Long Icicles Could Mean an Ice Dam

Hunt's Construction - Ice Dam

Icicles hanging off your roof are a good indicator that you have an ice dam on your hands.  Ice dams form when melted snow pools then re-freezes at the eaves of a roof (near gutters) and creates a clog of ice pulling shingles from the decking.

Preventing ice dams from forming is the best way to remedy them.  Ice and Water Barrier is typically installed on the eaves and valleys of roofs by building code.  If your roof was professionally installed then you should have Ice and Water Barrier.

Not only can large icicles fall, harming someone, but the cycle of thawing and refreezing can damage roofs and allow interior moisture into inner wall cavities.  Interior water damage can be costly.

The most common cause for ice dams is poor heat distribution in an attic. They also can form when gutters or downspouts are clogged with debris, not allowing the gutters to drain properly.

When a roof has an ice dam, water can find its way inside the interior walls of a home, into the sheeting (causing rotting of the plywood or OSB) and through the nail holes expanding and damaging shingles.

If icicles are common on your house – eventually, water can and will leak into your house!

Ice dams aren’t all bad news. They can be a useful diagnostic tool.  Mark Loscutoff, president of Omaha Home Energy Analysis and Testing, said ‘the melting and freezing patterns on your roof are clues that tell you where you’re losing heat’.

“If you have a nice, even covering of snow but there are some depressed spots as the snow melts, those depressions are specific points of heat loss that are melting the snow,” he said. “If it’s more of an even melting going on, it may be a shortage of insulation in the attic or it could be a lack of attic ventilation.”


Snow RakeIf you have an ice dam, the worst way to remedy it is to chip away the ice, because you will end up harming your roof. If you puncture through the shingles into the underlayment then you have permanently compromised the water-shedding ability of your roof.  A snow rake can help remove collected snow from low-pitched roofs before snow thaws and re-freezes.  Proper attic ventilation, unobstructed water removal systems (gutters) and Ice and Water Barrier also prevent ice dams.

You can thaw an ice dam in an emergency with a heat cable, which is a long cable that feeds through a pipe, drain or gutter.

Hunt’s Construction performs free roof inspections.  If you have a problem with icicles or ice dams then give us a call.  We can diagnose the cause and help you remedy it.

Chris Peters, staff writer for the Omaha World-Herald originally published this piece on Feb 20, 2019