Locating window leaks in your home can be challenging to say the least, as the source of the leak could be something other than the window itself. In fact, water intrusion near the top of the window, more often than not, comes from another source, such as a roof leak, clogged gutters, failing flashing, or damaged soffits.
In the photo above the window itself appears to be just fine, and it is. However just weeks after this storm damage, water stains began to appear on the drywall on the interior of the home just above the window frame. The homeowners first instinct was “I have a window leak,” yet in fact the culprit was damage to the roof. This allowed water to migrate down the wall framing where it settled along the top of the window. Now you can see why locating window leaks can be so tricky.
Locating Window Leaks After a Storm
Okay, I’ll admit that locating window leaks after a tree falls on the roof of your home, as in the photo above, may be just a little too obvious. Damage from falling trees can include shingle damage, holes in the roof deck itself, gutter damage, or structural damage to the soffit and facia boards. But you also need to inspect the following areas on the windows themselves:
- Window Sill: The window sill should be angled down, sloping away from the wall. It’s rare, but I have come across some poor installations where the window sill was flat and level. This will definitely lead to a window leak at some point and requires major rework. Time to contact the Window Repair Guy!
- Lower Sash Seal The lower sash should sit tight against the window sill to stop driving rain from entering. Raise the sash to inspect the seal that runs along the bottom of the lower sash and replace it if it is rotted or damaged.
- Caulking Issues: It’s time to break out the ladder so you can look at the top of the window frame and inspect the trim caulking. Check for gaps between the drip cap and the siding. Inspect the caulking between the underside of the drip cap and the window casing. If you find any openings or if you see caulking that is deteriorated, re-caulk the area. Do the same for the vertical sides of the window casing as well as the underside of the window sill.
- Meeting Rail Seal: Many double-hung windows have a seal where the meeting rails of the upper and lower sash make contact with each other. While this isn’t usually a source for water intrusion, it can happen in a driving rain. Inspect and replace the seals if needed.