When are Icicles a Problem?

Icicles and ice dams on formed on the roof of a house.

Icicles….Don’t be fooled by their glittery appearance!

Hanging from the eaves of a house, icicles may look beautiful, but they spell trouble. When an icicle catches your eye, you can bet there’s something ugly hiding behind it. Ice damming.

Ice dams are caused when solar heat from above, and heat loss from beneath, warm a snow covered roof. Melted snow trickles down to the eaves, overhangs and valleys, (which are typically colder than the rest of the roof). When temperatures dip below freezing again, the melt water refreezes, forming dams of ice. If enough ice builds up, any further melt water coming down the roof pools up behind and can get under the shingles and into your house. When that happens, the results can be soggy attic insulation, stained ceilings and peeling paint.

Some roofing configurations are more prone to ice damming than others. Most common are low slope roofs or roofs which change from a high slope to a low slope.

The best way to stop ice damming is to keep the entire roof as cold as the eaves. Ventilating the attic space should include soffit vents, soffit baffles and roof vents. The current standard for attic space insulation is R 50. The attic access door is a common area of heat loss as well as air leakage around ceiling light fixtures. Improvements (air sealing) prevent air movement from a heated zone the cold zone may improve home comfort and reduce energy use.

Now, enjoy the beauty of the season knowing when an icicle is twinkling at you, it’s from your neighbors house!