Ice dams sneak into a home silently, on a winter day, as a build-up of snow sits on a house’s roof. In this stealthy scenario, while the temperature outdoors drops to below freezing, the temperature inside the attic is above freezing. The villain here is heated air rising from the home’s living space, escaping upward where it shouldn’t. The heated attic air warms the roof.
The heated roof causes the blanket of snow on top of it to start melting from the bottom up, and rivulets start trickling downward. The melted snow water tries to flow down and off the roof. However, when the water emerges at the edge of the roof, it’s exposed to the freezing air, and the water refreezes.
Where the water was once snow at the peak of the roof, it’s now ice along the eaves and gutter area. As this melting and freezing cycle is repeated, the water has nowhere to go. It is trapped behind -- and on top of -- the previously frozen deposits, and the ice dam grows.
Trapped water doesn’t freeze immediately. In the meantime, house materials that come in contact with it are soaked, resulting in interior water damage. Unless corrective steps are taken, the water problem can recur, along with continued heat loss along the pathways that allowed the heated air to escape in the first place.
Members of the Milwaukee/NARI Home Improvement Council, Inc., the area’s leading home improvement and remodeling industry resource for more than 48 years, suggest the following tips to prevent ice dams.
As Tom Topping, sales manager at BCI in Menomonee Falls, points out, “You can’t totally eliminate freeze and thaw cycles. The goal is to manage the situation so it doesn’t cause damage. You’ll still get some icicles, but we try to work with Mother Nature rather than fight her. The big things are to properly install an ice and water shield, have proper ventilation in your attic, and have good insulation.” Topping adds, “Get your insulation evaluated, and look for areas where heat is escaping from the living space into the attic. It’s a critical item if your attic is getting too hot.”
Juan Hurtado, project manager at INTEC, Insulation Technologies, Inc. in Milwaukee, advises homeowners to take advantage of diagnostic tests performed by home energy auditors and home performance contractors.
“People think it’s the roof itself that’s going bad, but the problem is actually caused by bypasses, which are cracks. There is no one perfect solution, because each house is such an individual case,” Hurtado notes.
He says home energy auditors and home performance contractors can run a “blower door test,” using a huge fan hooked up to a house door. The air flow can pressurize or depressurize the air in the home. A pressure gauge reader helps determine how leaky the house is by recording the pressure reading in the home.
Also, Hurtado mentions, infrared cameras are used to show homeowners the air paths, cold points in the attic, voids in the insulation, and other bypasses in their houses.
Steve Sennholz, president of S&E Insulation in Shorewood, also recommends homeowners hire a professional to conduct an energy audit. “The high-tech world has changed insulation big-time,” he emphasizes.
The solution is not to simply add more and more insulation to a house, Hurtado and Sennholz agree, but to pinpoint with diagnostic tests where the bypasses are, and strategically solve the problem.
Sennholz observes that one house alone could have 40 leaky areas. Insulation options for various uses can range from fire-retardant foam board to fiberglass insulation to dense-pack cellulose to spray insulation to fill cracks, among others.
Sennholz adds, “Rebates are available for energy audits, and a tax credit is available.”
A qualified contractor is a good source of practical information on these homeowner incentives, he adds.
Myths About Ice Dams
While winter weather is beyond control, sorting out fact and fiction can help homeowners navigate a problem. Below are some myths and realities about ice dams.
Myth 1: Sun shining on a roof raises the exterior roof temperature enough to start runoff that leads to an ice dam.
Reality: With rare exceptions, sun exposure in the winter has little effect on attic air temperature. Warm interior air from living spaces below is usually to blame.
Myth 2: Only old houses are plagued with ice dams.
Reality: New construction can fall victim, too.
Myth 3: The west side of the house, warmed by afternoon sun, is afflicted the most.
Reality: All sides of the house are vulnerable.
Myth 4: It’s effective to chip away at ice dams and remove snow from the shingles.
Reality: Be wary of chipping. Since roofing materials are more brittle in the winter, shingle damage can result. To drain the ponding water, hire a contractor to create one or two grooves in the ice dam for runoff. A contractor can carefully remove most of the snow from the roof above the ice dam.
Myth 5: If you clean the gutters in the fall, it will prevent ice dams.
Reality: Keeping the gutters clean of leaves will not prevent ice dams.
The Milwaukee/NARI Home Improvement Council was chartered in July 1961, as a Chapter of the National Home Improvement Council. In May of 1982, the National Home Improvement Council merged with the National Remodelers Association to form NARI – the National Association of the Remodeling Industry.
The Council’s goals of encouraging ethical conduct, professionalism, and sound business practices in the remodeling industry have led to the remodeling industry’s growth and made NARI a recognized authority in that industry. With over 900 members, the Milwaukee Chapter is the nation’s largest.
For more information or to receive a free copy of an annual membership roster listing all members alphabetically and by category, and the booklet, “Milwaukee/NARI's Remodeling Guide,” call (414) 771-4071 or visit the Council’s Web site at www.milwaukeenari.org.
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