What Types of Roofs Are More Prone to Ice Dams?
If you're curious which roofs are more vulnerable to ice dams, in a nutshell, it's flat pitched roofs, particularly those with shingles. Shingles form various small layers, providing ice and snow with endless small toeholds to dig into. Shingled roofs, unlike slippery metal roofs, are full of little ridges. These ridges, as well as the coarseness of asphalt shingles, can hold ice and snow in place easily. You can equate it with rock climbers and how they require those little cracks or knobs to grab onto.
Metal roofs, on the other hand, aren't as susceptible to ice dams. Neither are steeply-pitched roofs. While metal roofs fend off ice dams fairly well, steeply pitched metal roofs are superior to warding off ice dams. There isn't anything for ice dams to stick to on metal roofs.
Common Causes of Ice Dams
Ice dams can cause a lot of damage to roofs. Ice dams are ice ridges that form on the edges of roofs and keep snow melt from being able to drain into the gutters. There are various causes of ice dams, including:
- Flat-Pitched Roofs
As mentioned, roofs that have a flatter pitch are more susceptible to ice dams since the water can't run off as fast as it would with steeper pitch roofs. This will increase the risk of water becoming stuck close to the roof's edge and refreezing into ice dams.
- Inadequate Insulation
Without adequate insulation, it enables too much warm indoor air to escape into your attic area. The warm air then warms up your roof enough to raise the shingle's surface temperature, melting the snow on the rooftop.
- Attic Too Hot
When you heat your attic improperly, it could result in many problems with water and ice buildup on your roof. A lot of individuals think it's better to keep their attics warm during the wintertime, but actually, the best thing to do is to keep them as close to the outdoor temperature as you can. As you've just learned, a warm attic can melt the snow on the roof and cause water to run down, refreeze and turn into ice dams.
One thing you can do is increase your attic ventilation by installing and using an attic fan. This will help keep the temperature of your attic as close to the outdoor temperature as possible which will help prevent the formation of ice dams. Attic fans are extremely popular in colder regions since they help prevent ice damming from occurring in the cold winter months.