Ice dams occur when ice melts and then refreezes before it runs off the roof. These ice dams can not only damage your home but set up your home for other issues.
How are they formed?
In the event of a light snow, the warm sun in the morning may quickly melt the ice and create a slow trickle of water down the rooftop. But if the weather suddenly turns cold, that trickling water can refreeze creating a dam of frozen ice on the edge of your roof or even on your lower shingles.
This can also happen when heat leaving the house at the top of the roof melts the snow but it refreezes when it gets toward the roof’s lower edge where it is colder. If the loss of heat is extreme this can really cause a big issue putting presure on the edges of the roof.
Ice Dams can cause roof leaks.. This can create both long term and short term problems.
Short term problems include wet insulation.
Long term problems can include the compression of the materials in your attic, water spots, mold and over all higher heating bills.
Not only that, but water will often leak down within the wall frame, wetting wall insulation and causing it to sag, leaving uninsulated voids at the top of the wall. Not only does this again rob energy dollars, but it will also trap moisture within the wall cavity between the exterior plywood and your interior vapor barrier. This results in smelly, rotting wall cavities, structural framing members can decay, metal fasteners can corrode, mold and mildew can form on wall surfaces due to elevated humidity.
Ice dams are a preventable condition. To start to mitigate problems, you should check the insulation of your home for lost heat. Once you know where those areas are, repair them quickly. Then make sure you check each year for new occurances. Due dillegence will help prevent this issue from happening and limit the damage to your home.