The winter season brings many perils that can damage any property. From falling trees and debris due to high winds and heavy ice from wither storms to frozen pipes to floods from melting snow and ice – winter’s wrath can be very destructive. However, there is another damaging situation that occurs even long after the cold of winter gives way to spring – ice dams.
An ice dam (or ice jam) occurs when water builds up behind a blockage of ice. Ice dams can occur in various ways, such as ice blockages of gutters and spouts on buildings.
Once an ice dam forms, the only relief is to remove the ice and snow from the roof. This extremely dangerous work should be left to qualified professionals with the right training and tools. Improperly done, the roof can be severely damaged.
Ice dams are caused by the interaction of three factors:
- Fluctuating Temperatures – Ice and snow melt at 35°F; liquid water freezes at 32°F. Minor temperature differentials can lead to major problems.
- Roof Structure – Layered roof systems such as shakes or shingles do not keep out standing water. They require a continuous, uninterrupted slope to shed water.
- “Warm” Attics – Attics are warmer than the outside air because heat leaks from the heated portion of the structure up into the attic. Heavy snow cover effectively insulates the attic from cold outside air, allowing the temperature to rise even higher.
Eventually, the temperature of the roof under the snowpack, usually near the ridge, rises above the melting point. Melted water runs down the roof, refreezing when it reaches the edge of the insulating snow blanket at the eaves. They are still far below the freezing point since they are unheated by air from the structure interior, causing an ice dam to form.
As layer after layer of melted water refreezes, the ice dam grows, and liquid water pools behind it under the snow. Soon, this water is deep enough to seep between shingles and into the attic or wall cavities. Ice dams can be one to two feet thick. Secondary ice dams often form around vents and skylights.
Ice dams cause millions of dollars of damage every year. Obvious, visible damage may include:
- Sagging, ice-filled gutters
- Delaminated or rotted roof decking
- Stained, sagging wall or ceiling drywall
- Damaged and/or dislodged shingles or shakes
- Wet insulation (both temporary and permanent problems)
Unfortunately, obvious damage may be just the tip of the iceberg. The worst effects of ice dams are often hidden, caused by moisture trapped inside walls or floors. This damage is seldom discovered until months after all the snow has melted.
Aside from the cost of restoration, hidden damage can make future ice damming more severe, waste energy, and even create serious health risks for building occupants.
If one of your policyholder has been affected by an ice dam, Call Paul!
Call Paul Davis at 801-299-1000.
