Curling Roof Shingles A Result Of Poor Ventilation - April 1st 2015
Q: I have recently noticed that the edges of our roof shingles have started curling at the edges just above the gutters. What is causing this and do we need to do something to stop it?
A: Curling shingles are caused by inadequate ventilation. In some cases, this may show up after you have added to your insulation. When new insulation is added or blown into the roof cavity, the venting through the soffits can be blocked if insulation stops are not installed.
These insulation stops allow air to vent up around the insulation and roof sheathing. If the vents are blocked, warm moist air can escape out around the sheathing boards and freeze, forming ice dams under the shingle flaps and cause them to curl. When the ice melts, the shingle will remain curled, causing deterioration.
Therefore, it is important to make sure the vents are free of any insulation blockage when upgrading with additional insulation.