A Troubleshooting Guide To Window Moisture Problems

You depend on your home's windows to provide natural light and open views without allowing the elements to find their way inside. A leaking window isn't just a nuisance, but it can lead to structural issues likes rot, water damage, and mold. Discovering the cause of the leak is the first step towards solving the problem.

Damaged Flashing

The windows on your home have flashing installed around the seam between the window frame and the wall. The purpose of the flashing is to keep moisture from working its way into the seam. Over time, flashing can warp, become damaged, or simply wear out. When this occurs, moisture may begin to seep through the seam and into your home. If the damage isn't noticed and repaired promptly, rot may set in if you have wood window frames. Once the frames begin to rot, the best repair option is to replace the entire affected window. Regularly inspecting the flashing can help you catch any issues before rot occurs.


Condensation on the inside of the windows is typically caused by too much humidity inside the home, as opposed to a problem with the window itself. Although water isn't leaking in, it still causes damage similar to a leak. Unfortunately, if you don't address the condensation problem, rot can affect the interior sill and frame. Installing a dehumidifier can help solve the problem so that you won't have to worry about permanent damage to the window frames.

Failed Seals

Sometimes condensation occurs between the panes of glass in double- and triple-pane windows. The cause is typically a broken seal that has allowed the insulating gas between the panes to escape and allowed moisture to make its way in. One repair option is to have the window pane vented so that moisture can escape. Although this will stop condensation issues, it can compromise some of the insulating qualities of the windows. If window insulation is important to you, then replacement windows are the best fix.

Broken Glass Seal

All windows are sealed in place, typically with some sort of caulk. There is also weather stripping around the window that seals out moisture. If the caulk or weather stripping begins to fail, then moisture can easily leak into your home. It's usually possible to remove the old seals and caulk and replace them with new as long as the rest of the window and frame are in good condition.

Contact a window replacement service if the leaks aren't easily repairable. Sometimes the best fix is having new, updated windows installed on the home.