Ice Dams: What are they and how to prevent them.

marie60881
Feb 9
2 min read

For many homeowners, the sight of glistening icicles hanging from the eaves feels like a winter wonderland. But behind that postcard-perfect view often lurks a destructive force: the ice dam.

If left unchecked, ice dams can cause thousands of dollars in damage to your roof, attic, and interior walls. Here is a breakdown of why they happen and, more importantly, how to stop them before they start.

What Exactly Is an Ice Dam?

An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow from draining off. The water that backs up behind the dam can leak into a home and cause damage to walls, ceilings, insulation, and other areas.

How They Form: The Physics of a Leak

Heat Loss: Heat escapes from your living space into the attic.
Melting: This heat warms the roof deck, melting the bottom layer of snow on your roof.
Runoff: The meltwater flows down the roof until it reaches the eave (the overhang), which is much colder because it isn’t above the heated attic.
Freezing: The water freezes at the eave, creating a "dam."
The Leak: As more snow melts, water pools behind the ice ridge. Eventually, it finds its way under the shingles and into your home.

Immediate Fixes (The Band-Aids)

If you already have a massive ice dam forming, you need to act fast, but be careful. Never climb a ladder in icy conditions or use a chainsaw or hammer on your roof; you’ll likely damage the shingles (or yourself).

The Roof Rake: Use a long-handled roof rake to pull fresh snow off the first 3–4 feet of your roof. No snow means no fuel for the dam.
The Stocking Trick: Fill a nylon stocking with calcium chloride ice melt (not rock salt!) and lay it vertically across the dam. It will melt a channel through the ice, allowing the trapped water to drain safely.

Permanent Prevention (The Real Cure)

The secret to preventing ice dams isn't a better shovel; it's a cold roof. You want the temperature of your roof deck to be as close to the outside temperature as possible.

Boost Your Insulation: If you can see your attic floor joists, you likely need more insulation to keep heat in the living space.
Seal Air Leaks: Check for gaps around plumbing stacks, recessed lights, and attic hatches where warm air escapes.
Improve Ventilation: A combination of ridge and soffit vents creates airflow that keeps the roof deck cool.
Install a Water/Ice Shield: Ensure your next roof includes a waterproof underlayment extending at least 3–6 feet from the eaves.

Don’t Wait for a Drip—Call the Experts

Preventing ice dams requires a professional eye to ensure your ventilation and insulation are working in harmony. If you suspect your home is at risk or you've already spotted signs of a leak, it’s time to call in the pros.

For expert inspection, repair, and long-term prevention strategies, contact Covered Construction Company. They have the experience to keep your home dry and your roof healthy all winter long.