Senior project written by Riess Stanley
Nov 4, 2010
With economic strife on the rise, it has now become necessary to seek out ways to save money, as well as to find ways to “stay green”, and to do what you can to help the environment. Unfortunately, accomplishing both at the same time seems to be very difficult. Believe it or not, there is a smart, fairly simple, and very efficient way to succeed in these two areas in a way not often looked upon as a money saver, but rather a necessary and costly project when it doesn’t need to be; the roof. When you really get down to it, the roof is either costing too much, or saving plenty.
First off, if a building with a flat or low-sloped pitch was to have a black tar roof, it would be taking more money than one would realize. In warm weather, the black roof will absorb so much heat that an abundance of energy and money would need to be invested into cooling down the building. Moreover, all that heat beating down on the roof will make it crack, which in turn will cause it to leak once the rainy weather begins. This defeats the entire purpose of a roof. So, what is a low cost alternative for a black tar roof, that can keep the roof cool during summer months and can keep out the rain? The answer; PVC (Polyvinyl Chloride) single-ply membrane.
PVC membrane is a very efficient, low cost (it may seem expensive, but saves money over time), and durable roofing material, and with it’s commonly white colored facing it actually reflects the sunlight, allowing the building to stay cool without costly electricity bills. Another great feature of PVC is that it doesn’t cure, meaning that if a repair is needed to be made five, ten, or even 20 years after the initial installation, the material is still weldable, making it only a little patch job to fix the problem (Leo).
Here is usually where the good news comes to a halt, after hearing about money savings. Now is the time for what one does not often hear; how saving money also includes being environmentally friendly. It’s one thing to say that a roofing material is recyclable, and another to actually have a roofing material, currently, being recycled. IB Roof Systems is a company doing just that, and they are proud of having some of the longest lasting sustainable roofing membranes in the industry with an incredible track record to back it up. They are also proud to be able to start reclaiming and recycling those same roofs after their long useful life is over. After 30 years of great performance, IB Roof Systems membranes are being recycled into other high quality products, avoiding the landfill altogether.
Jeff Walter from Northwest Polymers, a plastics recycling company, stated, “From what we have seen so far in processing the aged PVC membrane material, there is very little waste. As it passes through our system we are recognizing about 99.5% of good, usable materials.” He also stated that, “one of the good things about vinyl and plastics is that they last for such a long time, the material is still very usable, degradation is minimal, and because of this, it can still be made into good products even when it has already served for 30 years” (Stanley).
Some home owners might want to take it all a step further, and build a rooftop garden. Rooftop gardens offer wonderful long-term benefits to the building and the environment. However, creating these mini eco-systems on the rooftop requires a large investment, therefore it is vital to the success of the rooftop garden that a proven, durable waterproofing system be put in. This is where PVC can really show its strength, for it is impenetrable to strong root systems and can handle constant or pooling moisture. It’s resistant to high PH or acidic soil conditions, and has a continuous leak-free performance, proven to last for at least 30 years (Rooftop Gardens).
As great as all of this is, there are ridiculous and outlandish claims about PVC, as it is moronically labeled the “poison plastic”. It is almost funny the way these groups seethe about the life cycle of PVC and how only 1% is recycled at an exceedingly high cost, or that “Many recycled PVC products have to be reestablished with toxic heavy metal compounds or other stabilizers”, when in reality (as stated above) 99.5% of PVC is recycled after it has served its purpose for 30 years, only to protect another faithful roof owner for 30 years (The Poison Plastic).
As PVC is a major thermoplastic membrane on the market, there is also TPO (Thermo Plastic Olefin). Although these two are both widely used, TPO has many problems and shortcomings in comparison to PVC. PVC is a thermoplastic membrane utilizing a reinforcement scrim between the two plies of equal thickness (IB Roof only). The top ply contains Cool Roof pigments, UV stabilizers, and other components to extend the life of the membrane. The bottom ply contains PVC ingredients to provide consistent weld of top and bottom plies and fillers. TPO is also a thermoplastic membrane utilizing a reinforcement scrim between the two plies, yet 35% thickness for the top and 65 % thickness for the bottom ply. The top ply, like PVC, also contains Cool Roof pigments, UV stabilizers, and other components to extend the life of the membrane. The bottom ply contains TPO ingredients to provide consistent weld of top and bottom plies and fillers. Note that the top ply is about half the thickness of the bottom ply, yet the top ply is the one that makes the roof long lasting. IB’s PVC has an equal thickness of top/bottom ply.
TPO roof systems are under continuous development by numerous manufacturers, who constantly change the TPO formulation to achieve the lowest cost with “acceptable” performance. While it is understandable that business always look to save money and to reduce costs, these constant TPO development processes are being conducted, often at the expense of the roof owner. A TPO roof from the same manufacturer will most likely NOT be the same as the one produced few years before or after. Also the quality of different batches of TPO membranes may be questionable, as some TPO producers release the product to the end user without getting the UL (Underwriters Laboratories) and similar approvals/certification, as the formulation changes too often (Leo 2).
The TPO resin is compounded with other components, including a weathering package, fire retardants and pigments to create a product that can withstand the elements associated with rooftop exposure. TPO itself is not fire resistant and requires the addition of fire retardants to obtain a fire rating. The ratios of weathering material and fire retardants are still inconsistent from manufacturer to manufacturer (Warseck).
PVC single play flat roofing is by far the best choice for any type of flat roof. The main advantage of PVC membrane is that the seams are hot air welded creating a physical bond between the sheets that is stronger than the membrane itself. Such a seam is a permanent seal, ensuring that there will be no leaks even if you have puddles of pooling water on the roof (Leo 2).
So what makes PVC the best single-ply roofing membrane? PVC is a low cost, high performance membrane, which can withstand up to 30 years of all weather conditions. Not only can it stand up against the elements, it is also the best choice for supporting a rooftop garden, with it being able to stand against strong root systems and the constant pooling of moisture. PVC’s white face even reflects UV rays allowing the building to stay cooler easier, with the use of less energy, thus reducing carbon impact. If an accident might occur and the membrane would need repair, it doesn’t cure, meaning that the material is still weld-able making it only a little patch job to fix the problem. PVC is also naturally fire resistant. Another great aspect of PVC is that it has a thicker topcoat than it’s counterparts, making it much stronger for harsh weather conditions and giving it a much longer lifespan. Once it has exceeded those 30 years, it is then recycled to be used once more, keeping the environment and all of its inhabitants as safe as possible.
Leo. Flat Roof & Metal Roofing MA. IB Flat Roof Systems, 15 June 2009. Web. 6 Jan. 2011. .
Leo (2). “Single-Ply Flat Roofing Membranes – PVC, TPO & EPDM Rubber Roofs.” Flat Roof & Metal Roofing MA. IB Roof Systems, 15 June 2009. Web. 13 Jan. 2011. .
“Rooftop Gardens.” IB Roof Systems. N.p., 2005. Web. 13 Jan. 2011. .
Stanley, Shawn D. “Reclamation.” IB Roof Systems. N.p., 2005. Web. 11 Jan. 2011. .
Green Peace International. “The Poison Plastic.” N.p., 2 June 2003. Web. 11 Jan. 2011. .