Preventing Ice Dams



Ice dams occur when ice and snow that build up along the roof melt during the day, and then refreeze when temperatures drop overnight. It is common for this water and ice to work up under shingles, eventually causing damage to the ceilings, wall and contents.

There are steps you can take to reduce the risk of ice dam formation:

  • Clean all leaves, sticks and other debris from your gutters and down spouts. This lets melting roof snow flow into gutters and through down spouts, just as they were designed.
  • Minimize the amount of snow on your roof. Hire a professional contractor to remove the snow or, for do-it-yourselfers, purchase a “snow roof rake,” which lets you stand at ground level and pull snow off the roof. Keeping heavy snow loads off your roof reduces the chances for both ice dam formation and roof failure due to the weight. If you don't have access to a roof rake, you may want to consider this do-it-yourself project which tells you how to make a roof rake from PVC.
  • Seal vent pipes, chimneys, attic hatches, wiring, exhaust fans, light fixtures and any place that would allow warm air to leak from the interior rooms into the attic. Use silicone caulk, foam sealant or other similar products to stop the air flow around these areas.
  • Install electrical heating cables/tape in gutters and along roof edges.
  • Install an ice guard membrane under the first three to four feet of shingles.
  • Install or improve the vents in your roof.
  • Evaluate attic insulation and ventilation. Experts agree the R-value of insulation should be at least R-30 (R-38 is preferable in northern climates).
 

If You See Ice Dams

If you do get ice dams along your gutters, here are some tips:


Do
  • Remove snow from your roof and gutters using a roof rake or push broom by carefully pulling the snow down vertically. Melt built-up ice dams using calcium chloride tablets.
  • Chisel out grooves in the dam to allow water to flow through. Use caution not to damage the roof or gutter.
  • Use extreme caution when using a ladder.
Don’t
  • Climb, walk or stand on your roof!
  • Remove your gutter from the house. This will result in further damage.
  • Pull snow and or ice horizontally across your roof. This can damage the roof shingles.
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