Question

Why are we getting condensation in the corners of our wood windows and ice buildup around the crank-out openings?

Asked by Bryan Beauduy
Duluth, MN

New Pella replacement windows installed. No condensation on windows themselves but more condensation (ice and frost buildup) in corners of frame where trim encompassing fixed-pane window meets frame on inside. Also, we are getting ice buildup around the frames of the crank-out portion of the windows. Pella says it is from too-high humidity (we have 32-38% humidity in the house). More noticeable when temps got to -10 to -30 F. I can also feel draft from the corners.

Answer

Bryan,

This is due to the lack of properly installed insulation between the window frame and rough wall framing or old window frame.

As you had mentioned, these are replacement windows. In most cases they are installed from the interior of the home and finished off on the exterior with aluminum trim.

  • If no insulation was installed around the window frame during the installation, you now have a direct path of heat loss to the outside and air infiltration into the home, creating condensation and drafts.
  • This continuous buildup of moisture will become a source for mold and mildew growth and in many cases an invitation for insects such as carpenter ants.

I would contact the company whom you hired to installed the windows to remove a section of trim in an area where you are experiencing the problem.

If there is no insulation present or improperly installed, it should be their responsibility to:

  • inspect all windows they installed, and
  • repair the defect and any associated material and labor costs free of charge to you.

 

For more information:

Read "Should we insist that our contractor use expanding foam insulation around our new windows?", a Q&A with Carl Seville.

Tagged In: energy efficient window

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