A poorly installed window can lead to premature window failure, sticky operation, a voided manufacture’s warrantee, and leaks which can lead to building decay and structural failure. With over two decades of experience making construction defect repairs on condominiums, I have seen a lot of poorly installed windows. These installations are often performed by contractors that provide a low price because they take short cuts. Often these businesses have no “completed operations insurance” for their finished installation and they soon go out of business leaving no recourse for the property manager or it’s client.
Your new window needs a nail flange.
The most common way a window installer will cut a corner, is to remove the window nail flange. This allows for installation without removing any cladding or building weatherization, which is against the manufacture’s recommended installation methods. A contractor using this method of installation does not remove the building siding or trim, but rather, they cut the old window out with a saw while leaving a portion of the old window buried behind the old cladding. The new window is held in place by placing screws through the side of the window, compromising its design. An exterior caulking joint is often installed around all four sides of the window using this technique. This is the only prevention for keeping the moisture out of the opening. By sealing all four sides of the window it prevents moisture from properly drain out from under the cladding around the window. Windows installed in this method are often called “remodel or replacement windows”. These are terms to look for, and avoid, when receiving bids to replace your properties windows.
Proper Window Installation
The new window must be installed per the window manufacture’s installation instructions, to the letter. If you can’t find the instructions or if your situation is unusual, ASTM E E2112-07 “Standard Practice for Installation of Exterior Windows, Doors and Skylights” is a great reference. This requires the window to be weather lapped into the buildings weather resistant barrier (WRB) under the siding. This will maintain the buildings existing drainage plane so that any water leaks are directed outside the building. To accomplish this, the existing siding and/or trim needs to be removed to obtain access to the WRB. Installing a window pan made of self-adhered membrane, sheetmetal or PVC is a great idea also. The pan is a three dimensional shield that catches any water that may get through the window system and diverts it to the outside. Metal head flashing should be installed above the window as well. A gap above the metal flashing is purposely left un-caulked to allow moisture from behind the cladding to drain out. Siding and/or trim should be held back ¼” – ½” off the other three window sides for a properly engineered caulking joint installation.
Windows require inspection and regular maintenance. Windows have a certain life expectancy depending on their composition (Wood, Vinyl, Metal, Fiberglass, ect.). Over time these products do wear out and may leak. This is why installing a window pan under the window is a good idea. Areas of failure may be failed perimeter caulking, broken window frames, and failed seals and gaskets. Broken or sweating glass panes can be replaced without removing or changing the window frames.
Windows are all designed to take on water, collect it and then expel it to the exterior of the building through weep holes. You should find these weep holes along the bottom outside of the window frame. When under extreme weather conditions you may see standing water on the inside of your window track. This water is moisture the window has taken on, where the weeps can’t keep up, however, as long as the window expels the water before it overflows the inside track, it is operating as designed. For this reason the window tracks and channels, including weep holes, must be cleaned along with the glass on a regular basis. A good window cleaner will inspect these items and remove the window components to perform a proper cleaning. This will help keep your window operating smoothly and maintain its ability to drain as designed.
New windows can update a community’s appearance while providing great energy savings. Insuring you receive a good installation and proper maintenance on your windows is important to maintaining the life and value of your communities building.