Our basement family room has several vents, which were at one time connected to the furnace. The entry from the furnace duct has since been sealed, but the duct runs remained, and the vents were stuffed with fiberglass insulation and forgotten. Then we came along.
I opened one of the vents tonight expecting to spray in some foam and seal it off, thinking it was the end of the run, and was galvanized. Instead, I found 8" clay tile which ran in both directions from the vent, and appeared to extend beyond the back exterior wall. (see photos) I can't imagine why a heat run would lead outside! The plan now is to build a structure with treated lumber and exterior plywood to create a floor and cap this hole, then tile over the whole shebang with Ditra and ceramic. (I will create a channel to allow any water to escape below the treated wood).
I am curious, is this kind of "ductwork" typical of the late 1950s? Should I have any other concerns? I can't think that pumping in concrete is a good solution. Would filling each end with foam be a good plan? My cats have always been fascinated by this vent, so I assume we get some visitors there! Just looking for thoughts and ideas about how to deal with this, or just cap it and ignore it.