I have a typical raised ranch built in 1963. I recently built an addition which is well insulated and sided with natural shingles. I need to do something about the exterior of the original house as it is painted green. I also need to insulate it. I could sand the shingles and blow in insulation but I am concerned that that insulation will settle. The other option I have considered is to remove the old shingles (too bad 'cause they are in good shape)put foam sheet insulation under new natural shingles. Which option do you think would be most efficient?
First things first, insulating behind the siding is important, but not as important as insulating the ceiling of the upper most floor. If you do not have 19-22 inches of insulation there, you need to add that first as that will deliver far, far more energy savings than insulating the walls.
Same goes for floors, if they are over unheated spaces.
Now, as for the walls, blown in insulation is a good option and can be done professionally with little risk of settlement being an issue. Blown in insulation is put in under a skylight pressure to account for settlement and installers can use infrared camera to easily check for areas that may have been missed.