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The Next Stage in Design/Cost Standards for Commercial Roofing
By Drew Ballensky
“Will this roofing system help reduce my electric bill?”
“Is this a sustainable, environmentally friendly roofing system?”
As anyone involved in the North American commercial roofing industry knows, these are two questions that building owners and managers are asking with increasing regularity. Most commercial roofing buyers still want to know about cost and performance first, but as both “cool” and “sustainable” roofing continue to gain marketplace acceptance, they are driving significant change in market dynamics, roof system design and manufacture, product innovation, industry initiatives, selection priorities, building codes and legislation.
Cool and sustainable roofing are also sparking a considerable degree of discussion, commotion and controversy due to their ongoing impact on the commercial roofing industry. The very definitions of “cost” and “performance” are changing as they incorporate concepts such as life-cycle costs (LCC), life-cycle analysis (LCA), energy efficiency and sustainable performance.
It has been about ten years since cool and sustainable roofing emerged as separate, but closely related, commercial roofing industry trends. Today, both concepts have been embraced by a host of industry associations and government agencies, many of which are striving to define the “roofs of the future.” As industry groups continue to develop universal definitions and objectives for cool and sustainable roofing, government agencies at the federal, state and local level are implementing more standards, regulations and incentives to encourage, or mandate, the use of energy-efficient and/or sustainable roofing systems.
The Emerging High-Performance Trend
These actions, combined with simple but powerful economic factors, are creating increased demand for a new class of High-Performance Roofing (HPR) systems that can satisfy traditional performance criteria – such as installed cost, performance and longevity as well as newer criteria – such as life-cycle costs, energy efficiency, and preservation of the environment.
High-Performance Roofing is part of a larger trend toward High-Performance Buildings, which is especially strong among builders and managers involved in the construction and renovation of school systems and government facilities. The Department of Energy (DOE) has established a High-Performance Building initiative that focuses on promoting energy-efficiency nationwide. The DOE defines the benefits and objectives of High-Performance Buildings and “whole-building design” as:
• Energy consumption reductions of 50 percent or more
• Reduced maintenance and capital costs
• Reduced environmental impact
• Increased occupant comfort and health
• Increased employee productivity
High-Performance Roofing systems can contribute significantly toward all of these High-Performance Building objectives. As part of a High-Performance Building, an HPR system acts as a vital, performance-enhancing umbrella that protects the facility from the elements, enhances the performance of other building components, enables uninterrupted operations, and contributes to the health and performance of occupants.
And, contrary to some popular myths, HPR systems that are cool and sustainable do not necessarily involve additional costs. In fact, an essential criterion of High-Performance Roofing systems is that they reduce life-cycle costs (LCC) significantly without substantial tradeoffs in performance or longevity.
The Five E’s of High-Performance Roofing
How can facility managers and building owners tell if a roofing system is “high-performance?” While precise definitions are still evolving, HPR protective umbrellas have five important, closely related attributes that make them cost-effective, leak-proof, reliable, long-lasting, energy efficient and environmentally friendly. An easy way to remember these five attributes is to think of them as the “Five E’s” for making informed, cost-effective roofing choices:
• Energy: HPR systems help reduce energy consumption and improve the energy efficiency of the building envelope. This is a primary benefit of cool roofing, but reduced energy use also contributes to a better environment.
• Environment: HPR systems help reduce the overall impact on the external environment while also creating and maintaining a healthy, productive indoor environment. This is the primary objective of green, or sustainable roofing, which also places a premium on energy efficiency and endurance.
• Economics: HPR systems must be cost-effective based on both initial cost and, more importantly, the entire life cycle cost. No roofing system will gain wide acceptance if it does not make economic sense to building owners and managers.
• Endurance: HPR systems must meet, or exceed, traditional performance standards in terms of longevity, all-weather reliability, water absorption, wind and fire resistance, low-maintenance and simple repair. No matter how “cool” or “green” a roof is, it still has to protect the building in all types of weather – a reality that is sometimes neglected in sustainability discussions.
• Engineering: Smart engineering and design are the great enablers of High-Performance Roofing systems, and all four of the other E’s. Engineering impacts everything from intelligent design and installation to life-cycle costs and long-term performance in all weather conditions.
The HPR Checklist
No doubt all of these high-performance roofing characteristics sound great … in theory! But what about the real world? How can facility managers and building owners tell if a roofing system meets all, or at least some, of the five HPR criteria? There are several key questions to ask your roofing contractor and/or manufacturer’s representative that can help determine if a roofing system is “high performance.” Here are a few of the key checklist topics for each of the five E’s. (For a comprehensive HPR checklist, visit www.duro-last.com/coolzone.)
1. Is a life-cycle cost (LCC) analysis available that includes all installation costs, estimated maintenance/repair and potential energy savings over the life of the roof? In 2004, a 20-year LCC comparison was prepared with the help of independent Midwest roofing contractors (above). This LCC compares the life-cycle costs of a reflective PVC single-ply with black EPDM and BUR systems for a fully-warranted, 50,000-square-foot re-roof in the Midwest. While actual costs will vary depending on each situation, note the differences between installed costs and life cycle costs.
