I'm rerouting some ductwork because of an expanded family room. Basically
the only way down to the first floor is thru a new closet on the second
floor. I plan on putting 2 8" registers in the first floor family room but
running ductwork between the ceiling joists will be tough.
I have heard that it is acceptable to simply use the existing ceiling joists
(boxed in on either side) as makeshift ducting. If I were to run 2 8" flex
ducts into the cavity between the joists and put the 2 registers somewhere
in the cavity - any problems with this? I was thinking I might need to put a
vapor barrier at least and maybe foil lined insulation (1/4") on the inside
of the cavity - what to you guys think?