Garage interior wall cladding with exterior rigid insulation
Hey everyone, first time post here. First off, I wanted to thank everyone for all the great information, I’ve used this site a ton! However, I haven’t come across information regarding the specific wall assembly I’m interested in. I am building a house in NW Minnesota (climate zone 7). My wall assemblies are 2×6 stud walls filled with unfaced fiberglass batt insulation, 7/16 OSB exterior sheathing, 2 layers of 2” XPS foam, WRB, plywood furring strips, vertical corrugated steel siding panels. I’m unsure of what to put on my interior garage walls. It’s common in this area to put white corrugated vertical steel panels on garage interiors, which I would like to do (easy to clean, very bright, durable, easy install) but I’m concerned about moisture control in my wall assembly. I would think the steel interior cladding would reduce my interior drying capacity to near zero, or would the corrugations and small gaps at the top and bottom of the wall panels allow for adequate air flow and drying capacity? Or would drywall and latex paint be a safer route? Any advice would be much appreciated.
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Replies
Is your garage going to be an attached garage, and is it going to be conditioned? Where is your air control layer, the exterior OSB? If the house is completely air sealed from the garage (which it should be no matter what due to fumes and chemicals,) and the garage is not conditioned, then I wouldn’t bother putting exterior insulation on the garage and you don’t have to worry about drying of the garage walls because there will not be a vapor drive if the garage is unconditoned. Im curious what these white corrugated panels look like installed, and what is the advantage over drywall. It sounds more expensive than drywall so there must be some advantage.
I’m not use to seeing the WRB on the outside of the foam rather than the outside of the OSB. Are you taping the foam to be your WRB?
Similar to the white corrugated panels your are looking at, I have considered “slat wall” panels which are plastic and are also zero perms. My solution is going to be to install perforated soffit-like material at the bottom and top of the walls to allow drying even though the majority of the wall is zero perms. I’m not sure how easy it would be to get a good-looking match in your case since the panels are metal. I think they make perforated metal stock but I haven’t worked with it.
mattew25,
One of the advantages of moving the WRB outside the foam is being able to keep all your flashing at that plane, rather than running them all back to the sheathing
Adrienne - The garage is attached to the house, they share 36’ of wall. Garage space is heated to ~50 deg F in the winter, not conditioned in summer (besides portable dehumidifier use as needed). Garage space is totally air sealed from house space. Exterior insulation is already applied to the garage. If you search “garage interior steel” you’ll see many images of garages/shops with this interior cladding.
Matthew - I went back and forth with which plane to place my WRB and eventually settled on exterior to the rigid insulation. Like Malcolm said, it places all of your flashing in the same plane. Seems a lot cleaner around windows to me, but this is my first go with the rigid insulation.
I have considered some type of perforated material at the top and bottom of the wall assembly to promote air flow. Like you said, getting a good match might be tough. I’m
also a little leery of perforations near the floor, I do quite a bit of metal work (cutting, welding, grinding) and have visions of sparks getting into the wall assembly.