Don’t just look down when you are outside in Alberta during cold and warming weather trends. As a homeowner – you need to also be looking up!
ICE DAM FORMATION
An ice dam is the ridge of ice that forms at the edge of a roof which prevents melting snow from draining as it should. The water that backs up behind the ice dam can leak into the home and cause damage to walls, floors, ceilings, insulation, and other areas.
Ice dams (and icicles) form when snow melts, runs down your roof and refreezes near the edge. This only occurs when part of your roof warms to above 32 degrees F, warm enough to melt the snow, while the roof edge remains below freezing. Melting snow can form an ice build-up in the eavestroughs which can contribute to ice dam formation.
Ice damming is caused by the continual melting and refreezing of the snow on your roof. Ice dams on the roof cause water to back up underneath the shingles or fascia boards, leading to potential damage to the roof deck and even ceilings and walls in your home.
ATTIC FROST 2016/2017
The combination of higher outside humidity and the extreme temperature swings that have been occurring can cause frost to form in many central Alberta attics. This frost in attics and on or in roof & exhaust vents during drops in temperature will melt as the temperatures rise. This can result in water dripping from vents, plumbing stacks and exhaust fans.
The small amount of air leakage around the attic hatch can also result in frost formation around the opening, which can then melt and drip back into the home. Frost will also form on any nails and may cause dripping sounds as well when melting.
Degree of frost accumulation is related to relative humidity of air, rate of air movement & length of cold spell.
Relative humidity is the amount of moisture in the air compared to what the air can “hold” at that temperature. Air can hold only a limited amount of water vapor and that amount depends on the air temperature. When the air can’t “hold” all the moisture, it condenses and forms frost or ice. Cooler air cannot hold as much water vapor as warmer air.
When temperatures rise this quickly, the frost buildup may melt faster than the attic air circulation will be able to exhaust the accumulated moisture. The normal air circulation in the attic will eventually remove the accumulated moisture in the attic.
It is recommended that an annual inspection of the attic be performed by the homeowner to ensure that insulation has not been displaced by wind or blocking soffit insulation stops and that any exhaust tubing is still attached and venting correctly. As a homeowner you have a responsibility to mitigate possible damage by maintaining correct humidity levels and wiping up visible water in your home from frost melting on windows, doors etc. to prevent things like peeling trim paint.