By RatLabGuy
I’m working on finishing 2 ajoining rooms in my basement.
House is a classic late 70s ranch, with the typical setup of a main supply and return trunk running the midline and 6″ branches running off to the rooms above.
When the PO built the house, they went ahead and ran a number of supply branches with registers facing down to air the basement as well.
There is of course no real return since it’s just a big open space.
So when I frame in these rooms, I need to add a return.
All of the existing return “ducts” are just flashed-in joists and between-stud space. Ugh.
To do this, I was going to take advantage of an existing line (made of flashing… see pic) and frame a column that will go down to the floor, and put a register on either side of the column (one serving each room).
(Yes, I know I am “stealing” from the vent above it… however as it turns out this vent is the 2nd in a large room, and the PO already framed in a desk over it so the register ended up inside a cabinet… it’s essentially doing nothing now so I was going to block it off anyway.)
The easy way to do this would be to just cut out that flashing, use the column as a giant “duct” and add the two registers. However (a) I know that’s not the right way, should use real duct, and (b) there is a gas line going up to a fireplace insert that is in the column space. The space beside that the gas line goes through is inside a soffit so it will be hidden.
What’s the best way to deal with this? Should I fab up a flex duct that ties into the flashing, around the gas line then goes down to a tee for each register?
it’s got to be fairly big for the combined space, rooms are ~145 & 300 sq ft.
However… I also anticipate little need for high heat/AC flow down there, aside from general air flow, the climate stays great and very dry even w/ everything blocked off.
Source: DoItYourself.com
