Why Are My New Windows Leaking?

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Mar 16, 2015

Feb 20, 2024

4 min read


You may have had a new window replacement project done recently, or even in the last few years, only to notice leaks forming on and around your frames as the winter snow begins to thaw.

Knowing the cause of the leak is crucial in determining how the issue is going to be fixed, and ultimately who should be responsible.

Generally leaks are a result of one of two problems: improper window installation, or product defect. In some cases, the installation may have been performed correctly, but the process disturbed components in the structure or exposed blockages from other structural leaks. Your old windows may have kept the water in the wall structure, but as debris got removed during the full frame replacement, the water now has a clear passage and shows up as ugly stains around your window.

Installation is a HUGE determining factor in the final cost of your vinyl windows. No matter how good or energy efficient the product is, if it isn’t installed correctly, it nullifies your investment and ultimately can cause more problems than good for your house.

A common installation issue that results in leaks are windows that are not plumb or level. If a window is tilted to one side or the other, it will ultimately collect water and cause it to pool. This may not be as big of an issue with awning or casement windows, but should be especially looked after in windows with drainage channels like the slider. By simply placing a level on your windows, you can see whether they were installed properly or not.

Another common reason for leaks related to the installation is the improper sealing of the windows. Most installers today use expanding foam to seal and secure the window frame to the rough opening. Too little foam may leave air channels between the window and the wall for water to come down through. This is also where correct window measurement is crucial. If your custom windows are too small for the opening, it is simply improper to fill the large gap with foam.

Caulking on the outside of the window acts as an initial barrier to prevent the water from going in, and should always be done correctly and fully. But even with incomplete caulking, the expanding foam should still not let moisture through to the inside of the house.

With either of these installation issues, the window companies in charge of your replacement are also responsible for the proper installation. If you suspect your windows are leaking because they’re not level or because of inadequate foaming or caulking job, contact the company immediately.

Product defects are less common causes for leaks in the window. Although not always, but they can be identified by the colour of the water that is pooling on your sill. If the water is clear, chances are it came somewhere through the window, and not frame or wall components. These leaks are often a result of a defect in the manufacturing process or damage during shipping or installation. Bad seals, cracks, or simple manufacturing errors can lead to new windows leaking once they have been installed.

Usually in these cases, the manufacturer is responsible for replacing the windows, but you would still have to contact your company as they are they ones who provided the service, and ultimately carry your warranty.

Leaks that come from within the wall structure, but have been exposed by the installation are trickier. In most cases, the installers will not be responsible for addressing these issues, so you’re on the hook for bringing out an inspector or a general contractor to take a look at what could be done. Though installers may be able to recognize these leaks during the replacement process, they are often difficult to see until the windows have actually been installed.

Check out our previous post on how to recognize some of the leaks. If you see these patterns on your existing old windows it may be a good idea to have someone examine them before the day of your installation, and properly address the problem.

Determining the cause of the leak, is a major step in fixing it properly.

Check out these window replacement articles:
Learn how much a window replacement should cost
See our full line of vinyl window styles
Find out about all the installation services our company offers

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