ASHRAE announced an increase to the minimum required prescriptive R-value for roof and wall insulation levels

The American Society of Heating, Refrigeration and Air-Conditioning Engineers announced an increase to the minimum required prescriptive R-value (resistance to heat flow) for roof and wall insulation levels in Standard 90.1, the national model energy code for commercial buildings. The above-deck roof insulation requirements currently at R-15 go to R-20 - an increase of 33 percent - in every climate zone in the United States. Similar increases were approved for walls.