Identify Ice Dams in Your Home

Do the icicles on your home have something to tell you? Yes, and it’s not about how pretty they are. They can be a sign of ice dams.

Ice dams form when heat escapes through your ceiling and melts snow on the roof. Over time, this melting water can form a thick layer of ice at the edge of your roof where the temperatures are colder and keep water from draining properly. This can cause water to seep under shingles into the attic, causing damage to roof decking, joists and insulation.
How can you tell if you have ice dams? Here are a few quick tips:

• Do you have icicles? Not all icicles mean ice dams, but here are the things to watch for:

  • Ice forming on the siding/exterior surfaces of your home
  • Ice and icicles forming along the overhangs of your roof
  • Ice filling your gutters
  • Icicles forming with thick bases along the edge of your roof
  • Icicles forming a ridge along the edge of your roof
  • Icicles that are brown or yellowed. This is an indication that water has seeped under the shingles
  • Generally, the larger the icicles that form, the more likely they are to create an ice dam

• Is there water running down your house? Water dripping down your siding or dripping from the underside of your roof where it overhangs the house is a sign that ice could form and lead to an ice dam.

• Do you see water stains or moisture inside your attic of home? The presence of water stains or moisture along the ceiling of your attic, or along the ceiling of exterior walls can indicate that you have an ice dam and that water has been able to penetrate your home through the roof. 

Would you leave your window open all winter? If you see ice dams on your roof, you could be losing the same amount of heat and energy. 


Posted February 2019. Updated December 2019.

Ice Dam Photo

Home Performance with ENERGY STAR