Ice Dams

Today we have a guest post about Ice Dams, from Marcy Tate over at Networx.com.

Ice Dam Damage and Infrared Inspection

Ice dams are one of the most common and damaging winter roof problems. Heavy snowfall, along with cold temperatures, can result in roof leaks. However, even more common than roof leaks are roof ice dams. Ice dams can damage the soffit area, roof sheathing, gutters and interior walls. Water from melted snow can also seep under the roof shingles and into the attic, causing additional damage. Serious rotting of the roof and in the attic can occur. Mold growth is another common problem resulting from ice dams.

Definition
An ice dam is a wall of ice or a row of icicles that forms at the edge of the roof, right at the gutters and overhang. Ice dams are dangerous because they are sharp and heavy and can fall on and injure passersby. They form when snow drips from a slanted roof and then freezes. The melted snow flows down the roof, under the un-melted snow, and then onto the eaves and into the gutters. Once the melted snow reaches the overhang and gutters, which are much colder than the rest of the roof, the water quickly turns into ice all along the overhang.

Cause
Ice dams are caused by poor attic insulation and poor attic and roof ventilation. Poor attic insulation results in a significant amount of heat leaving the home through the attic and roof. The heat makes the snow melt at a fast rate and causes ice dams. The fast melting snow becomes trapped under the heavy snow, causing leaks.

Prevention
The only way to prevent ice dams is by having the proper amount of attic insulation. Insulation shouldn't block roof ventilation. Inspectors should advise homeowners with ice dams to seal air leaks in the attic in order to prevent warm air leakage. Cleaning out the gutters before winter to remove any leaves or debris will also help decrease the severity of an ice dam if it does occur.

Inspection
In a typical buyers inspection, an inspector would not use an Infrared camera, but this is what might happen as part of a home energy audit, ordered by a homeowner. Thermal imaging (also called infrared inspection), using an infrared camera, can help inspectors detect the source of heat loss in a home. Heat loss is the number one cause of ice dams. A home with ice dam damage can be a red flag for prospective home buyers. Determining the extent of ice dam damage is crucial during a home inspection. Infrared inspection can instantly show active heat loss through the outer portion of the walls and ceilings. It can detect uninsulated areas where snow dams will likely occur. Infrared cameras can detect the following, all of which cause ice dams:

• Hidden dampness or leaks
• Missing, loose, or compressed insulation
• Air leaks into or out of the home
• Leaky or poorly insulated heating/cooling ducts

When inspecting a home that had ice dams, an inspector should pay close attention to water marks, drips and lines on ceilings and exterior walls. If fresh water marks are discovered, it can be an indication that ice dams have formed.

Advice for Homeowners
Many homeowners unintentionally cause damage to their roofs while attempting to remove snow and ice dams from the roof. Inspectors should advise homeowners to call a professional roofer to remove snow from the roof. Additionally, homeowners should never:

• Attempt to go up on an icy or snowy roof.
• Remove snow from the roof. It will likely lead to shingle damage.
• Attempt to chip away the icicles formed by ice dams. It will also likely lead to shingle damage.
• Use salt or calcium chloride to melt snow on a roof. These are corrosive and can shorten the life of metal gutters, downspouts and flashings.

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Written by Marcy Tate
Marcy is a home improvement blogger at Networx. She has been working with roofing contractors for over a decade.