Most roofing materials are designed to work under the influence of gravity.
Water leaking from snow on roof.
Heat leaking up from your home is melting the snowpack in the tight roof canyon.
The melted water flows under the snow and freezes as it reaches the unheated soffit area at the eaves thus creating an ice dam.
Ice dams also can cause leaks as water backs up under the shingles on the portion of the roof that sits over the soffit.
While in the attic if water is not visible on any wood look for water running down pipes that penetrate the roof and also look for water around the chimney.
The backup of melted snow on the edge of your roof which can refreeze into ice is called an ice dam.
And on occasion a hard driving rain with whipping wind will cause roof vents to leak water.
This roof leaks during the snowy part of winter and during storms in the summer certainly due to poor flashing.
After the rain has stopped and it s sunny outside examine the exterior of your roof to look for problem areas that may be causing the leak.
If your roof vent leaks during heavy rain the rain may be blowing up under the hood and into the vent.
An ice dam occurs when snow melts and the water freezes when it hits the colder edges of your roof.
Snow builds up on the roof and tends to melt from the bottom up but a cold snap freezes the water making the dam.
In our experience it is unusual to get roof leaks cause by ice dams when no appreciable ice accumulations can be seen from the ground.
When the roof was snow and ice covered that part of the roof would melt faster causing water to pond which was then wicked up by the dormer structure.
It is common to see water ice coming through the soffit or down the exterior wall when ice dams have developed to the point where they are forcing water to back up into the roofing system.
In the case of heavy snow and ice during the last bad winter that s even more ponding water than usual.
In the photo you can still see signs of an ice dam.
When that blocked water from melted snow or ice cannot escape off of the roof it can accumulate and can back up to a depth that causes the water to find an opening to leak into the building.
The soffit that meets the roof is one of the toughest areas to waterproof.
Mark any problem areas with chalk.
This was the cause of the long standing interior moisture issues.
It can happen however.
What happens is this.
If your house has icicles hanging off the edge of the roof this can be an indication of an ice dam formation on the roof.
The cold weather turns the super chilled water to ice and the ice pack begins to get thicker and thicker creating a dam quite like hoover dam but a much smaller.
Then more snow melts above the dam but is stopped by the.
