Cold winter storms can wreak havoc on your roof. Ice can form on the eaves and can lead to leaks, snow can melt and slide off the roof like a mini-avalanche and carry roofing material and gutter with it. You can prevent most problems of these problems by keeping the attic cold, with efficient air sealing of the attic floor and well-placed vents to draw out any heat that dose escape from the house.
Ice Dams: These dangerous dams form at the eaves and can cause water form melting snow to back up under the shingles and leak into your home. Ice dams can result form alternate thawing and freezing of snow on the roof due to periods of warm days and cold nights. Or from heat loss through the roof of a poorly insulated and badly ventilated house, causing the snow to melt and then in cold weather to freeze again at the colder eave area.
Air Sealing: Your best defense against ice dams on your roof is to seal off all the places where warm air can leak into the attic from the house. To determine whether moisture problems are generated by interior or exterior sources, check the attic during or just after a storm. If there are no water leaks then check around all light fixtures that penetrate the attic floor and around ducts, plumbing stacks, and attic hatches. If light comes through any joints or you feel a draft, use caulking or weather-stripping to seal the space and create a solid air barrier to the attic floor.
Soffit Vents: These are your second line of defense against attic moisture and work most efficiently when all air leakage problems have been corrected. To prevent ice dams resulting from poor ventilation, install soffit vents and gable vents. When used together, they vent out warm attic air that might melt snow on the roof and cause ice dams. Electric exhaust fans actually pull warm air from the house and can cause damage and should be avoided.
Insulation: More insulation means a colder, less moist attic. Make sure that your insulation is distributed evenly and that there is full coverage of insulation through out the attic. If any of the insulation is damp, find the leak responsible and repair, then replace the insulation. Insulation should never touch the roof or block vents.
Eave Reinforcement: For extra protection on a sections of the roof where ice dams often form, you can reinforce the eave area by installing a sheet of roll roofing or rubberlike membrane under the shingles. This extends 2 inches inside the wall line.
Snow Buildup: Snow tends to slide off roof like an avalanche, tearing gutters off, ripping away roofing materials, and smashing plants below. Below are two suggestions for handling a snow buildup problem on your roof.
De-Icing Tapes: Electrically heated cables installed along roof eaves and in gutters and downspouts, allow for proper drainage of melting snow and ice, and help to prevent ice dams.
These tapes are attached to shingles in a zigzag pattern and are plugged into a waterproof electrical outlet. Once hated, they create drainage channels for water that otherwise would back up behind an ice dam or freeze inside the gutters and downspouts.
Snow Guards: To help hold snow in place, attach a metal snow guard in staggered rows along the roof. Snow guards come in many lengths including narrow ones for use over doorways.
