©2013 Green Building Advisor. From The Taunton Press, Inc., publisher of Fine Homebuilding Magazine.
I'm doing an interior finish for a hot yoga studio in Edwards, Colorado, 7200 ft in elevation. The1000 sf studio will be heated to 105 degrees and 60% humidity 3 times a day. lasses are at 9:30 am and between 4:00-7:30 pm. The studio will be on the second floor of an older wood framed building. There are tenants on either side and a vaulted ceiling/roof above. The north and south walls are 24' wide with 2x4 framing with plywd. sheathing (building paper?) and t-111 siding with a couple of windows and a door on each side. The shared east and west walls are 40' with drywall and insulation. The roof is insulated with batt insulation, R30-38? I don't know the roof assembly yet other than 3:12 slope, built up roof, minimal venting. We are not putting any lights in the ceiling. The heat will be provided by a 100,000 btu gas forced air unit. (It has to be big for the sf to ramp up the heat quickly). After each class the room can be vented to drop the heat and reduce humidity.
The owner's previous studio, in a nearby location, did not have moisture or condensation problems except on cold days at a bad window and a glass door on an eastern exterior wall. There were no moisture/mold issues in the walls or ceiling after 10 years. The studio had a dropped ceiling. The dry climate is a big help.
The new studio finish has a very limited budget.
My question is about the wall and ceiling assemblies. I am concerned about condensation forming on the ceiling and/or walls on cold days/nights. I also don't want to create problems in the ceiling or walls. At the extreme, temps here can get as low as -20 at night in the winter. I'm trying to sort out how best to detail the space. Is the r-30 rafter insulation adequate for the temps and moisture in the studio if it is well-sealed? What about the walls at r-13? (Neither walls nor ceiling meet the current code). Should I be more concerned about condensation, vapor penetration, or insulation? Do I need to add a layer of foam board and drywall at the interior to seal and insulate the space? What are the biggest concerns here? Any thoughts or comments would be a great help. Thanks, Rick