In the winter, icicles can form on the eaves of your home. Ideally, you don't want icicles to form on the eaves of your home during the winter time. Here are the three primary reasons icicles may form on your roof during the winter.
#1 Melting & Freezing Cycle
First, you may get icicles on the edge of your roof simply because of the freezing and thawing cycle. Snow on your roof may melt and slowly drop down your roof. Snow is more likely to melt on the top of your home where heat is escaping from your attic and from your home. As the snow turns to water and melts down your roof, it may re-freeze again as it gets to the edge of your roof, where there is not as much heat being let off from your roof and the water is going to come into contact with the outside air and may freeze again.
The water may also freeze as the temperatures change outside and cools down as night approaches again. This is just part of the melting and freezing cycle that happens with snow on your roof during the winter time.
One way to break this freezing and melting cycle is by installing a heated layer around the outside of your roof to heat things up making the edge of your roof warmer and keep the eaves clear of icicles.
#2 Poor Ventilation
Another reason why you may get icicles that form on your roof is because of poor ventilation. This is caused by warm air coming off of your roof coming into contact with the colder outside air in the winter time. This can lead to condensation gathering on the underside of your roof deck. This condensation tends to flow downward and gather on the eaves of your home, where it can then cause icicles to form.
This type of icicles formation can be prevented by making sure that you have good air flow intake vents installed near the eaves of your home as well as good exhaust vents installed near the top of your roof to make sure that the air moves correctly and in a way that prevents the formation of icicles.
#3 Dryer Vent
Next, if you have a dryer vent that exits out through the attic instead of out of the side of your home, this can generate a lot of heat on a specific area of your roof. Other vents from appliances such as gas water heaters can also generate a lot of heat in one specific area, resulting in snow that melts and then re-freezes very quickly as it moves away from the heat source and encounters the outside air. This can be counter-acted by redirecting these vents so that they do not come out of the top of your roof but out of the sides of your home. This can ensure that icicles do not form on the top of your home because of these types of issues.
You can also have a roofing professional, such as one from Click Lock Roofing, come out and inspect your roof and determine what you can do to prevent icicles from forming on your roof.