Although precise definitions still are evolving, HPR protective umbrellas share five important characteristics that make them energy efficient, environmentally friendly, cost effective, leak proof, reliable and long-lasting. Think of them as the “Five E’s.”
- 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 a roof is, it still has to protect the building in all types of weather.
- Economics: HPR systems must be cost effective based on initial cost and, more importantly, life-cycle cost. Roof systems must make economic sense to building owners and managers before they will become widely accepted.
- Energy: HPR systems help reduce energy consumption and improve the energy efficiency of the building envelope. This is a primary benefit of cool roofing and a critical aspect of sustainability.
- Environment: HPR systems help reduce the overall impact on the external environment while creating and maintaining a healthy productive indoor environment. This is the primary objective of sustainable roofing, which also focuses on energy efficiency and endurance.
- Engineering: Smart engineering and design are the great enablers of HPR systems and the other E’s. Engineering impacts everything from intelligent design and installation to life-cycle costs and long-term performance in all weather conditions.
There are several key questions to ask roofing contractors and/or manufacturer’s represent- atives to determine whether a roof system is high performance. The following should be asked to ensure your prospective roof system meets each of the five E’s:
1. What is the range of durability for this type of roof system?
The durability of roof systems varies widely depending on the manufacturer, competence of the roofing contractor, climate and other factors. This is why roofing expert Carl Cash, principal of Simpson Gumpertz & Heger Inc., Waltham, Mass., suggests building owners consider the durability range of various systems – a better indication of how long the best roof systems in each category can be expected to last. For more information, read Cash’s book, Roofing Failures.
2. In terms of maintenance and repair, how often, how much and how easy?
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 a life-cycle cost analysis available that includes all installation costs, estimated maintenance/repair costs and potential energy savings during the life of the roof? In 2004 a 20-year life-cycle-cost comparison was prepared by independent Midwest roofing contractors; the study was sponsored by Duro-Last Roofing Inc., Saginaw, Mich. It compared the life-cycle costs of a reflective polyvinylchloride single-ply with the averages for a black ethylene propylene diene terpolymer and built-up roof system for a fully warranted, 50,000-square-foot reroof in the Midwest.
Software programs, how-to books and guidelines are available to assist in completing life-cycle cost analyses for commercial roof systems. Building owners also should ask their roofing contractors to provide an analysis for each system under consideration. Many manufacturers currently provide this information.
1. Does the roof meet criteria set by EPA’s Energy Star Reflective Roof Products Program?
Visit www.energystar.gov/index.cfm?c=roof_ prods.pr_roof_products to determine whether a roof system you’re considering 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 also can use EPA’s online calculator (roofcalc.cadmusdev.com/) to determine potential energy savings for your building. An energy-efficient building using an HPR system is a step toward mitigating the urban-heat-island effect.
2. Does the roof meet ASHRAE Standard 90.1?
If it does, you may be eligible for tax deductions. If it doesn’t, it isn’t an HPR system.
3. Does the roof earn points toward USGBC LEED credits?
A building can receive one point toward LEED certification if its roof system meets the standards under Sustainable Sites Credit 7.2 – Heat Island Effect: Roof. A combination of design characteristics, including roofs, can earn points in several credit categories, including Stormwater Management, Minimum Energy Performance, Renewable Energy and Construction Waste Management.
4. 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.
5. Is the roofing material recyclable?
Oak Ridge National Laboratory, Oak Ridge, Tenn., recently estimated 9 to 10 million tons (8 to 9 million metric tons) of nonrecyclable roofing waste is sent to U.S. landfills every year.
6. Does the roof system help create a comfortable, healthy, productive environment inside buildings?
IAQ is an increasingly important issue regarding health and improved productivity of building occupants. Cool, vegetated and, perhaps, solar-integrated HPR systems moderate indoor temperatures even in buildings without air conditioning. Vented roof systems can help reduce moisture and mold while relieving positive air pressure, allowing buildings to “breathe.”
1. Is this a fully integrated roof 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 other interactive components. Likewise, a high-performance roof is a fully integrated system that protects the building from the elements and actually enhances the performance of other building components, such as thermal insulation and the HVAC system. Check the warranty to ensure the entire roof system is covered.
2. Does the manufacturer use premium components and state-of-the-art manufacturing processes to enhance energy, environmental, endurance and economic performances?
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 roof system?
Prefabricated roof 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 factory conditions.
Originally published on Kelly Roofing website.
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