Frozen gutters and downspouts: what to do this winter

When gutters and downspouts freeze solid, don't chip at the ice or climb an icy ladder. Knock icicles down from the ground only if nobody is below, clear the downspout discharge so meltwater can escape, and let warm spells do the work. If water is coming indoors, call a roofer. Prevention starts in fall with clean, flowing gutters.

Why do gutters freeze solid?

Ontario winters swing above and below zero again and again. Every thaw sends meltwater off the roof, and every cold snap freezes whatever did not drain. A gutter full of leaves holds water like a sponge, a low spot holds a pool, and a downspout on a shaded north wall freezes at its bottom elbow first. Layer by layer, the trough fills with ice, and once the outlet is frozen, the next thaw's water has nowhere to go but over the edge, or back under the shingles.

Is a frozen gutter a problem?

• Weight: a metre of 5-inch gutter full of ice weighs roughly ten kilograms, and hangers were not designed for a winter of it.
• Ice dams: a frozen gutter gives the ridge of ice at the eave its foundation. Ice damming explained.
• Water indoors: meltwater backing up behind the ice can get under shingles and into the house.
• Icicles: heavy icicles over doors and walkways are a hazard in their own right.
• Ice at the discharge: water running from a downspout can freeze into a sheet across a walkway.

What is safe to do right now?

1. 1Stay off ladders and roofs in icy conditions. No gutter is worth the fall.
2. 2Clear snow from around downspout outlets and extensions so meltwater can run away from the house when it thaws.
3. 3Keep walkways under icicles clear, and knock down dangerous icicles from a safe distance with a long pole only if nobody is below.
4. 4Use a roof rake from the ground to pull the first metre or so of heavy snow off the roof edge, gently, without scraping the shingles.
5. 5Watch the ceilings and walls along exterior walls upstairs for stains after a thaw.
6. 6If water is coming in, call a roofer who does ice dam removal; they use steam equipment that melts ice without damaging the roof.

What about a downspout that is frozen solid?

Leave it until a thaw. A solid downspout will clear itself as temperatures rise, as long as the water can escape at the bottom, so make sure the extension and outlet are clear of snow and ice. If the same spout freezes solid every winter, look at why: a shaded north wall, an extension that holds water, or a partial clog that slows drainage in fall. A larger downspout or a targeted heat cable can fix a chronic one.

In Toronto, remember that a disconnected downspout's water must not create dangerous icy conditions on walkways. The Toronto bylaw covers discharge rules.

What should you check after the thaw?

• Runs that sag or have pulled away from the fascia. Sagging gutters.
• Seams and corners split by ice, which drip even in light rain. Leaking seams.
• Downspouts crushed, split or pulled from their straps.
• Stains on fascia and soffit where water backed up behind the gutter.
• Shingle damage at the eave where ice built up.

How do you stop it happening next winter?

1. 1Clean the gutters in late fall, after the final leaf drop, so they go into winter empty and draining.
2. 2Flush every downspout and make sure extensions carry water 1.5 to 2 metres away.
3. 3Fix low spots and loose hangers before the freeze, so water drains instead of pooling.
4. 4Have the attic's insulation and ventilation checked if ice dams keep returning; that is where they start.
5. 5Consider heat cables only for the specific spots that freeze every year.

Why are North York's ravine lots hit hardest?

North York's ravine-backing lots, from Bayview Village to York Mills, have rear eaves that sit in shade most of the winter, with oak and ash debris on top of the maple leaves that line the older streets. A north-facing rear gutter that went into November full of leaves is exactly where ice builds first and thaws last.

The fix starts now, before the freeze: a late-fall cleaning with every downspout flushed and flow-tested. Downspout service in North York includes clearing blockages and checking where each spout discharges, and ice-damaged hangers and seams can be fixed in spring, from $89, priced on site and approved first.