How to Clear Frozen Gutters and Downspouts

A gutter solid with ice can hold well over a hundred pounds per run, which is enough to bend the hangers and pull the fascia board off the wall. The ice is usually a symptom rather than the problem: the same attic heat loss that causes ice dams keeps feeding meltwater into a gutter that is below freezing. Thawing is a slow job done from the ground.

Take the snow off the roof above

Stop the supply first. A telescoping roof rake used from the ground clears the band of snow above the gutter that is melting and refilling it. Locate the overhead service drop and any power lines before raising the pole, and keep a metal rake away from them.

Dig out the bottom of the downspout

Check where the downspout discharges. If the outlet is buried in a plowed snowbank or frozen into a puddle of ice, the whole run refreezes no matter what is done above it. Clear a channel away from the outlet and give the water somewhere to run before thawing anything higher up.

Thaw a channel with warm water

Pour warm water slowly into the top of the downspout, or into the gutter at the outlet, and let it work its way through. It will open a narrow path the rest of the meltwater can follow. Work in stages and keep watching the bottom, since water dumped into a still blocked leader backs up and freezes again.

Feed heat cable into a blocked leader

For a downspout that stays plugged, a length of self regulating heat cable dropped down the leader and plugged into a protected outdoor outlet will open it over several hours. Use cable listed for gutters and downspouts and follow the maker's instructions on routing and outlet protection.

Keep the ladder and the chisel in the garage

Do not set a ladder on ice or snow, do not lean one against an ice filled gutter, and do not climb onto the roof. Never chip, hammer, or pry the ice out. Aluminum gutters dent and split under a chisel, and the seams open up and leak once the ice is gone. A roofing or gutter contractor with a steam rig can clear it without damage.

Before the first freeze next fall. Clean the gutters out, check that hangers are tight, and run downspout extensions several feet away from the foundation so the discharge does not pool and freeze at the outlet.

Do not blame the gutters. Gutters do not cause ice dams and taking them off does not prevent one. Fixing the attic heat loss is what stops both problems.