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Community and Q&A

Water infiltration/condensation problems

levassep | Posted in GBA Pro Help on


The climate zone where my bulding is, is 7or 7A, It is located in the southern part of province of Quebec, Canada, village name is Saint-Philemon.

The buiding is 2 stories, 28×24 floor surface, south wall on each story has 2 windows 9’x7′.

Wall layers from exterior are : wood clading, wood lathe(1×3), air barrier, styrofoam (2”), sheating OSB 58, 2×6 spruce wall filed with mineral wool, plastic vapor barrier, wood lathe(1×3), sheatrock/gypsum.

There is water comming out at the bottom of the south wall between the sheating (OSB) and the styrofoam (Isoclad 2”). There is also some water coming in the buiding at the edge of the 4 south windows.

I have also observed water inside the frame of the window in the middle horizontal part that contains wood. See images.

I’m trying to figure out where the problem is coming from and if it is a condensation problem or a water infiltration problem.

What steps do you recommend to follow to find the problem and solve the issue.

thank you for your help,


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  1. levassep | | #1

    I forgot to tell that the water dripping at the bottom of the wall isdripping just under of 2 lower corners of each widows so I have 4 dripping site.

  2. user-2310254 | | #2


    Do you know if the window openings were properly flashed? From your description and photos, I assume this is a fairly new house.

  3. levassep | | #3

    There is no membrane in the rough opening, nor there is membrane linking the window with the air barrier. The space between the widow and the rough opening has been filled with spray foam. There is a metal drip edge on top of the window and the vertical edge of the window is sealed with silicone to the wood cladding.

    The house is 2 years old.

    What is really strange is that there is water inside the frame of the window on the inside side. I will add more images soon.


  4. DanCK | | #4

    Hi Pierre. You should test the window unit itself to see if a seal has failed. Try a water hose or create a little water dam along the bottom of the window with tape and fill it up. Easy way to start investigating

  5. GBA Editor
    Martin Holladay | | #5

    If the moisture is showing up at the lower corners of the windows, this is almost certainly rain, not condensation. As Daniel suggested, you can do some testing with a garden hose and a spray nozzle to figure out whether this is wind-driven rain.

    From your description, it sounds like your builder forgot to flash the rough opening before installing the window. It's also unclear from your description whether your wall has a water-resistive barrier (WRB) -- in newer homes, this is usually a plastic housewrap like Tyvek or Typar. (Probably, that's what you meant when you wrote "air barrier" in your wall description.)

    If my guess is correct, and your window rough openings have no flashing, you have a big problem. All of your windows need to be removed so that flashing can be installed. For more information on flashing rough openings, see this video series: Flash Rough Openings for Windows and Doors (8-part series).

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