Winter and Your Roof- Thermal Shock

weather during winter, but luckily during most of our day we are protected by buildings.  Think of what it’s like out there on your commercial roof.  Sadly, winter is one of the roughest things your roof will face.  And, it does it for months on end.

Temperature Fluctuations

Your roof temperature fluctuates all year round.  The temperature difference between the peak daytime heat and the cold of night can wreak havoc on your roof.    This phenomenon is known as thermal shock.  Over time, thermal shock is a leading cause of roof failure.

What makes winter potentially more destructive than summer, is what comes along with cold weather:  ice and snow.

All objects expand and contract as they heat and cool.  But, they expand and contract at different rates. So, the wood, steel, brick, and asphalt are expanding and contracting at different rates.  This process causes stress on the joints where different building materials meet, as they don’t all expand and contract together.  Thus, small cracks and holes will form over time at these stress joints.

Now add water.  Well not just water, but snow that will melt slightly during the warm day and then freeze again overnight.  That tiny stress crack where the expanding materials meet is now filled with ice.  As the ice expands, it makes that tiny crack larger.  Over time it becomes larger and larger and larger.  That happens all over your commercial roof.  Eventually leaks result.


Ice Dams

Ice dams are layers of ice that form around drains or at the edge of your roof during the winter.  They keep the melting snow from properly draining off your roof. The water that forms behind an ice dam will add an additional load to your roof, potentially resulting in collapse.  Also, the water trapped by ice dams will leak through any damaged areas in your commercial roof.

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What Can You Do?

You can take several steps to prevent or minimize the impact of cold winter weather on your roof system.

  • Perform a comprehensive roof check at least twice a year.  Look for dark spots on the roof which might indicate ponding water problems.  Level any low spots on your commercial roof to reduce ponding water.  Check all penetrations, flashings, drains and joints in your roof system for signs of separation or other damage.  Properly seal any cracks or holes.
  • Keep all drains and gutters free of debris.  Leaves and other natural debris can clog drains and cause ice dams to form.
  • Improve your insulation.  Keep internal temperatures more constant and minimize heat loss which can affect thermal shock.
  • Use heat cables. If your commercial roof is susceptible to ice dams, install heat cables in gutters and drains.
  • Invest in a white roof.  A white or reflective roof system can reduce thermal shock by reducing excessive temperature fluctuations.
  • Use a silicone roofing system.  Commercial silicone roofing products have been around for decades and have proven themselves to be more durable to environmental factors.  Read this article to learn more about silicone commercial roofing systems.
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