Membrane Roofing Alternatives
The chart on the right shows the most recently available market share data regarding the popularity of various low-slope products in North Amercia. Of the alternatives shown, installations of “Modified Asphalt” systems that includes SBS Modified Bitumen “torch-on” roofing have been steadily declining over the past decade and it is believed that the current combined market share of the other three shown products (i.e EPDM, TPO,and PVC) could be as high as 80%.
The below chart identities the Global Warming Potential attributable to each of these low-slope roofing products as a result of their production processes and raw material inputs.
It is important to note that after a product is manufactured, the length of service life it provides and whether or not it is a recyclable product are also factors that must be taken into consideration in judging a products overall desirability from an environmental perspective. In that regard:
- Environmental Impact of EPDM and TPO Systems: TPO and EPDM systems must be considered the most environmentally desirable roofing materials. Based on the above chart, both are calculated to have “carbon neutral break even points” of 20 years or less, this meaning they must provide service lives of at least this length to be considered environmentally attractive. EPDM has been installed in North America for 50 years and studies are showing that EPDM roofs have the potential of providing service lives of double the length of their carbon neutral break-even points. The jury, however, remains out with respect to TPO as it has only been installed for the past 20 years with the first ones just now reaching their carbon neutral break even points, so only time will tell what service lengths these roofs will actually provide. Both EPDM and TPO are recyclable products, but only recycling of EPDM is currently available locally. There just hasn’t been enough TPO coming off TPO roofs yet for a local recycling program to have been established for it.
- Environmental Impact of PVC Systems: In the foregoing chart, PVC is shown as making a high potential contribution to global warming. The reason for this is that large proportion of the PVC manufacturing process incorporates use of natural gas. Offsetting this, however, is the fact that PVC roofs have been installed for some 40 years and have proven themselves capable of providing lengthy service lives. This coupled with the fact that PVC is a readily recyclable material makes PVC roofing an environmentally acceptable alternative. Duro-Last for example has an active program in place to turn both its manufacturing waste and old PVC roofs into a variety of new PVC products including vinyl flooring products.
- Environmental Impact of SBS Modified Bitumen “Torch-on” Systems: Torch-on roofing is absolutely the worst possible roofing choice from an environmental perspective. As noted below, while torch-on roofing continues to account for over 70% of BC low-slope roof installations, it was rejected for use in 23 Vancouver 2010 Winter Olympic roofing projects due to the Games’ requirement that materials used in conjunction with it needed to be environmentally sustainable “green” products. Due to this requirement, the BC roofing industry was forced instead to install TPO for these projects. However, in the five years since the Games, the industry has simply reverted back to very predominately continue to promote the installation of torch-on roofing. While many roofing industry consultants recognize that “newer asphalt assemblies are presently being observed as lasting only 15-18 years due to the drop in asphalt quality”, they continue to heavily recommend the installation of this product on the industry’s behalf. From an environmental perspective this, simply put, is reprehensible and disastrous. Based on the foregoing carbon footprint chart, the “carbon neutral break even point” for torch-on roofing is calculated 54.8 years, the implication here being that torch-on roofs need to be providing services lives of at least 55 years or more to be environmentally acceptable. They are, by the industry’s own admission, only providing 15 year service lives. This means that a first torch-on roof will have been in a landfill for some 40 years (along with 3 others for shorter periods) before the first one will have technically reached its carbon neutral break even point. Once in a landfill torch-on roofing will begin to leach its asphalt, styrene and other “modifier” chemicals into the environment for centuries. In the face of this situation, TechPro strongly recommends that wherever possible any “modified” roofing materials be left in place in the hope that in 30 or 40 years when their new TPO, EPDM or PVC roof has reached the end of its service life that a local recycling program will also be available to keep “modified asphalt” roofing materials out of out landfills.
Introduced in the mid 1990s TPO (Thermoplastic PolyOlefin), is a thermal plastic material offering the advantage of secure heat welded seams. TPO is manufactured in white, gray and beige colours. White membrane roofs are capable of reflecting 85% or more of the sun’s UV rays. This capability results in roof top temperatures that are as much as 50 degrees lower, and summertime attic temperatures that are 10 degrees or more cooler. TechPro TPO installations are inspected and certified by a Firestone factory inspector and then backed by a Firestone “system warranty” providing coverage for both material defects and TechPro installation workmanship for periods of up to 30 years. TPO is a recyclable material and is environmentally attractive by virtue of having a low calculated potential with regard to contributing to global climate change.
Many large local retail stores such as Home Depot, Lowes, Costco, Wal-Mart, Ikea, etc. are roofed with this material, as were 23 of 24 of the roofing projects completed for the 2010 Vancouver Winter Olympics. In total, nearly 3.o million square feet of TPO roofing was installed for Vancouver Olympic projects, including the one shown below left. The reason traditional torch-on roofing (which continues to account for over 70% of the BC market) was rejected for use on any of the Olympic projects was that it is an environmentally harmful project. As shown in the foregoing chart it is the worst available product in terms of contributing to global climate change. TPO was chosen for these projects due to its compatibility with the Games’ stated objective of “green” and sustainable construction of Olympic venues. Most recently, Firestone TPO was used to roof five of the new stadiums constructed for 2014 Brazilian World Cup.
2010 Winter Olympics TPO Roof 2014 Brazil World Cup Stadium TPO Roof
Examples of local area TechPro installed TPO roofs.
EPDM (Ethylene Propylene Diene Monomer) is a synthetic sheet rubber product that has the longest installed history in North America, dating to the 1960s. There are now approximately 25 billion square feet of EPDM installed in North America. Long-term studies have found that EPDM roofs tested 30 years after installation remain at or slightly below new product standards. EPDM is available as a black or white membrane. EPDM is a recyclable material and as demonstrated by the above chart offers the lowest contribution to the calculated “carbon neutral break even point” of between 15 and 20 years, the lowest of any of the available alternatives. With EPDM roofs providing services lives of up to twice and three times their carbon neutral break even points, EPDM roofs represent the most environmentally friendly roofing choice available today.TechPro EPDM installations are inspected and certified by a Firestone factory inspector and then backed by a Firestone “system warranty” providing coverage against both Firestone material defects and TechPro installation workmanship for periods of up to 30 years.
Below are examples of locally installed TechPro EPDM systems. These stratas have made an excellent decision to install EPDM to address their long-term water ponding issues. EPDM loves water!
PVC (Poly Vinyl Chloride) membranes were first introduced and installed as roofing material in Europe in the early 1960’s and began being installed in North America in the 1970’s. In Europe PVC remains the most commonly installed form of membrane roofing. PVC was almost exclusively used for the London 2012 Olympic Games, where it was mandated that the PVC installed be comprised of at least a 30% recycled content and any PVC material resulting from demolitions after the Game’s had to be fully recycled.
Duro-Last Roofing Inc. began producing its PVC roofing systems in the mid-1970s. One advantage of a TechPro installed Duro-Last PVC roof is that it can be tailor-made to a roof’s individual specifications at Duro-Last’s Grant’s Pass, Oregon fabrication plant. Factory fabrication minimizes waste and provides the highest possible amount of controlled environment seam welding. Duro-Last PVC is available in a wide range of colours beyond those shown. One important advantage of a Duro-Last PVC roof is that for strata and commercial installations Duro-Last’s “system warranty” uniquely includes coverage of “consequential damages”, i.e. any leak related damage to a building’s interior or to personal property is covered. While calculated as being more environmentally expensive to produce than either EPDM or TPO, Duro-Last roofs provide long service lives and Duro-Last has a well established recycling program.
Examples of Duro-Last PVC roofs installed by TechPro.