Ice dams–What are they?
An ice dam is a wall of ice that forms at the perimeter of your roof after a large snow fall, followed by freezing temperatures. If you notice icicles forming at the edge of your roof, or a heavy build up of ice in your eaves troughs and gutters you have an ice dam. Ice Dams can cause significant damage to your roof system, interior walls, insulation, and the structural integrity of your home, so prevention is important.
Ice dams are formed when two conditions meet: heavy snowfall and improper attic ventilation and insulation. Snow builds up on your roof, and outside temperatures fall below freezing. Simultaneously, warmer attic air rises, causing the snow to melt. The snow melting turns into a river of water and begins to flow down the roof slope. Water travelling down, refreezes when it gets to the colder part at the roof edge. This refreezing will form a wall of ice trapping or creating a dam for more water as it flows down.
The problem gets worse as the back log of slush and snow created by the damming forces the shingles up dislodging nails in the process. Nail holes and small cracks are perfect pathways for flowing water. Water pathways make their way into your attic, seeping through your insulation and migrating into your walls, and through your ceiling. The end result is damage to the interior of your home and personal property. These are the obvious effects of leaking as a result of an ice dam. If the leak is not obvious it may be years before you notice mold or wood rot.
Having 6 inches or more of ice on your roof, means you must lighten the load to avoid structural damage. This is not A Do it yourself project. Using ice picks or chain saws is a perfect way to ruin your roof system, and invalidate your shingle warranty. Please call a professional.