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Roofing Selection Goes Life-Cycle
OTHER PARTS OF THIS ARTICLEPt. 1: This Page
As a buzzword and as a concept, “environmentally responsible” has proven to have some staying power. Employed since the 1970s to describe increases in efficiencies or decreases in natural resource consumption, use of the phrase has reached a new crescendo during the last half decade.
Today, another phrase, “life-cycle assessment” (LCA), has crept into the lexicon. Usually meant as a method for determining long-term costs and payback, LCAs are increasingly being used to aid facility executives in determining the environmental results of their roofing choices. But that’s where things get complicated — there is a multitude of ways to slice environmental impact.
“There’s only one denomination of money, but so many ways to count environmental effects,” says Jim Hoff, president of Tegnos Research, Inc.
Cost metrics are still the most important criteria for determining product choices. Even high-performing roofing choices are usually measured only by return on investment.
That’s not a bad method. Though justification in real dollar terms will be mandated by C-suite management, it does not give a full picture of the benefits of conducting an LCA when both financial and environmental facets are considered. After all, the intangible benefits — such as increased public relations opportunities from green choices — are not immediately quantifiable. When properly leveraged, environmental LCAs can provide significant financial benefits for organizations.
The Center for Environmental Innovation in Roofing (CEIR) is dedicated to helping facility executives determine the full scope of benefits when choosing environmentally sound roofing choices.
“We want to advance the dialogue of possibility,” says CEIR’s executive director, Craig Silvertooth. “We try to reinforce the decision-making process and encourage consideration of the life cycle at a global level.”
How, then, to proceed? An environmental LCA begins with the recognition that all the environmental impacts of a roof choice — from cradle to grave — should be considered.
“Quantification of all building phases is important in life cycle assessments, especially for the construction phase, which is often disregarded,” says H. Scott Matthews of Carnegie-Mellon University’s Green Design Institute, and a widely published author on the topic of Environmental Input-Output LCAs. He has also worked in the construction industry.
Both Hoff and Matthews advocate an ambitious, holistic view, taking into account previously unconsidered information, such as fuel-use estimates, global warming potential and emissions, including particulates, carbon monoxide and volatile organic compounds.
“The I-O-based hybrid LCA tool presents updated, revised, and more comprehensive estimates of the environmental impacts of construction projects than previous and existing construction LCAs,” Matthews says.
In real world terms, that means facility executives need to dig a little deeper to consider their roof’s environmental impacts.
Hoff gives the example of using locally assembled components: “It’s great to buy local, but if the components originated from an overseas source, the cost and fuel used to get them to your area outweigh the benefits of sourcing local assembly.”
He also says that it’s important to consider integration and re-use of construction waste where possible to avoid putting it unnecessarily into landfills.
The bottom line, he says, is to recognize that LCAs should consider every aspect of roofing construction.
“Consider the origin of the raw materials, the energy to produce and transport those components,” Hoff says. “And don’t make decisions that are too narrowly focused.”
As carbon cap-and-trade concepts gain ground, so too are other environmentally minded declarations.
European nations are considering Environmental Product Declarations, which specify the origins, transport requirements, and supply chain of any given product.
The expectations of several international organizations include the desire to tabulate LCA-based information in the supply chain and to compare different Environmental Product Declarations.
For facility executives, this means an opportunity to weigh the efficiency of a given roofing system in concert with the environmental costs of sourcing, supplying and transporting materials before construction ever begins. But a few considerations help identify priorities.
First, determine what’s important to your organization. “Focus on local environmental issues,” says Hoff.
Organizations in major metropolitan areas might want to think about how the life cycle of their roofing choices affects the local urban heat island effect, in addition to energy performance.
Choosing recycled products is good, says Mark Gaulin, chief operating officer of Tecta America, provided that the choice of materials doesn’t degrade roofing performance. “You still need high-quality products,” he says.
Industry experts also advocate looking beyond a mere approval sticker. Many green advocates applaud the U.S. Green Building Council and its LEED rating system for taking a landmark position and furthering the advocacy of environmental awareness. Though LEED does have its detractors and there are some project teams that use LEED in ways it wasn’t intended, overall LEED is often recognized as the de facto green building standard.
“At some point, this will just be the way you build buildings,” Gaulin says. “You need to design the building correctly, whether it has a sticker from LEED or not.”
And don’t focus on environmental assessments to the point of obscuring common sense.
“Stick with good design disciplines,” says Gaulin. Ultimately, Gaulin’s warning to consider good design boils down to durability. “A lot of people don’t consider the longevity,” he says.
