My wife and I purchased a contemporary house almost 2 years ago. It has 2x8 framing for rafters with cathedral ceilings everywhere. The problem is we only have r-19 insulation. I am looking for a way to add as much r value as possible without removing the drywall.
First solution would be: to tear of sheathing and have a company intall spray foam insulation, very expensive.
Second solution: leave the sheathing on and install 2-3 inch foamboard, with new layer of 7/16" osb and roofing material over that.
My question is has anyone ever encountered anything like this, if so what is the best solution?