We have one bedroom that was always freezing cold as well as the drywall was heavily damaged from the previous owners. We decided to replace the drywall, and at the same time, get to the bottom of the freezing cold situation. FYI, this particular room does have 3 exterior walls.
So we removed the insulation, intending on sealing all the cracks and then replacing with new, higher value insulation (not much of a jump, what was in there was R-11 and we can only go up to R-13 since it is a 2x4 wall).
What we were surprised to find was that 70% of the room has just a 3/4 inch piece of styrofoam between the vinyl siding and the room itself. There is only plywood on the corners, about 5 foot in on each side. The rest is all styrofoam. Is this normal to find? The styrofoam is not blue on the one side, it is all white and not very thick. It's really not much stronger than a styrofoam cup, although it is is about 3/4 ... maybe 1 inch thick.
We are not quite sure how to proceed from here. Is this typical and to code the way it is? Would sealing all the cracks and then putting new insulation help at all where the styrofoam is, or do we need to replace this stuff? Surely our whole house is probably built this way, and we really haven't seen much energy issues other than this one room.
Any advice/help would be much appreciated!