Roof/Ceiling R-Value Requirement
I’m trying to understand what level of insulation is required in my roof/ceiling based on the 2012 energy code for Zone 5. Based on the tables I’ve looked at, R-49 looks like the basic requirement, but I’m trying to figure out if I can step down to R-38 or even R-30 based on what I plan on doing? Here’s a few of the details:
– I will have no attic (100% vaulted ceiling)
– There will be no cavity insulation between the rafters. All insulation will sit on the structural roof deck and be continuous.
– The roof insulation will be lapped over the wall insulation (lapped over both interior wall insulation and exterior wall insulation).
GBA Detail Library
A collection of one thousand construction details organized by climate and house part