Just looking for some feedback. I have a set of plans here showing a 2x12 rafter roof assembly insulated with fiberglass R-38 batts. According to the IECC, (all other sections of the code considered) The prescriptive table calls for R-49 here (insulation r-value only). However, if you go to Section 402.1.3 U-factor alternative (entire roof assembly u-value) and work the numbers for this same assembly, R-38 will work. Am I wrong in saying that even though the prescriptive requirement is R-49, The U-factor from Table 402.1.3 of 0.026 ( inverse of R-38 + the R-values of the other components) for a U-value of equal to or less than 0.026 will suffice?
My post here sounds more confusing than it really is. apologies in advance to those who attemt to decipher it. :cowboy
My post here sounds more confusing than it really is. apologies in advance to those who attemt to decipher it. :cowboy