Winter Damage On Roofs: Beyond Weight Damage

Posted on: 21 November 2014

When people think of winter damage to roofs, they mostly think of destruction due to the weight of snow and ice. Unfortunately, this is not the only way that winter can reduce your roof's durability. Other ways in which the low temperatures can damage your roof include the following:

Freeze-Thaw-Freeze Cycle

During a snowfall, the first layer of snow melts because the roof is relatively warmer than the environment above it. This melting snow gets into cracks and crevices on the roof. Then as more snow falls, the water in these cracks and crevices freeze, and this is where the problem begins.

As you know, water expands when it freezes, so the freezing water will expand and enlarge the cracks on your roof. On a subsequent warm day, the snow and ice melt to fill the enlarged crevices. If more snow falls on the roof, the whole process repeats itself. A vicious freeze-thaw-freeze cycle is then formed, and the cracks in your roof widen with each complete cycle. Pretty soon you will be dealing with a roof leak.

Thermal Shock

Apart from the freeze-thaw-freeze cycle, winter conditions can also damage your roof due to thermal shock. Most solids, such as those used on your roof, expand when heated and contract when cooled. Unfortunately, rapid expansion and contraction (occasioned by temperature fluctuations) makes the materials lose their tensile strength.

This is known as thermal shock, and it is what happens when temperatures fall and rise rapidly during winter. The roof materials suffer thermal shock and weaken, meaning they may not be able to withstand further stress, for example, from strong winds or accumulation of snow on the roof.

Thermal shock is more pronounced in:

  • Aged roofing materials
  • Roofs with multiple materials (different materials expand and contract differently)
  • Roofing materials that are poor conductors of heat (such as rocks and ceramics)


One way of preventing winter roof damage is to install a reflective roof. If you already have a roof in place, then you can paint it white to reflect most of the heat. That way the materials won't expand or contract as much because they won't absorb a lot of heat.

Additionally, you should deal with the snow on your roof by installing adequate drainage on your roof and removing snow or ice before they accumulate to dangerous levels. This is to prevent the freeze-and-thaw cycle.

You may not be able to prevent all forms of winter roof damage. Therefore, you should have your roof inspected by roofers before and after the winter season. The first inspection is to identify and strengthen any weak points, while the second one is meant to identify and repair the damages.