I was looking at the duct work to and from the furnace and noticed that the return air ducting is needing repair I think. What is going on is the return duct is using the space between two floor joist. The sheet metal has come out of its track? the sheet metal is up into the joist space. I assume this should be pulled back down and re secured into its track, but the regular ductwork is hanging underneath about three inches. What do I need to do here?
Well, you can see how its supposed to be, just make it like that. There is a hole in the top of the duct that pulls air from the joist bay(s) and sheet metal panning sealing the joist bays essentially making them ducts. Just use common sense and put it back up the way they should be. You can use sheet metal screws to fasten the panning and duct mastic to seal it.