Icicles and Ice Dams
Over the past week here in Chicagoland, street after street you can see icicles hanging from homes – new homes, old homes, townhomes, and even commercial buildings are “decorated” with icicles.
While considered beautiful by some, icicles may indicate trouble. But not all icicles are problematic. This past week we have had rain, followed by snow, followed by even heavier snow. The last snowfall was markedly heavy, wet snow.
As a result, we are seeing an unusually high number of buildings with icicle formations. Even brand new homes, yet to be completed have icicles hanging from the roof. This is rare and due to the density of the wet snow on the roof. Typically, snow melts into water that runs quickly down the roofline to the gutter and out throughout the downspout.
Heavy soggy snow combined with sub-freezing temperatures turns into slush. Slush doesn’t run off like water as it moves down the roofline, instead, it slides slowly down the roof and freezes into elongated icicles as it drips off the edge. Icicles harden during the cold night temps. When exposed to sunlight, the outermost layers begin to slowly melt, then freeze again.
When to be concerned
Icicles can pose both safety and structural dangers. Icicles can be very sharp and are often much heavier than they appear. Falling icicles can cause bodily harm to humans and animals. Be aware of icicles above doorways, garage doors, and around porches.
If slush fills the gutter and freezes, it can block gutters and downspouts, forcing ice and water to overflow and push up under nearby shingles causing what is called an ice dam. Ice dams left unaddressed can lead to costly structural damage. Learn more about Ice Dams here.
What can you do?
Use a roof rake to break off icicles and remove slush and snow from accessible rooftops. Be very careful of falling ice! If you don’t have a roof rake or are not inclined to rake your roof, hire someone to do it for you. Or just wait for icicles to melt as temperatures rise.
Be sure to inspect your attic and ceilings for signs of water damage after heavy snow. Older roofs with existing damage can easily fail under the weight of heavy wet snow.
If you have blocked gutters – it may be worth it to hire someone to come out and unblock gutters and downspouts, to prevent significant roof damage from ice dams.