Icicles Are Not Cute: What Ice Dams Are Telling You

Pretty on a postcard, trouble on a roof

Icicles hanging from your eaves look charming. They are also a hint that heat is escaping from your house into the attic, and that is the root of ice dams.

How an ice dam forms

1. Heat from your house leaks into the attic and warms the roof
2. Snow on the roof melts
3. The water runs down to the cold edge of the roof, where it refreezes
4. A ridge of ice builds up, and new meltwater backs up behind it

Shingles are built to shed water, not to stop it when it is standing. Backed-up water can sneak under them and into the roof, ceiling or walls. A dam can also weigh down gutters and tear them loose.

Fix the cause, not just the ice

Chipping at ice is hard on your roof and gutters. The lasting fix is to keep the roof cold, in this order:

1. Air-seal the attic floor. Gaps around top walls, wire holes, bath fans, hatches, recessed lights and duct boots let warm air escape.
2. Insulate well. Cold climates need a lot, and baffles keep the insulation from blocking the vents at the eaves.
3. Ventilate. Cold air enters low at the soffits, warms up, and exits high at the ridge. You want more intake than exhaust.

The mantra: seal first, insulate fully, then vent.

How gutters fit in

Gutters do not cause ice dams, but they can be where the damage shows up. Clogged gutters hold water that freezes into thick ice, and the weight can bend hangers and pull gutters away from the house. Clearing gutters before winter gives melting snow somewhere to go.

What we do and do not do

To be clear, we do not do snow removal, roof raking or ice-dam steaming. We focus on keeping gutters and downspouts clear and working, and we are happy to point out roof-edge problems we spot while we are there.

Signs to watch for

• Big icicles, especially in some spots and not others
• Ice built up along the roof edge or behind the gutter
• Water stains on ceilings or walls near exterior walls
• Frost on the underside of the roof deck in the attic

For attic work, an insulation or weatherization contractor is the right call.

Need your gutters ready before the next freeze? Request an estimate and we will get you on the list for spring.