One of the most common problems with homes in northeast Ohio is ice damming. During a typical cold snowy northeast Ohio winter you can commonly see homes with huge icicles hanging from the bottom edge roof line and a heavy buildup of ice on the edge of the roof just outside of the heated wall area below. This condition is caused by a combination of the cold weather and excess heat escaping from the home up through the roof due to a lack of adequate insulation.
As the heat moves up from the living area and through the attic it warms the roof and melts snow which then runs down the roof as water. When this snow water gets to the roof overhang (which is outside of the the heated area of the home and thus away from the effects of the heat) it begins to freeze. The level of temperature and whether or not the area is exposed to the sun determines how far the water runs before it freezes. On warmer days the snow water may run to the edge and then freeze somewhere as it descends along an icicle, and on cold nights the water freezes on the roof immediately after it passes beyond the heated wall area below. This condition does not occur on the roofs of unheated buildings.
The worst of the problems start once the weather warms up and the ice dam begins to melt. Often the ice dam holds back melted water on the roof for a prolonged amount of time allowing the water to find its way through any weakness in the roof system such as nail holes, worn out shingles, or damage caused by impact from falling branches or hail.
Once the water gets under the roofing layer it can travel into the walls, windows, rafters, insulation and even the electrical system. Water in the wrong places within a home causes rot and decay which leads to mold. It can also cause more substantial damage by flowing back into unheated sections of the home and then refreezing and expanding which can cause structural damage.
If an attic area is properly insulated and vented then ice damming should occur very little or not at all. Snow should lay on the roof until melted by the sun or warmer weather and not by expensive precious heat escaping from the house. The North American Insulation Manufacturers Association recommends insulation levels of R38 to R60 for attics in northeast Ohio. R value is a measure of heat retention.