Several years ago while working on a Colorado shopping mall I was surprised to see the Design Development drawings I was reviewing indicated insulation at the low-sloped roofing assembly as a mere R-11. The climatein this part of Colorado, as with most of Colorado, is cold—really cold. Way colder than the winters I am used to in the Pacific Northwest. In my neck of the woods, at that time, the R-value requirement for roofing assemblies was nearly three times what I was seeing in the shopping mall drawings. I assumed a huge error had been made, and I assumed incorrectly. At that time, R-11 was all that was required to meet the energy code requirements.
Fast forward to 2012, are things any different in Colorado? Yes, they are! Almost every state in the US has adopted (including Colorado), in some form or another, the International Energy Conservation Code. For a snapshot of Statewide International Code adoption, go to www.iccsafe.org/gr/Documents/stateadoptions.pdf.