1. Does the roof meet criteria set by the Environmental Protection Agency’s ENERGY STAR® Roofing Products Program? Visit www.energystar.com to see if the roofing system is listed. If it isn’t there, the roof material probably does not meet the ENERGY STAR minimum standard that requires low-slope roof products to have an initial reflectance of at least 65 percent, and a reflectance of at least 50 percent after three years of weathering. You can also use their online calculator to determine potential energy savings for your building. Energy efficiency also reduces pollution by mitigating the urban heat island effect (visit http://eandE.LBL.gov/heatisland).
2. Does the roof meet ASHRAE Standard 90.1? The American Society of Heating, Refrigeration and Air Conditioning established Standard 90.1 as a minimum requirement for energy-efficient building design. Adopted by the federal government in 1994, it sets the roof reflectance minimum for government facilities at 70 percent and the minimum emittance level at 75 percent. Last year President Bush signed legislation offering tax incentives to buildings that exceed Standard 90.1.
3. Does the roofing system exceed local building codes for minimum thermal resistance (R-values)? Insulation is an important component of all roofing systems – reducing heat loss by convection in winter months, and controlling heat gain through conduction in the summer. Lawrence Berkeley National Laboratory recently determined that increasing the R-value of a roofing system in Los Angeles from R-9 to R-15 would reduce annual energy costs by $2,500, and lower carbon dioxide emissions by thousands of pounds.
1. Does the roof earn points toward USGBC LEED® credits? The U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED®) voluntary rating system is an increasingly popular means for helping building owners determine environmental performance (www.usgbc.org). Buildings can be credited one point toward LEED® certification if their roofing system meets the standards under Sustainable Sites Credit 7.2: Heat Island Effect: Roof. In many other sub-categories, a combination of design characteristics that may include roofs can earn points, including: Storm Water Management, Minimum Energy Performance, Renewable Energy, and Construction Waste Management.
2. Is a roof tear-off required? Certain lightweight HPR systems can be installed, fully-warranted, directly over the existing roof to reduce installation and disposal costs while slowing the rate of landfill buildup.
3. Is the roofing material recyclable? Oak Ridge National Laboratories recently estimated that nine to ten million tons of non-recyclable roofing waste is sent to U.S. landfills every year. Ask if the roofing manufacturer has a recycling program.
4. Does the roof system help create a comfortable, healthy, productive environment inside buildings, where many people spend most of their days? Indoor air quality is an increasingly important issue in terms of both health and improved productivity of building occupants. Cool, garden and perhaps solar-integrated HPR systems help to moderate indoor temperatures, even in buildings without air conditioning. Vented roofing systems can help reduce moisture and mold while relieving positive air pressure, allowing buildings to “breathe.”
1. What is the range of durability for this type of roofing system? The durability of any type of roofing system can vary widely depending on the manufacturer, competence of the roofing contractor, climate and other factors. This is why roofing expert Carl Cash suggests that building owners consider the durability range of various systems, a better indication of how long the best roofing systems in each category can be expected to last. By this measure, five types of roofing systems have a high-end range of service longer than 20 years: PVC thermoplastic single-ply, asphalt-glass fiber BUR, SBS polymer-modified asphalt, EPDM thermoset single-ply, and asphalt-organic felt BUR.
2. In terms of maintenance and repair: How often? How much? How easy? Local references? Every year of useful service free of major maintenance and repair work reduces the life-cycle cost of any roof. Be sure to ask about a roof system’s recommended annual maintenance procedures and costs.
3. How long, and how good, is the warranty? Warranties reveal many strengths and weaknesses. Small print and exclusions can highlight potential problem areas, such as ponding water, consequential damages, and repair/replacement procedures in case of failure. Don’t be fooled by the length of a warranty – read the fine print for hidden costs and exclusions.
1. Is this a fully integrated roofing system that provides watertight performance while enhancing the performance of other building components? A high-performance building is a complete system that includes electrical, flooring, HVAC, roofing, doors, windows, insulation and many other interactive components. Likewise, a high-performance roof is a fully integrated system that not only protects the building from the elements, but actually enhances the performance of other building components, such as thermal insulation and the heating-ventilating-air conditioning (HVAC) system. Check the warranty to make sure the entire roofing system is covered.
2. Does the manufacturer use premium components and state-of-the-art manufacturing processes to enhance energy, environmental, endurance and economic performance? Specification of premium materials enhances a wide range of performance criteria, including reflectivity, emittance, ultraviolet radiation resistance, water resistance, fire and wind resistance, tensile strength, thermal expansion and dynamic puncture resistance. Environmental performance is enhanced by incorporating materials that are recyclable and reduce the total embedded energy index, and by using closed-loop manufacturing processes that minimize waste and toxic emissions.
3. Is this a custom prefabricated roofing system? Prefabricated roofing systems designed to fit each roof reduce installation time and labor costs, virtually eliminate roof membrane scrap, and minimize job-site errors by producing seams and other critical components under quality-controlled conditions in the factory.
The High-Performance Future is Here
Growing demand for cool and sustainable roofing is creating market demand and government regulations for High-Performance Roofing systems that provide optimal functionality with respect to energy, environment, endurance and economics. This trend ties in directly with the growing demand for energy-efficient, environmentally friendly High-Performance Buildings nationwide. The high-performance future is already here. The design/cost challenge is to specify high-performance roofing systems, and to continue improving every aspect of innovative, HPR systems and high-performance buildings.
About the Author: Drew Ballensky is general manager of Duro-Last Roofing, Inc.’s Sigourney, Iowa, plant and spokesman for the Duro-Last Cool-Zone high-performance roofing system.