I am looking for some ideas on how to insulate a ceiling in a log cabin. There is some insulation on the top side (R15) but I am thinking of adding insulation on the underside. Because the house is over 80 years old, I'd like to keep the appearance and also keep the weight on the ceiling down. I am thinking of having spray foam insulation installed and then installing ceder boards on top of it. I would probably have to install 2X6 ceder boards beside the balsam rafters to get a straight surface to attach the cedar boards to .
Thanks for the suggestion, but I have already installed a upper roof with special 2" (R15) fibreboard insulation. (Most people are not familiar with this stuff. It's like a hard fibreglass-type of 4X8 sheet..usually used in flat roof construction under tar.) On top of the roof is a Tough-Lok steel roof (50 yr warantee) that costs an arm and a leg but looks like cedar shake.