Hi,

We have a 1,680 sq/ft house built in 1955. Most of the walls are CMU with a 2 older stud wall additions. The house is empty and old plaster/lathe walls are gone. The roof is a GAF Fleece back TPO with Olybond spray foam adhesive. Plans are to frame new interior partition walls, drop ceiling over interior hallway for MEP, new windows, 2.5 ton split for most of house, mini split for the 2 small room additions due to LVL beams separating certain areas of the 2×8 roof. My question is what is best option for insulation cost wise? The roof is close to a 2/12, 8′ eaves and 10′ ridge, the ceiling will be drywalled, CMU walls will be INSOFAST R10 foam and drywalled, rest of stud walls R19, I was thinking R20-R-25 plastic faced if I can find it for the ceilings. Any better ideas cost wise that is widely available? Thank you for any information!