Frost buildup in wall cavity in unfinished house
Happy New year. My wife and I are totally rebuilding our house, starting from the foundation up. We are living in it while completing interior work. We live at 1600 feet in central
The walls are 2×6 with zip system sheathing with all joints carefully taped. The house feels very airtight. R23 roxul batts. Most of the insulation is currently exposed. I’ve periodically pulled the insulation back to check for moisture and never found any. It’s been unusually cold this week. Today it is -11F outside, 60 inside with an interior humidity of 35%. I pulled some insulation back and found frost behind every place I checked. Not just near possible leaks, but everywhere. It is a consistent 1/8″ covering, and not melting or dripping out anywhere. The roxul fits very tightly, and this surprised me.
I’m assuming having tight sheetrock would help with this, but I’m not sure if this indicates a problem. I do have sheetrock in the kitchen and bathroom, but no way to check those cavities. All of the exterior receptacles are in the draft proof boxes.
I wasn’t planning on a vapor barrier, and I still don’t think I want one. My thinking was to allow any moisture that might build up in the walls a way to escape.
I’m just not sure if I need to rethink my design or Not. I’ve never lived in a house with exposed insulation, so I have nothing to compare to.
Do you guys think this is normal for my situation or indicative of a problem?
Thank you for any thoughts on the matter.