I recently bought a 40 year old house that has heating ducts in the slab. It occasionally has water leak into the ducts after a lot of rain. It dries up within a couple of days and there is no evidence that there has ever been any mold problems.
I just finished rerouting the ducts into the attic (MAJOR job), and removed the slab ducts from the supply feed. Now I need to close off the slab ducts. I have seen other forum posts suggesting filling them with concrete. Filling the entire slab duct would be a lot of concrete and a real pain.
I am looking for other (simpler/cheaper) alternatives. One would be to seal off a couple of feet each side of each register with conrete. An even more attractive solution I think would be to use expandable foam (like "Great Stuff") to fill around each register.
Does the expandable foam solution have any problems?? Are there other alternatives??
Thanks, JJ