more durable than asphalt roofing products and easier to install, which made it very popular with flat roof contractors in Utah. EPDM membranes became the new standard product for commercial roofing. EPDM is also ideal for residential flat roofs however it is still primarily sold through commercial roofing distributors.
Although tornadoes are rare in Utah, we do experience hurricane force winds throughout the state at certain times of the year. EPDM is highly resistant to wind damage which made it popular with flat roof contractors in Utah. EPDM roof systems can be designed to meet a variety of wind uplift criteria from Factory Mutual, including 1-60, 1-90 and 1-120 ratings or greater. Architects, engineers and roof contractors recommend EPDM with confidence because of its durability and long term performance.
As a roofing contractor based in Salt Lake City, UT, Oakley Roofing has installed over one million square feet of EPDM. As we follow up with past roofing projects, I see and talk to owners of EPDM roofs that we installed over 20 years ago. It is rewarding to see these roofs that are 20 plus years old and they still look amazing. To say these roofs have another 20 years of life expectancy would not be much of a stretch!
Of course many factors go into creating a roof that performs so well.
Workmanship is one key factor that cannot be over stated. Choosing the right Utah roofing contractor is as important as the right product.
Thermoplastic PVC roofing has been around since 1966. A German company used the membrane as a roofing cover. The membrane had catastrophic failures. The PVC sheet was changed and reinforced. PVC evolved into what we use today and has become a leading commercial roofing membrane. PVC is extremely strong. PVC resin is modified with UV stabilizers, plasticizers and reinforced with polyester woven scrims or fiberglass non-woven mats for use as a flexible roofing membrane. The seams are heat welded to form a permanent water tight bond that is stronger than the membrane itself.
Due to their chemical composition, PVC roofs are resistant to fire, air pollutants and chemicals. PVC is also an excellent membrane for restaurants because it is highly resistant to animal fats. PVC membranes are the best choice for commercial roofing when harsh environments are a factor.
PVC roofs are energy efficient due to their light coloring. The surface of a black roof can increase as much as 90 degrees Fahrenheit under the full heat of the sun, whereas a reflective white roof may only increase 10 -25 degrees.
Although PVC is superior to other commercial roofing products in harsh environments, it does have a weakness. PVC is subject to a process called “plasticizer migration.” This occurs when plasticizers migrate out of the sheet causing it to become brittle. Typically when using PVC the roofing contractor will recommend a thicker membrane (than with EPDM) which has a greater supply of plasticizers, allowing the membrane to maintain flexibility over its lifespan.
In 1994 Oakley Roofing was awarded a roofing contract at the SLC International Airport. The Roofing Specification called for an EPDM roof membrane. After careful consideration and given the harsh environmental conditions (jet fuel) the architect changed the roof spec to a Fully Adhered 90 mil. PVC, Genflex system. The change was a good call. The roof is now 19 yrs. old and looks like new.
Thermoplastic Polyolefin (TPO) is the latest of the single-ply commercial roofing membranes. TPO membranes were developed as a “hybrid” drawing from the strengths of EPDM and the PVC membranes. Like PVC membranes the seams are heat welded which provides a solid waterproof bond that is 180% stronger than adhered seams.
Flat roof contractors like TPO membranes because they are easy to install using one of three methods:
1. The membrane can be mechanically fastened to the decking with screws.
2. The membrane can be glued to the decking with an adhesive designed for TPO membranes.
3. Ballasted: the membrane is laid over the decking and a layer of rock is spread out over the membrane to hold it in place.
The rock offers some protection to the membrane from UV rays, but can make it difficult to locate a leak if one occurs.
TPO is a popular choice among Architects and roofing contractors for “Green Buildings” due to its “Energy Star Rating.” The commercial roofing membranes are available in white, gray and black. The lighter colors reflect the sun’s rays reducing the (heat island effect) solar heat gain in the building.
Manufacturers of TPO have experimented with the properties of their membrane. Now each manufacture has a formulation of their own. TPO membranes may not have the years of proven performance behind them, but with each passing year and with the acceleration tests confidence is continually growing. Evidence of this is in the manufactures expanding warranty coverage’s.
Oakley Roofing recently installed a 20 year No Dollar Limit Warranty on the Mill Creek Recreation Center in Salt Lake City, Utah. This is a 60,000 Sq. Ft. roof. Versico has confidence that this warranty will not cost them money. Warranties range from the basic 10 Yr. Material warranty to a qualified 20 NDL warranty.
In Salt Lake City and throughout Utah, TPO is currently the most widely installed commercial roofing membrane. Price seems to be one factor contributing to TPO’s popularity in Utah. TPO is the least expensive membrane product on the market. Roofing contractors like TPO because it’s easy to install, welded seams provide superior strength and the manufacturers warranties are competitive with other membrane products.
Oakley Roofing keeps files on all our roofing projects so we can provide our own performance data of the materials we’ve used in roofing across Utah. Periodically we inspect our roofs to determine their strengths and where they are likely to fail. We have kept these records for 20 years and can give an honest, impartial evaluation of how these roofing products have performed under Utah weather conditions.
The first TPO roof we installed was in Vernal Utah, 2001. The manufacturer was Genflex. It was a .45 mil, Fully Adhered System. While we have had no issues with this TPO roof, we have had issues on other TPO roofs. The primary problem: the drip edge cover tape tends to delaminate from the unsupported cover. The manufactures have experimented with this product and all claim to have it figured out. However we avoid the using the tape and weld onto TPO clad metal where ever possible.