I've been fixing up the ceiling in my garage, which is under living space. The ceiling joists need to be covered with 5/8" drywall since the furnace is in the garage.
But there are plumbing lines going in and out of the space between the ceiling joists, and running parallel to the ceiling joists, where the drywall would go.
So the best I can do is to fill up the space between the pipes with pieces of drywall. It's quite a mess.
I suppose to satisfy the building code, I should seal up the gaps between the drywall and the pipes with something. What? Some kind of fire-retardant foam? "Great stuff"?