On Apr 8, 9:38 am, "dpb" wrote:


So you're saying the cold air return "duct" in a two-story dwelling
was the wall cavity between two joists in between an external return
register/angle and short duct on each end?

If so, this violates every building code for fire blocking I ever saw
and should be corrected. You really should route a cold air return
somehow to connect the two ends w/ regular HVAC ductwork and ensure
there is blocking in the previous hole. Also, if there is a second
return also in the same fashion, it ought to be corrected as well.

This is common practice where I live (in residential construction) and
is passed by our building inspectors. Can't have an outlet in that
space, and wires and pipes must cross horizontally in a vertical
space. As for how you restore the return path, that is really going
to take someone standing there and figuring it out. There's no magic
answer. Don't think it really matters if it is in a duct or a joist
space. I think some remodelling is in your future!