How do ice dams form and what is the best way to stop them?

Ice dams form when heat escapes from your home into the attic and warms the upper part of your roof surface. This heat causes the bottom layer of snow to melt and run down toward the colder eaves where it refreezes into a thick barrier of ice. This barrier traps liquid water behind it. The trapped water then forces its way under your shingles and into your home. You can prevent this by maintaining a "cold roof" through proper attic insulation, consistent ventilation, and clearing heavy snow with a roof rake.

Why Chicago Homes are Especially Vulnerable

Our local climate in the Chicago suburbs creates the perfect storm for ice dams. We often experience heavy snowfall followed by a week of sub-zero temperatures. This is often followed by a rapid "sun-thaw" during the day. This cycle is exactly how ice dams grow thick enough to pull gutters off of a house. According to building science data from the University of Minnesota Extension, even a minor temperature difference of just a few degrees between your roof peak and your eaves is enough to trigger this destructive process.

The Hidden Damage You Cannot See

Most homeowners only worry when they see a leak in the ceiling. However, the damage often starts much earlier. When water stays trapped behind a dam, it can cause several issues:

  • Saturated Insulation: Wet insulation loses its R-value. This means your furnace has to work harder and your energy bills will skyrocket.

  • Structural Rot: Constant moisture against the plywood roof deck can lead to wood rot that compromises the strength of your roof.

  • Mold and Mildew: Damp walls provide the perfect environment for mold to grow behind your drywall. This often goes unnoticed until the smell becomes apparent.

Long Term Prevention: The Three Pillars of Roof Health

To truly solve an ice dam problem, you must move beyond temporary fixes like salt pucks or heat tape. You should focus on these three professional standards.

1. Strategic Air Sealing
The most common cause of a warm roof is "bypass" leaks. These are small gaps where warm air from your kitchen or bathroom leaks into the attic. Common culprits include recessed lights, plumbing stacks, and the attic hatch itself. Sealing these gaps is the first step in keeping your roof deck cold.

2. High-Performance Attic Insulation
Illinois building codes have updated requirements for insulation thickness. If your home was built more than fifteen years ago, you likely do not have enough insulation. Upgrading to a higher R-value ensures that the heat you pay for stays in your living room rather than escaping through the roof.

3. Balanced Ventilation Systems
A roof needs to breathe. Intake vents at the soffits must work in tandem with exhaust vents at the ridge. This constant flow of air flushes out any heat that manages to escape into the attic. According to GAF Roofing, a balanced ventilation system is the single most important factor in extending the life of your asphalt shingles.

Frequently Asked Questions

Can I use a pressure washer to remove an ice dam?
No. You should never use a pressure washer or a hammer to remove ice from your roof. High pressure water can strip the protective granules off your shingles. A hammer can easily crack shingles that are brittle from the cold. Professional contractors use low pressure steam to safely melt the ice.

Are gutters the cause of ice dams?
Gutters do not cause ice dams. However, if your gutters are clogged with leaves, they can make the problem worse by preventing meltwater from escaping. Clean gutters are a secondary defense, but they cannot fix a poorly insulated attic.

Does my homeowners insurance cover ice dam damage?
Most standard policies cover the interior damage caused by a leak. However, they rarely cover the cost of the roof repair itself or the professional removal of the ice. Prevention is always more affordable than a claim.

When to Call the Experts at Stan's

If you are currently dealing with massive icicles or water spots on your ceiling, do not wait for the spring thaw. Our team understands the unique architecture of Chicagoland homes. We can evaluate your attic and provide a permanent solution to keep your home dry and energy efficient all winter long.

Sources:

  • University of Minnesota Extension: Dealing with and Preventing Ice Dams.

  • Insurance Institute for Business & Home Safety (IBHS): Reducing Ice Dam Risks.

  • GAF Technical Bulletin: Ventilation and Shingle Performance Standards.