I've already added 2" to the wall thickness in this plan; if I go much thicker it'll start to look stupid at the doors/windows. I don't really want to give up the rockwool and fill the cavity with foam because I'll lose the sound insulation (though R42 is pretty spiffy lol)
I think you are safe just adding them, I am sure there is some scientific calculation but.
I saw something the other day, where they suggested 2 layers of 1 1/2 foam on the outside in different orientations. It allows you to move the buck for the windows and doors out 1 1/2" giving you better insulation around the doors and windows.
Found it.
I saw something the other day, where they suggested 2 layers of 1 1/2 foam on the outside in different orientations. It allows you to move the buck for the windows and doors out 1 1/2" giving you better insulation around the doors and windows.
Found it.
