In keeping with the sustainable design principle, metal roofs consist of roughly 25 percent recycled content, and at the end of their useful lives are nearly 95% recyclable. Most other cool roof systems cannot be recycled, and will eventually take up space in solid-waste landfills.
By specifying a retrofit cool metal roof system, many leaky flat roofs can be left in place, reducing the inconvenience to the building owner by not disrupting their day-to-day business activities. This also reduces the need to landfill the old flat built-up roof since it can usually be covered with the metal roof. The new retrofit metal roof, including any framing to add a new roof slope, will weigh a mere 2 – 3 lbs per square foot. The new roof system may not require additional insulation to be installed due to the fact that the existing roof still contains it’s insulation. If it is necessary to add insulation to the system, it can easily be done within the attic space created by the increased slope of the new metal roof. If necessary, the attic can also be vented to help dry out the old substrate.
Whether the project goals include reducing energy costs for the building owner, reducing peak energy-demand during hot weather, or environmentally responsible roofing solutions, cool metal roofs make sense. While it is important to adhere to the legislative requirements, it is equally important to realize that a cool roof system that doesn’t stay clean will not remain cool for long. Remember to investigate products that are advertised as cool roof solutions to be sure they have 3-year aged test values that prove they can retain their reflectivity reflectance and emissivity emittance for the life of the roof. Specifying cool roof materials is not just about meeting code requirements - it is about providing long-term solutions for the future.