Share 'What is the R Value of a 2x6 dense packed cellulose wall?'

I am reviewing the requirements of the new Maine Uniform Building and Energy Code that goes into effect 12/1/2010.  The required R value for a wood framed wall is R20. If I assume the Dense Packed Cellulose has an R value of 3.4 per inch and a 2x6 is really only 5.5" deep, then 5.5" of cellulose is only R18.7 which doesn't quite meet the standard.I could put in R21 fiberglass and meet the standar…