Roof or Windows? 10 Tips for Finding a Sneaky Water Leak Around the House
Water leaking near your windowsill doesn’t always mean it’s coming from the windows—it could also be your roof
Picture this—you're enjoying the relaxing pitter-patter of rain outside your window when you spot some water near your windowsill. You may assume a leaky window is the culprit, but your roof may be to blame. Follow these tips to get to the bottom of the source of your leak.
1. Look for Water Stains on the Ceiling
If you’re on the hunt for a mysterious leak, the easiest way to start is by checking your ceiling. Look for telltale water spots or flow marks down the walls. If you spot anything out of the ordinary, chances are you’re looking at a roof leak.
2. Check Out Your Roof’s Step Flashing
Your roof's step flashing is the long, rectangular strips of flat material that run along the area where the roof meets the walls. It prevents water from entering the openings and cracks of a roof. If your flashing is loose, rusted, or damaged, this is the perfect spot for stray water to seep into your home.
3. Look for Rust on the Chimney Flashing
If your home has a chimney, it has chimney flashing, too. This could be a source of leaks because chimney flashing made of galvanized steel can rust and leave your roof vulnerable to pesky leaks. Pay special attention to the bend where the chimney meets the roof, as this is usually the first spot to succumb to rust and cause leaks.
4. Do a Complete Roof Run-Through
If your roof and chimney flashings are holding up well, you should troubleshoot your roof. Leaks from your roof could come from a weak spot—such as a damaged pipe, shingle, duct, or exhaust vent. These are all areas to check if you see actively leaking water during or within a day or so of rain (or when there is snow melting on the roof).
5. Look for Ice Damming on the Roof
While you’re doing your roof inspection, stay on the lookout for ice damming during the colder months. Melting water can run down to the roof’s edge, freezing into an ice dam and forming icicles. This can back up the water runoff until it finds a different way in—such as under the roofing or through the fasteners. If you have metal roofing on your home, this could also come through a seam or joint.
6. Check Your Attic Space for Condensation
It doesn’t just happen to your iced tea. Condensation from your attic or rafter space can run down the walls or elsewhere in your home, causing leaks that are quite far from the actual source. This is more likely during colder weather, and especially likely if you have metal roofing (which is prone to condensation or frosting).
If you have a walk-up attic (lucky you!), check for these signs:
Wetness on the underside of the roof
Wet or heavily frosted rafters
Wetness on the attic floor
If you don’t have an accessible attic, you may need to remove your bathroom fan or a similar fixture in order to get a view from below. If you have eave vents, you should be able to get a good look.
7. Look for Heavy Frosting in the Attic
We don’t mean the delicious kind. If you notice any heavy frosting in your attic space, this could be due to leaking exhaust fan ductwork. It could also mean that your exhaust fan is improperly ducted into the attic. As the weather warms up outside, this accumulated frost starts to melt in the attic—and eventually onto your prized hardwood flooring.
8. Inspect Your Window Flashing
Thought we were done with flashing, huh? For suspected window leaks, check your window flashing. This is the thin, continuous strip of material around the window that keeps water from coming in through the gaps. Look for anything that’s damaged, missing, or otherwise failing.
If the leak seems to be coming from above, pay special attention to the drip edge, which is the L-shaped piece of flashing at the top of the window.
9. Check Around the Window Frame
Windows that leak during rainfall will often cause damage or decay to the window frame. This can lead to water leaking from underneath the window sill or in the surrounding area. Here are some common areas to check:
Checking the sealed area between the window frame and the glass. If you see the caulking is old or worn down, it may be worth re-sealing the glass.
Examine the window sill on the exterior of the house. It should have a slight tilt that faces downward to ensure water flows off and away from the window.
Clean around your window frame to clear out dirt and debris that’s built up over time, including around weep holes and the window sash.
If your window frame is made out of wood, gently press into the frame with your fingers or a screwdriver to check for wood rot.
10. Know Who to Call for Roof and Window Leaks
Once you’ve determined the source of your leak...now what? Scrappy DIY-ers might find their answer on Google, but that’s not always the best option (especially if you still have a warranty to fall back on).
If your new roof is leaking, it’s likely still under warranty. Contact the roofing company directly and they should be able to handle the necessary repairs. For an older roof, your best bet is to contact a roof specialist near you. It could be a simple fix—some roof repairs cost as low as $400.
As for who to call for window leaks, you can contact the original window company if they’re still under warranty. If not, a local window repair specialist should be able to take care of your leaky problem. Most window repairs cost around $400, but a full window replacement costs around the same amount. Depending on the age of your window, it may be more cost effective to replace it.