When snow melts and runs down the roof it often refreezes at it reaches the edge of the roof and the gutter.
Ice melting roof leak.
The cold air helps freeze the melting ice back up.
An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow water from draining off the roof.
For this discussion an ice dam is a place where you have melted snow that freezes on the roof which eventually builds up and blocks the downward flow of other melting snow.
The water that backs up behind the dam can leak into a home and cause damage to walls ceilings insulation and other areas.
As even more water runs down it now has nowhere to go so it backs up under the shingles and leaks into your roof.
Not gutters or the lack thereof not frozen gutters not low pitched roofs.
The water trickles down between the layer of snow and the shingles until it reaches the eave of the roof which stays cold because it extends beyond the side of the house.
There is a single cause for ice dams and the subsequent leaks.
Sometimes this backed up water can travel as much as 5 10 feet under the shingles.
This type of leak is not workmanship related and is not covered under labour warranties.
Note where the leaks are so you can look for them after the weather warms up.
They will often be behind ice dams on the roof.
As more snow melts more water runs down the roof and meets the ice build up or dam and backs up under the shingles and into the attic.
This backs the water up under your shingles allowing it to run down the exterior sheathing or interior walls and ceilings sometimes for great perplexing distances.
Moisture entering the home from ice dams can lead to the growth of mold and mildew.
Dripping water or water stains make them recognizable.
When your roof heats up and melts the bottom layer of snow or ice the water leaks down to the edge of your roof and freezes again creating an ice dam.
The melting snow is often caused by warm moist air escaping into the attic due to a poor vapour barrier.
An ice dam forms when the roof over the attic gets warm enough to melt the underside of the layer of snow on the roof.
Effects of ice dams.
Fill pantyhose with sidewalk salt to break up ice at the edge of the roof.
Providing a drainage path for such water accumulations is one way to stop ice dam leaks dead in their tracks.