What Is an Ice Dam?

An ice dam occurs when snow partially melts off of a roof and refreezes in the gutters. The more water there is to refreeze, the thicker the block of ice becomes. As more snow melts, the water has nowhere to go. This ultimately leads to the water pushing up and underneath the roofs shingles which can wreak havoc on the eaves.

Damages Caused by Ice Dams

If left unattended, ice dams can trap a large amount of melting snow. Since this water has nowhere else to go, it inevitably pushes underneath the shingles of the roof. When this happens, not only the shingles but the felt roof paper and wood sheathing can be destroyed. All it takes is one winter for this process to substantially ruin the eaves of a roof.

How to Prevent Ice Dams

If ice dams form on your gutters, the ice needs to be melted immediately to allow the water behind it to escape. This can be done with rock salt or an ice melter. If the roof is properly ventilated at the ridge and the under-eaves or soffits, adequate outflow of air typically prevents ice dams from ever forming.

Ice dams can cause a lot of damage to a roof in a hurry, so it is better that they never be allowed to form.