Refectivity/Emissivity
Durability
Proper Membrane Selection
Proper Installation
Maintenance
These two elements of a "cool roof"are the two attributes that get the most ink. Yes, a high solar reflectance, or albedo, and infrared emittance (the proper scientific terms) will result in a cooler facility, cooler city, and cooler planet. To qualify as a cool roof, experts suggest picking a membrane with a reflectance of at least .65 and emittance of at least .85.
What's the point of claiming your roof is high-performance if you have to replace it long before its expected lifespan. Here's a loosely guarded secret: Short-term, cheap roofs are NOT high-performance. Indeed, durability is perhaps the most critical element in a high-performance roof system. Be sure to choose a roof from a trusted manufacturer that doesn't play games with its warranty. And find out if the roof can be recycled at the end of its useful life — while not necessarily a component of high-performance, a roof's recyclability certainly enhances its sustainability.
Single-ply membranes are a good high- performance roofing option for many building types and situation. A few examples include when re-covering an existing membrane, when the building is wide open with large expanses of uninterrupted roof area, when installing a green roof on top, or when the roof needs to be installed in cold weather. But it's always critical to follow manufacturers recommendations. Matching a good membrane to a suitable roof is an absolutely essential step to achieving a high-performance roof.
Perhaps no other factor can have a more detrimental effect on the performance of a roof than poor installation. Get at least three bids from qualified contractors that are approved by the manufacturer of the membrane you're interested in. Visit the sites of their other jobs and talk to those facility managers about their experience. Understand that the manufacturer's warranty usually only covers material defects, so find a contractor that will offer a solid workmanship warranty, as well. And monitor the job - make sure the contractor sends an experienced foreman and completes the job on time but without cutting corners.
A high-performance roof is not a set-it-and-forget-it proposition. Far from it. To get the most out of a roof, it requires regular attention. Experts suggest at least twice-yearly inspections, in the spring and fall. To continue to maximize a cool roof's efficiency, periodic cleanings may be necessary as well. One of the keys to maintaining a high-performance roof is to record when inspections and maintenance have been performed - treat the roof like you would any other facility asset.
Long gone are the days when roofing was merely roofing, designed to turn back rain and snow and nothing more. Increasingly, all building components, including roofing, are considered for their environmental and long-term performance characteristics.
Now, the performance of a roof can be measured in terms of... read more
