This article first appeared in the 200802
issue of BD+C.
For the first time in nearly two decades, ASHRAE has increased the minimum required prescriptive R-value (resistance to heat flow) in ASHRAE Standard 90.1 to R-20 for above-deck roof insulation, from the current R-15 level—a 33% increase. Similar increases were approved for walls. For more, visit www.ashrae.org.
