Return duct in basement
I'm finishing my basement and there's only really one decent (central) spot where a return duct could be installed. It's a relatively small section of the wall, so there are two 2x4's and 13" space in between. Is this sufficient for a 900 sqft basement?
The other question I have is that I also want to use that small wall section to hang up something, so I was going to route a 1/2"x1/2" strip off the two 2x4's and install a 1/2" plywood flush on that wall section, so that there's something more sturdy underneath the drywall. That would reduce the duct by 1/2". Is that still ok?
I assume a contractor would use sheet metal on all 4 sides of the duct? Or do they just use sheet metal where the duct would meet drywall?