This winter’s heavy snow is causing major problems for some Chicago-area homes. The thick coat of snow that remained for weeks on top of most homes has begun to melt. The result is that the melted snow is working its way into attics and eventually down into living spaces.
“It’s been a while since it’s been this bad. That’s because of the amount of snow we’ve had this winter,” said Bill O’Brien, past president of the Chicago Roofing Contractors Association.
Here’s what causes the problem, according to O’Brien: A lack of proper insulation and ventilation in an attic.
“When you drive by homes with no icicles, you know they’re well ventilated and insulated,” said O’Brien, a west suburban roofing contractor. When an attic isn’t properly ventilated, warmed air from inside a home’s living space escapes into the attic.
“That heated air rises up and warms the underside of the roof, which in turn begins to melt the snow on the peak of the roof,” said O’Brien. That melted snow runs down the pitched roof under a layer of snow.
As it reaches a cold gutter, it refreezes and begins to form into what’s known as an ice dam. As the snow continues to melt, that ice dam grows, climbing up out of the gutter. Meanwhile, icicles start to hang off the side of the house. Ice dams are especially likely to occur when there is a deep snow, which is followed by a freeze-thaw cycle.
Sunshine can also melt the snow. “This is where the damage starts,” O’Brien said. That ice dam can grow high enough so that it creeps up the roof and pushes up roof shingles. That allows water to seep into the attic, where it can damage insulation, bring on wood rot and also work its way down to the living space below.
What is especially troublesome is if the water gets behind walls, which not only damages the plaster or drywall finish, but also the wood support structures buried inside the walls. Outside, meanwhile, gutters start to sag and bend and can be twisted off of a building.
Unfortunately, there’s not much you can do about problems with snow on the roof.
“I don’t recommend that any homeowner go up on the roof and try to clear that snow and ice away,” said O’Brien. “It is extremely dangerous.”
If you have a one-story house, you can try to reach up from the ground and remove snow from the roof with a roof rake. “It’s difficult to do the same with a two-story house, although you can try to reach some of the snow through second-story windows,” said O’Brien.
You can also try to find a residential roofing contractor to come out and do the job. “Although most won’t do it because it is dangerous work,” said O’Brien. “If you find a company, make sure it is licensed and insured. And expect to pay about $400 to $500 on the high end for the job.”
A homeowner can also try to spread an ice melt product on the ice dam, but remember that some of these products might hurt the plant life below when it comes back to life in the spring.
Although it’s a more expensive solution, homeowners should also consider venting and insulating the attic space. Not only will such a project keep ice dams from occurring, but will also help cut the rapidly rising heating bills of late.
Start by removing any old insulation. Next, seal any gaps in the attic floor with a spray foam. Next, add a layer of new insulation. In the Chicago area, the recommended R-value for attic insulation from the U.S. Department of Energy is 38–about a foot of insulation.
Homeowners also need to address roofing ventilation. A soffit-to-ridge ventilation system that runs continuously along the length of the house is recommended. That will permit cold air to constantly run along the underside of the roof, stopping any warm air from building up in the attic peak. According to industry standards, there should be one square foot of free ventilation for every 150 square feet of attic space.
Here’s another way to stop ice dams: You can install a rubber ice and water shield when the home is built or when a new roof is installed. The membrane will allow snow and ice to back up on the roof but not enter into the house. If ice dams are an annual problem with your home, you can also remove the lower few feet of roofing shingles, add the membrane and replace the shingles.
Another suggestion is to line the eaves, valleys, gutters and downspouts with electrical heating tape. The wires generate warmth that keeps melted snow from freezing up again. For this job, you’ll need to contact an electrical contractor versus a roofing contractor. Expect to pay about $2,000 for the job.
