No announcement yet.

Question about duct work

  • Filter
  • Time
  • Show
Clear All
new posts

  • Question about duct work

    My wife and I just purchased a house in MA and a dual zone central air system has been added. All of the duct work in the attic has been insulated and most of it in the basement is also insulated, but not all of it. On the duct work that is not insulated you can see where condensation has built up on the outside and then dried in the past. It also looks like there might be some mold. Is this something that I can change out myself or will I need to call someone in to look at it?


  • #2
    Mold on duct work,,,,,

    Wash down duct with hot water with a mixture of bleach to kill mold,, Then insulate ......Tom..


    • #3
      I belive Tom has the right idea for cleaning the ductwork. Also if there is a built in humidifier. The setting may be to high wich would make the air nice and moist perfect for growing mold. As for insulating it. Personally i would just use mastic on the seams. Ive never seen a real need for the insulation.


      • #4
        I dont think the mold would grow on bare sheet metal alone. if it is like a white powder i think it would be the zinc coating reacting with the moisture.
        if you have a/c you should insulate all areas of the duct you can get to, this will stop condensation on bare sections on very humid days.
        You can probably fix all this stuff your self if you are handy with tools.
        I also live in mass. and can direct you to a supply house that you can find the needed supplies.
        I own a small sheet metal company and could probably tell what you need if you posted a few pics of the problem.



        • #5

          You are correct. It is more of a white powder on the outside that has formed. I would love the name of the supply company that you speak of.




          • #6
            It does not seem like you need to replace anything. If all you duct is intact, I would just seal the seams and joints with a duct sealer [about $20 per gallon and you brush it on with a disposable brush]
            and than insulate the bare ducts to stop the condensating. if the duct that is insulated already looks like tinfoil you should use "FSK" duct wrap1.5" thick.
            If it is gray you should use "vinyl" duct wrap 1.5" thick.
            400 square feet [4'x100' roll] should be around $150.
            either way you just wrap around the duct the best you can and staple the corner with a staple gun like an Arrow P35 staple gun [about $25.]
            all is available at any HVAC supply house

            in waltham there is Delta t at 77 felton st. 781 893 0800
            in Burlington Air purchase at 24 Blanchard RD. 781 273 2050

            feel free to ask any more question

            Good luck