Gas and Oil Home Heating Furnaces - metal heating ducts under concrete slab?

I have a 4-plex. The lower two apartments are half under ground with the heating ducts under a concrete slab. They are disintegrating so to some degree I appear to have tunnels in the earth going to the vents. What can I do about this?

Are you sure? Underground metal duct is usually PVC coated.

You may have legal recourse. The limitations clock may start with the discovery of the problem and not the creation of the problem. Negligence, workmanship and code requirements for underground ductwork are issues to search out.

Originally posted by lynn comstock
Are you sure? Underground metal duct is usually PVC coated.

You may have legal recourse. The limitations clock may start with the discovery of the problem and not the creation of the problem. Negligence, workmanship and code requirements for underground ductwork are issues to search out.
Lets say way back when. I have ran in to this before.For a time some of the companys to cut cost used the same tube in the ground as you see them use today for the round post they pour the concrete in.They where just rolled up cardboard and with wax on the ends. Like Lynn said we use metal today and, if the job looks like the ground is very wet and no drain for it under the slab then we use the metal with the PVC coat. ED

The problem is to find a cost effective solution. Chances are that there is nowhere else to run the ductwork. The ducts could go in an attic or soffit...maybe. This might salvage the equipment that you now use. See what you can do. Replacing the underground ducts with underground ducts is not an economically viable option.

There are ductless mini-split air conditioners. (No ducts at all)
http://www.toolbase.org/tertiaryT.asp?CategoryID=963&DocumentID=2028

There is the high velocity and high-pressure option, which shrinks the ductwork to fit into historic buildings and other places where ordinary sized ductwork won't fit. http://www.oldhouseweb.com/stories/Detailed/10443.shtml

Room air conditioners are the cheapest way out.

None of these options is very thrilling to recommend, but they are options.

Built in 1965 so I don't know how I would go about finding who is responsible much less get any relief.

Maybe it's not as bad as I fear. Heat does come out of all the vents. Would I just call a regular heating contractor to determine?

There may be room to put ducts above; furnace is right between the living room and kitchen. There is a lower ceiling that extends down the hallway past master bedroom and bathroom and into smaller bedroom. I'm guessing that this may contain vents for upper level apartments -- or plumbing?

If the metal rots to expose the earth, it may cave in at some point. Also you have an indoor air quality problem with exposed earth in the airstream.

Originally posted by Utahwoody
Built in 1965 so I don't know how I would go about finding who is responsible much less get any relief.

Maybe it's not as bad as I fear. Heat does come out of all the vents. Would I just call a regular heating contractor to determine?

There may be room to put ducts above; furnace is right between the living room and kitchen. There is a lower ceiling that extends down the hallway past master bedroom and bathroom and into smaller bedroom. I'm guessing that this may contain vents for upper level apartments -- or plumbing? I think you have your answer right there. Ill bet that for the cost of some dry wall a good tin bender could rework your duct work for the up and down stairs and just seal off the holes in the slab.Any good HVAC should be able to do this for you. ED;)