They may be similar in appearance, but the answer is no, significant differences exist that are important when considering the purchase of a commercial roofing system.
Installation cost, total system service life, annual maintenance requirements, and warranties all vary from system to system.
In this article, we will discuss and compare TPO vs PVC roofing systems. It is important to be aware of the different benefits each system offers when considering a new flat or low slope roof system for your facility.
PVC or TPO Roofing: Experience and Properties
Polyvinyl chloride, also known as PVC, has been on the market since 1966 while thermoplastic polyolefin), referred to as TPO, was developed around 1991. Both are known to be one of the most common commercial white roofing membranes currently available.
Duro-Last has a widespread number of distribution centers in the U.S and is headquartered in Michigan. As the largest manufacturer of custom fabricated PVC membrane roofing, it serves to fill customer’s needs for durable PVC roofing material since Duro-Last PVC membrane consists of three layers, a top sheet, reinforcement scrim, and base sheet.
The top sheet is the performance layer located above the scrim with the purpose of facing weather, airborne pollutants, wind-blown dirt, ultraviolet radiation, and heavy foot traffic.
Duro-Last has the thickest performance layer available among any other roof membrane offered on the market and provides the long-lasting and potentially maintenance-free service during its shelf life.
The middle layer consists of a reinforced scrim that is weft-inserted and has anti-wicking properties. Its thread count and strength contributes to the overall durability of this middle layer and three-part assembly. With the highest thread count in the industry at 18×14 threads per inch, Duro-Last’s flagship membrane is a vital element chosen among commercial roofing companies.
The third layer is mostly found at the bottom or base layer and is not exposed to weather elements. Therefore, it is composed of less expensive material.
Two of the primary membranes that Duro-Last provides are: a high quality top layer material in both layers made with the same Duro-Last flagship membrane offered since 1978 and an alternate membrane made from a lower cost base layer which as a reduced scrim thread count called Duro-Tuff that’s been available since 2012.
Duro-Tuff has a reduced price tag and can be applied in a ample variety of situations, however, both systems provide excellent results. In addition, both systems and other specialty products are manufactured at the Saginaw, Michigan headquarters using top of the line laminating and extruding equipment
Due to the chemical composition of PVC systems, PVC roofs display exceptional properties such as strength, flexibility, fire retardant and resistance to most chemicals.
TPO is essentially comprised of the same three-part structure but significantly varies in the materials used. Polypropylene, ethylene-propylene rubber, and various fillers such as carbon, fiberglass, or talc mixed with polymers are what mainly TPO membranes consist of.
When comparing different membranes of the same thickness from Duro-Last or TPO, the performance layer in TPO is more thin than those found in PVC membranes. In addition, the scrim is not weft-inserted and generally has a lower thread count, along with the base layer of TPO being of a lower quality material and a greater percentage of fillers.This results in TPO proving flexibility, aesthetic appeal but with reduced resistance to punctures, tears or chemicals, as well as more likely to be burned when exposed to fire when compared to Duro-Last PVC membranes.
PVC or TPO: Sustainability
The National Science Foundation created a new standard in 2009, NSF/ANSI 347, which measures and evaluates the sustainability of single-ply roof systems during its whole life cycle.
The five areas used to assess each single-ply roofing system include its product manufacturing, membrane durability, product design, corporate governance, and innovation.
The NSF/ANSI 347 standard in combination with one gold and two silver certifications has been attained by Dur0-Last and its sustainability certified with five of its most popular membrane options, including recognition of its PVC membrane recyclability and declarations of their environmental products. The best part is that after the Duro-Last membranes have reached their peak life usage, it can be returned to the Duro-Last’s recycling center located at the Saginaw Michigan facility.
The National Science Foundation has not certified TPO membrane’s recyclability due to its questionable nature.
PVC or TPO and their Energy Efficiency
Selecting the proper roof that suits weather conditions common to your area during the summer months in which high temperatures are experienced can have a great impact on just how energy efficient and comfortable your property remains. .
The Solar Reflectance Index (SRI) is key in flat roofers understanding how to get your roofing system as cost and energy efficient during any flat roof construction. The SRIvof PVC and TPO membranes measure how hot the roofing surface may become under total exposure to the sun. The SRI number is first measured for each roof type when its membrane is new and again after three years of exposure. A higher number points to a roofing material being better at inhibiting heat transferring into the building.
The initial SRI of Duro-Last white 50 mil PVC membrane boasts an 88% reflection of the sun’s energy and has an initial SRI reading of 111 and after the 3-year period when it’s measured again it’s at 82, primarily caused by air borne contaminants and dust found on its membrane surface.
The initial SRI for TPO was reported to be 77, with a decrease to 70 after the third year.
PVC membrane is the more efficient choice when it comes to keeping heat radiated away from the property, instead of it passing through.
Air conditioning (A/C) units are among the fastest-growing energy appliances and the costs associated with maintenance and replacement of A/C systems is also climbing.
All Roofs Inc can help you choose the roofing system with the highest SRI to ensure you receive the added energy efficiency which helps extend the shelf life of your A/C systemChoosing a roofing system with a higher SRI may help improve energy efficiency, extend your A/C system life, along with lowering energy costs.
PVC or TPO: Installation Methods
The method of installation for PVC and TPO normally entails either being mechanically fastened or fully adhered, depending on the customer’s preference and type of structure. Field labor requirements and the quality of the final installation may vary among Duro-Last roofing systems and TPO.
Skilled crewmen are required to be on site when fabricating most of the flashing details of TPO. Weak workmanship is the main cause for most roof failures or leaks, as well as contractors working in adverse weather conditions such as heavy wind, extreme temperatures and precipitation. Reduction of field work requirements is one practice used to prevent future roof problems and reduction of on site labor demands and costs. Duro-Last facilities are the ideal home to the custom fabrication that Duro-Last provides for all rooftop flashing details and optional custom fabrication of deck sheets done in house under the perfect factory conditions.
You will receive guaranteed, quality installation that is in line with our reliable Duro-Last custom fabrications for which only a skilled team of experienced professionals used to handle your project. Careful measurements will be taken of the rooftop penetration and adjacent details of the property by our project managers so that the flashing components can be custom prefabricated. This eliminates any complex flashing work from being done in the field.
PVC or TPO: The Cost
Budget considerations are key to ensuring your project results turn out as expected. When looking at the costs involved with flat roofing installation, on site labor and roofing materials must be included. As a property owner, you must decide what is the most important aspect you should invest in.
The labor team leaves the project site once the job is done. However, the material will remain and is there to ensure your property, inventory, equipment and staff are protected.
The prefabrication of Duro-Last PVC saves on site hours whereas TPO cannot since its non-prefabricated roofing. This results in more of your investment being used on the roofing system instead of on the labor that was only there for the beginning.
Maintenance and service costs should be considered during its lifespan since the least expensive roof is the one with the lowest annual ownership cost. The cost per year to own a roof can be calculated by adding the cost of the project plus annual maintenance, then dividing that by the expected service life. It may be wise to invest more up front if the roofing system will require less maintenance and a longer service life.
Other factors that need to be considered are the differences in PVC and TPO’s repairs or upgrades that may need to take place over time.
As TPO membranes age, they become harder to work with and may require difficult or costly repairs or replacements,whereas, PVC membranes can be repaired by the same hot air welding technique used during its initial installation.
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