Sauna inside home
I was in a home earlier this summer where the homeowner had decided to put a sauna on the second story of his home. The home was new construction with the homeowner acting as the general contractor, and is located in zone 7, less than 100 miles from the Canadian border, and is in a rural location with no inspections. Construction is code minimum 2 x 6 framing with osb sheathing, R-21 fiberglass bat and class 1 poly vapor barrier, house wrap and smart siding. No rain screen. The vented attic was not insulated when I was there, but will most likely be R-49 blown fiberglass. The sauna is 6 x 6 with 8 foot sidewall, has one exterior wall and the vented attic above with the poly vapor barrier. There was also a small vinyl non-operating window. He intends to add foil faced bubble wrap to the walls and ceiling and finish with cedar boards(lots of little holes punched in the vapor barrier). The sauna stove is electric. I did talk the homeowner into removing the recessed can from the ceiling and he added a wall light on an interior wall. I have no idea how often the sauna will be used. Given the 100% humidity level and a possibility of 150 degree temperature difference between outside and inside temperature while in use, what kind of problems would be expected and what should he have done differently?