I am building a house in South Dakota. The walls are sheathed with 7/16 OSB and will be covered with 3/4 R4 T&G Pink foam board. Finally, 8″ Hardie plank over that.
Does it make any difference if the Tyvek is over or under the foam board? It is much easier to attach to the OSB and put the foam over the top. The wind will not rip it off. Any thoughts would be great.
Replies
A couple of things seem counter intuitive here.
Foam board is a pretty good VP, so why would you want something that is suppose to allow water vapor in the wall out beneath it" You are in a predomently heating climate, so you want your VP inside the wall.
Do a search for the Mooney Wall here if you are trying to create a thermal break.
I'm not a Hardie siding installer, but trying to hang any siding over foam board could be a problem, with over driving nails and getting waves in the material. I just don't know, but someone here with Hardie expereince will chime in shortly.
Take a look at http://www.buildingscience.org fora reccomended wall assembly for your climate.
Dave