i'm working on a bathroom in the basement that is already pretty low (6'7ish). due to limited space, i'm forced to place a toilet under a HVAC duct that has a clearance about 6ft. ideally i want to wall the duct work off but i don't think i can frame it off as it's be another 2-3 inches (min) forcing people to hunch over just to use the toilet. I'm 5'10
so i'm thinking my options are:
1. dry wall right on the duct with duct self drilling screws
2. leave the duct exposed
i fear that the 2nd is my best option but i'm not sure about rusting in for aluminum in a relatively wet area.