There's water getting in around my window frame when it rains - what's going on?

Water infiltration around window frames is typically caused by failed weatherstripping, damaged caulking, or improper installation - and it needs immediate attention to prevent structural damage and mold growth.

The most common culprit is deteriorated exterior caulking around the window frame where it meets your home's siding. Over time, this caulk shrinks, cracks, or pulls away, creating gaps that allow water to penetrate. You might also have worn weatherstripping around the window sash that's no longer creating a proper seal when the window is closed.

More serious causes include improper flashing installation during the original window installation, or the window itself settling and creating gaps in the frame. In Ottawa's freeze-thaw climate, these small gaps can expand significantly during winter, making the problem worse each year. Sometimes the issue isn't the window at all - it could be water running down from a roof leak or damaged siding above the window.

Start with a visual inspection on a dry day. Look for obvious gaps, cracked caulk, or damaged weatherstripping around the entire window perimeter. Check both inside and outside. During the next rainfall, try to pinpoint exactly where the water is entering - this will help determine if it's a simple caulking job or something more complex.

For minor caulking issues, you can apply exterior-grade polyurethane or silicone caulk as a temporary fix, but if water is getting into the wall cavity or if you see multiple entry points, this likely requires professional attention. A licensed installer can properly assess whether the window needs adjustment, new flashing, or complete replacement.

For a thorough assessment of your window's condition and proper repair recommendations, consider getting a free consultation from Ottawa Window Pros - water damage only gets worse with time.