Due to the many facets of window design, assembly and installation, window defects are common and can result in water intrusion. Problems may be caused by improper flashing installation, paper application, and improper use of sealants. Also, it is possible that the window itself is defective. Damage can be severe if not remedied immediately. Damages range from staining and cracking of interior drywall surfaces (especially on top of window sills), to structural member damage and ultimately dry-rot and mold infestation, if not addressed.

Causes of Window Defects

  • Improper flashing details
  • Issues with sealants or lack thereof
  • Physical deficiencies in the window itself


  • Our property has custom windows. How can we know if there are any problems or warranty issues?

    Custom windows are a great option for a unique look and great curb appeal. However, they should be installed and flashed just like any other window. Custom windows sometimes come with the added challenge of requiring custom flashings. Be sure your window installer is manufacturer certified and has the ability to create custom flashings. You want to avoid seams in the flashings over the mullions. You also want to be sure that there is sealant with backer rod between the window and the building envelope material(s). This will allow the window and building envelope to swell and shrink at different rates as temperatures change.

  • How can I tell if my building has window leaks?

    Sometimes window leaks are not immediately apparent. Other times, there can be a lot of water entering the building and no obvious source. Since windows are generally the largest and most frequent penetrations into a building, they are an important place to look. Look for dampness around and under the window sills. Check on the exterior of the building to see if flashings and sealants are in place and in good condition. If flashings or sealants are missing or in poor condition, there’s a good chance they are allowing water into the building.