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  1. #1
    Join Date
    Dec 2011
    Posts
    3

    Default In-slab duct repair

    I have a single floor house build in the 50's. The house is on a slab and the duct work was build into the slab. I has noticed that when it rains alot we get water in our vents. This is causing multiple issues. When we run the heater or AC it gets real humid in the house and smells like meldew. I was wondering how I would go about repairing the old ducts with out busting up my foundation. I have a down force gas furnace so running new ducts in the attic is not an option either (as far a I know).
    Last edited by gdickson; 12-07-2011 at 08:21 PM.

  2. #2
    Join Date
    Jul 2009
    Location
    Northeast
    Posts
    661

    Default Re: In-slab duct repair

    I doubt that your going to be able to fix the present duct system without tearing up the floor, is it ground water that seeps in as the water table rises or is it coming in from the chimney through the furnace. If it's ground water I would remove the furnace, fill the hole in the floor with cement and replace your downflow with an upflow, rerun your ductwork into the attic with supplies to each room, rework your return out the closest wall by the furnace. If the water is coming in through the chimney fix the leak. If you have a high enough pitch on your roof you may be able to put a horizontal furnace in the attic and run your ductwork accordingly. Good Luck!

  3. #3
    Join Date
    Dec 2011
    Posts
    3

    Default Re: In-slab duct repair

    Thank you for your reply.
    The water is coming from the ground water. I ran my shop-vac in the ducts to try to clean out as much water as I could and sucked up alot of mud. I would love to just replace this furnace with an up-flow one but can't afford to make that purchase at this time. Too bad I just can convert the one I currently have. I do need to do something, the air quality in my house is aweful.

  4. #4
    Join Date
    Jul 2010
    Location
    SoCal
    Posts
    5,084

    Default Re: In-slab duct repair

    Some furnaces can be used with up flow or horizontal ducting, so it might be worth it for you to check if your specific unit could be converted. Contact a reliable HVAC guy.

  5. #5
    Join Date
    Dec 2011
    Posts
    3

    Default Re: In-slab duct repair

    Thank you for your reply,
    I will do that, I was not aware that some units could be converted, I was told it one way or the other.

  6. #6
    Join Date
    Jul 2009
    Location
    Northeast
    Posts
    661

    Default Re: In-slab duct repair

    I don't think they can be converted as that would also mean changing the burner assy, and heat exchanger but I may be wrong. As dj1 says check with a reputable HVAC Co. Good Luck

  7. #7
    Join Date
    Jun 2009
    Posts
    254

    Default Re: In-slab duct repair

    Check with company that do sewer pipe repair they insert a dry sleve looks like a sock inject hot water or steam this causes the duct to be lined with a plastic like material than a robit is placed in the dout to cut the openings where required.
    Final product is a one piece duct no joints.

  8. #8
    Join Date
    Dec 2010
    Posts
    24

    Default Re: In-slab duct repair

    Quote Originally Posted by Clarence View Post
    Check with company that do sewer pipe repair they insert a dry sleve looks like a sock inject hot water or steam this causes the duct to be lined with a plastic like material than a robit is placed in the dout to cut the openings where required.
    Final product is a one piece duct no joints.
    this would be the best way, but its very expensive

  9. #9
    Join Date
    Dec 2011
    Posts
    5

    Default Re: In-slab duct repair

    The previous owners of our home had thee same issue, and put a furnace in the attic and ran duct work from there. They never filled the ducts or put in cold air returns, so make sure you or a contractor to the complete job! It actually works quite well, and having the furnace in the attic freed up some main floor space in the house. Good luck!

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