How Clogged Gutters Cause Ice Dams
A clogged gutter causes ice dams by holding wet leaves that freeze into a solid plug at the eave. When snow on the roof melts — from attic heat or a sunny afternoon — the water runs down and hits that frozen plug, backs up under the shingles, and refreezes. That ridge of ice is the dam, and the water pooling behind it finds its way through the roof and into the ceiling.
Chicago O'Hare averages 38.4 inches of snow a year, so there's plenty of melt-and-refreeze cycling through an Oak Park winter. A gutter packed with December leaves gives that melt nowhere to go.
Why Oak Park Homes Are Prone to Ice Dams
Oak Park homes are prone to ice dams because of their age and their trees. With 59.3% of homes built in 1939 or earlier, many have the modest attic insulation and ventilation of an older house, which lets more roof heat escape and melt the snow above. Add the nearly 18,000 parkway trees dropping leaves into the gutters right up to winter, and you have the two ingredients for a dam: warm roof melt and a blocked, frozen gutter.
The older fascia and trim on these homes is also what suffers. Water backing up behind a dam soaks into wood that has already weathered decades of Chicago freeze and thaw.
What to Clear Before Winter
First, clean the gutters after the leaves are down but before the first hard freeze — mid-to-late November in Oak Park. Second, flush the downspouts, because a frozen, full downspout has nowhere to send any thaw that does get moving. Third, have any sagging runs or loose hangers fixed, since a run that already ponds water freezes first. A gutter repair visit before winter catches the sag that a dam would anchor to.
Clearing the gutters is one part of ice dam prevention; attic insulation and ventilation are the other, because they keep the roof cold enough that less snow melts in the first place. For gutter clearing before winter in Oak Park, call 123-456-7890.