Durability and Material Re-use
Many within the industry agree that facility executives should aim for longevity.
“You have to think about durability,” says Silvertooth. “Using high-efficiency roofs without known longevity is a tad foolish. Replacing systems that fail prematurely doesn’t do a lot of good for the environment.”
Construction waste and roofing tear-offs are significant contributors to landfill disposal. Consequently, many industry analysts recommend choosing highly durable roofing systems or migrating to systems that are re-usable in other wall or roof systems after the original roof system requires replacement.
“Ultimately, you want to look for durability and high-performance over the long term,” says Silvertooth.
Gaulin uses specific examples, saying that building owners should choose insulation that won’t degrade or absorb moisture over time. Choose products that have a second or third life, such as extruded insulation and polyisos.
This is where both money and environmentalism put rubber to the road. “Say you choose a system that only lasts 17 years,” Gaulin says, “But for 25 or 30 percent more, you get a system that lasts for at least 30 years.”
For nearly twice the roof system life, facility executives would pay a 25 percent premium to avoid tear-off disruptions, disposal costs, and price of an all-new roofing system. That’s the cost factor. The environmental factor avoids premature disposals.
“Filling up landfills is not a practical way of doing things,” says Gaulin.
Tim Pennigar, project manager of structural systems for Duke University Health System, used the concept of adaptive re-use during a 2007 roof replacement. Pennigar’s team managed to salvage 90 percent of the insulation, diverting 718 tons of solid waste. Salvaged materials from this effort included 296,000 board feet of XPS insulation — all of which has been reused in new roofing construction on two Duke buildings.
The quality and durability of a product is one of the first things Pennigar determines, especially a product’s role in adaptive re-use.
“A green roofing system that is compromised and only lasts a couple of years is not a green system,” Hoff says.
The biggest potential for adaptive re-use is with insulation, say experts. Simply put, roofing materials typically do not last as long as other materials in the building envelope — with the possible exception of insulation, assuming there’s no degradation of R-value from wetness or UV exposure.
Hoff believes one focus of roof system manufacturers in the coming years will be determining how the system parts can be disassembled for effective re-use in wall systems or roofing.
Hoff also says facility executives should consider the needs of the entire structure when conducting an LCA for roofing projects. For example, there are tax deductions in EPAct 2005 for commercial buildings that meet EPAct requirements. An energy efficient roof can help a building meet those requirements, but the exterior should be looked at as a whole. A roof can also help attain LEED credits in ways that are not immediately obvious. For example, well-placed skylights can reduce interior lighting needs and improve productivity.
Hoff suggests building into the LCA process a strategy that includes examination of the walls and roof plane.
Greater opportunities for environmental responsibility with LCAs are on the horizon.
Silvertooth says the advent of nanotechnology and PV panels that are built into roof systems are important developments for facility executives interested in more environmentally responsible roofing. The semiconductor technology would allow facility executives to simultaneously protect their roof and gather electricity to supplant — or give back to — their draw upon the grid.
Another roofing option gaining momentum is the green — or garden — roof. CEIR is currently funding research on vegetated roofs to quantify and establish an R-value for vegetated roofing.
Right now, says Silvertooth, regional studies are being done. CEIR hopes to answer questions that plague owners depending upon their location:
- How much media is needed up there?
- What kind of vegetation goes on the roof?
- What about leaks in the membranes?
- What insulative paybacks do these systems have?
- What fire and wind ratings are needed on vegetated roofs? (Silvertooth says that plants that dry out and die may be a fire hazard.)
For facility executives conducting their first LCAs for roofing products, experts have a few last tips. Don’t focus narrowly on key factors — address impacts that affect your organization. If public relations opportunities are welcomed by senior management and the rest of the organization, consider using a roofing LCA to leverage environmental news.
Life-cycle assessments (LCAs) should examine the potential environmental impacts of product systems or services at all stages in their life cycle — from extraction of resources, through the production and use of the product to reuse, recycling or final disposal.
Several free Web-based tools are available from life-cycle.org, and eiolca.net, but the basic framework is fairly simple and can help determine if a full-bore assessment makes sense for an organization.
Headquartered in Washington, D.C., the Center for Environmental Innovation in Roofing (CEIR) acts as a forum to draw together the roofing industry in the common cause of promoting the knowledge base, development and use of environmentally responsible, high-performance roof systems. Its goals include:
Click here for more information about the Center, or contact Craig Silvertooth, the Center’s executive director, at (866) 928-CEIR.