Winter Roof Leaks: How Ice Dams in Roof Valleys Cause Major Damage
Why Roofs Leak More During Cold Weather
Winter weather creates conditions that dramatically increase the risk of roof leaks—especially in areas with freeze–thaw cycles like Dallas–Fort Worth. When temperatures drop, frost, sleet, or light snow can melt during the day and refreeze overnight. This process often leads to ice dam formation, particularly in roof valleys and along eave edges. Once ice dams form, water can no longer drain properly, and it begins to back up underneath shingles and into your roofing system.
Roof valleys, low-slope sections, and shaded areas are the first places to develop cold-weather leaks. Even newer roofs can experience water intrusion if the ice dam becomes large enough. Missing shingles, exposed nails, aging underlayment, or poor attic ventilation make winter leaks even more likely. That’s why cold weather often reveals weak points in a roofing system that went unnoticed during warmer months.
Ice Dams Explained
How Ice Dams Form and Why They Lead to Roof Leaks
Ice dams occur when heat from inside your home warms the roof deck, causing the snow or frost above it to melt. As the water flows down toward colder areas—especially roof valleys—it refreezes and creates a barrier of ice. With nowhere to go, the trapped water begins to work its way underneath shingles, through underlayment, and even into roof decking. This leads to interior leaks, stained ceilings, moisture-damaged insulation, and long-term structural issues.
Homes with deeper valleys, inadequate ventilation, or older roofs face the highest risk. The best prevention involves proper ventilation, sealed valleys, and modern ice-and-water barriers. A winter roof inspection can identify vulnerabilities before ice dams cause expensive damage.