4 Common Causes of a Leaky Roof in the Winter

Kristi Pahr
Written by Kristi Pahr
Updated October 29, 2021
Brothers playing with snow in the yard
Photo: Cavan Images / Cavan / Getty Images

Leaky winter roofs are “snow” problem—learn four common causes and get prevention tips

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Winter is a magical time full of snowmen, holiday lights, and hot cocoa—but it’s not always the greatest season for your roof. Learn all about why winter roof leaks happen (hint: your roof may not even be the problem) and get roof winterizing tips so you can enjoy the colder months without worry. 

What Causes Winter Roof Leaks?

It can certainly put a damper on your winter cheer if nasty weather is seeping down into your home. But if your roof only leaks during the winter, it may not actually be the culprit. 

Learn a few common reasons your roof may only leak during the winter months and the issues a leaky roof can cause.

Ice Dams

Ice dams and snow on roof and gutters
Photo: Maudib / iStock / Getty Images Plus / Getty Images

Ice dams form when snow collects on rooftops. As the snow melts and more snow falls on top, the water from the melt refreezes over the eave. 

As more melted snow moves to the eave, a dam forms and meltwater is pushed back under your shingles, eventually making its way into the attic, insulation, and eventually walls. Ice dams can result in leaks that cause structural damage and compromise the integrity of your home’s sheetrock or wallboard.

Attic Condensation

If your attic isn’t well insulated, warm, moist air from your home can enter. Because attic temperatures are cooler than living space temperatures during the winter season, this moisture turns to condensation and collects on rafters and other wooden surfaces.

The droplets then fall and can seep through the ceiling, causing the appearance of a roof leak. The water can also put your ceiling rafters at risk for developing rot, mildew, and harmful mold.

Exhaust Fans

Exhaust fans, like the ones typically found in bathrooms, aren’t usually vented to the outside—they vent straight into the attic. As warm moist air from the bathroom is exhausted into the attic through the ventilation system, condensation can form and turn to frost or ice, then drip down in what appears to be a roof leak.

Compromised Flashing

Flashing is a vital component of a sturdy roof. It covers seams and gaps, like where the roof meets the chimney to form a seal that prevents water from leaking through. If your flashing is damaged or cracked, melting snow or ice can leak through the imperfections, causing a leak.

Clogged Gutters

Roof gutters full of ice after a winter storm
Photo: JJ Gouin / iStock / Getty Images Plus / Getty Images

If all those autumn storms blew through and left your gutters full of leaves, sticks, and other debris, water from snow and ice melt has nowhere to go. As with ice dams, the water can push back under shingles and seep through into the attic and eventually down walls or through the ceiling.

How to Deal With Winter Roof Leaks

The key to winter roof leaks is prevention. Clean your gutters before temperatures drop and remove all the debris leftover from storms and rain so snowmelt has a way to escape the roof. You’ll also want to ensure your attic is well-insulated to avoid condensation formation.

If you already have water seeping in through the ceiling or down the walls, it’s time to call a professional local roofer to have a roof inspection. They can check the integrity of your shingles and your flashing for damage and give you an estimate for repair. 

Unfortunately, roof inspections in winter are tricky, especially in cold climates. Rooftop snow and ice make for a hazardous climbing environment, so this one is better left to the professionals rather than a DIY project. Also, aim to get your roof checked out before the seasons change to hopefully prevent the problem altogether.

If, during the inspection, ice dams, damaged shingles, or compromised flashing are found, professional emergency roofers in your area can repair the issue.

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