NRCA recently published an Industry Issue Update for members that analyzed energy savings and cost paybacks stemming from energy code-mandated increases in R-values for low-slope roof assemblies. The findings and NRCA's conclusions are summarized here.
Energy code requirements
The building envelope thermal requirements contained in the International Energy Conservation Code,® 2012 Edition (IECC 2012) provide prescriptive minimum thermal insulation (R-value) requirements for building envelope components, including roof assemblies.
Comparing IECC 2012's values to those of the International Energy Conservation Code, 2009 Edition (IECC 2009) reveals minimum required R-values have increased from R-5 to R-10 depending on specific climate zones and building (roof) assembly configurations.