What material should I use to hide a duct running just above the floor in a closet?
I have used 1x2’s as the frame around ducts and plywood to make a shoe rack.
I usually use Sheetrock/ drywall to close in ceiling mounted ducts. No one knew or will know it is a duct if you disguise it and make it wide enough it become a feature.
I am sure you could use Sheetrock. make sure to have a shelf over it and there is less chance someone would step on it