Ice Damming 101 – Part One

By Evelyn Witterholt. 

Learn what exactly ice damming is and what kind of damage it can do to a roof. 

Homeowners who live in colder climates need to know about the problem of ice damming. Ice dams occur during the winter when snow from the ridge of a roof melts and the water builds up and freezes at the eave of the roof. The snow melting is caused by heat loss occurring on top of the roof when it gets too cold. 

The eaves of a roof are the coldest part of the roof, hence why the run-off water from the melted snow can settle there. According to TRA Snow & Sun, “When you have water refreezing on the roof’s eave and more water coming in behind it, that water either gathers behind in the warmer region of the roof where it can eventually lead to leaks and damage to the roof, or it travels over top of the ice dam creating icicles.   

Once created, an ice dam can go through several freeze thaw cycles. The National Weather Service says that when this happens, it’s quite common for melted water and ice to get under the shingles (or other roofing product). This can eventually lead to leaks in the ceilings and walls, especially if the ice dam goes unnoticed.  

TRA Snow & Sun says that besides leaks, there are other ways ice damming can cause damage to a home. Snow and ice sliding down a shed roof and causing the ice dam to tear away parts of the roof or its components such as – chimneys, electrical and plumbing penetrations, gutters, dormers, windows, etc.  

Stay tuned for Part Two of our ice damming series to learn how to prevent ice dams and what to do if your roof has ice damming. 

Photo credit: Concrete and Clay Tile Roof Design for Cold and Snow Regions