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  • Ice crystals on sheathing

    I removed some drywall from an exterior wall and found ice crystals on the back of the sheathing. It's not ice like the roof was leaking just ice crystals.The wall was insulated and had a sheet of plastic as a vapor barrier. It only occurred on the bottom couple feet of the corner as far as I can tell. Anyone have any idea how to fix this"

    Thanks,
    Doug

  • #2
    Re: Ice crystals on sheathing

    It's really hard to tell, Doug, but here's a couple scenarios to check out. By the way, I'm assuming the ice was on the exterior side of the wall, on the cold side from the vapor barrier. If it's on the warm side of that barrier, there's probably a hole in it somewhere.

    First of all, you have a roof holding TONS of snow weight. The bottom of this snow (in contact with the roof) can start to melt, and it will find a way in. Even if your attic is properly insulated, it's just the amount of snow over top along with sunshine that causes the melt. That meltwater from the roof goes down the inside of the exterior layer of wall and finally finds a cold spot and freezes. You should be able to see where the water is coming in at the eaves and dripping on the inside of the wall.

    You may just have a hole in the exterior sheathing that's allowing water in, which then freezes. Look around the highest point you see water and trace it up to see if you can find a hole somewhere.

    Check the moisture barrier to make sure it's not leaking somewhere, allowing moist warm air out to condense on the inside of the exterior sheathing. It doesn't take much air to start to condense water when it hits a cold surface. Make sure your insulation is dry. If it's wet, you'll have to pull it and replace it.
    I put it all back together better than before. There\'s lots of leftover parts.

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    • #3
      Re: Ice crystals on sheathing

      Originally posted by dugan View Post
      I removed some drywall from an exterior wall and found ice crystals on the back of the sheathing. It's not ice like the roof was leaking just ice crystals.The wall was insulated and had a sheet of plastic as a vapor barrier. It only occurred on the bottom couple feet of the corner as far as I can tell. Anyone have any idea how to fix this"

      Thanks,
      Doug
      sounds to me like heat loss.make sure you have the walls insulated properly.also make sure that the insulation is tight against the top and bottom plates to assure you dont have any heat loss in those areas.i had the same problkem on one of my jobs and a helper we had at the time installed the insulation improperly.any questions let me know

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      • #4
        Re: Ice crystals on sheathing

        You could always install a roof deicing system. Products from Heatizon Systems allow you to cover up all the cables and copper mesh used to melt the snow with shingles. I highly recommend them to anybody looking for any sort of roof deicing system.

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        • #5
          Re: Ice crystals on sheathing

          Originally posted by sirrinem View Post
          You could always install a roof deicing system. Products from Heatizon Systems allow you to cover up all the cables and copper mesh used to melt the snow with shingles. I highly recommend them to anybody looking for any sort of roof deicing system.
          3 posts and they all mention the same business

          Coincidence or SPAM?

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          • #6
            Re: Ice crystals on sheathing

            There will always be condensation in walls, that's typical. This really doesn't sound like a moisture leak, more like the heat loss leak. builda hit it right on the nose, reinsulate, but make sure you do not have an air gape from exterior sheathing and bottom plate. This Ice Crystal problem is very typical in MN, when the insulation isn't done properly. Even the paint will bubble after freshly applied, if cold air hits the drywall. I have seen it, many, many times with new construction even.

            Check for mold and fix it, before you close up that wall.
            Last edited by garager; 06-24-2009, 12:25 AM.
            Great Link for a Construction Owner/Tradesmen, and just say Garager sent you....

            http://www.contractorspub.com

            A good climbing rope will last you 3 to 5 years, a bad climbing rope will last you a life time !!!

            Comment


            • #7
              Re: Ice crystals on sheathing

              Definetley sounds like air infiltration. Moisture could be coming from inside the home, possibly up from the basement through a chase, and freezing on the exterior sheathing. If you're going to reinsulate maybe consider dense pack cellulose instead of fiberglass( i'm assuming that is whats existing).

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