I am working on some home improvements and I just don't know enough about ductwork to fix this issue. All of the ductwork in the basement feeds up through the floor and uses the plenums to move air up to the second floor, even using exterior walls (filled with insulation).
The first floor vents just have the duct work shoved into an oversized hole. Lots of dust and cobwebs and such around the openings, and presumably the air isn't going where it is intended.
My two questions are: what is the proper way to "transition" from duct to plenum/through the floorboards. Should I use foil tape to seal all the gaps, and then maybe Great Stuff to insulate it a bit??? I can't seem to find any good information on how to properly do this.
Second question, is that normal, to use exterior wall plenums which have batts of fiberglass insulation in them to move the hot air? That seems odd to me (home was built in 1979)
Thanks in advance