I'm getting my siding replaced and noticed that my walls currently only have foam board, without any OSB. The plan is to take out the foam board, replace it with OSB, and then add foam board back on top. The siding company mentioned that I won't need a house wrap because the foam board being used (polyiso insulation) has a built-in barrier. I'm in Michigan and just want to make sure this plan is okay or if I'm missing something important.
2 Answers
Their approach is actually pretty solid! While it might not be my first choice for a moisture barrier, polyiso insulation can definitely work well to keep moisture in check. If you can, ask for foil-faced foam instead; it might give you an extra boost in terms of energy efficiency and moisture control!
It sounds like a good plan, but just be aware that homes have been built with just foam sheeting and no plywood or OSB for some time, especially in spec homes. They usually use diagonal bracing in the corners to keep the structure stable, which should be fine if it was done right. Just make sure your contractor knows what they're doing!
Exactly! Just check if they have included that bracing in your walls.