An ice dam is a hump of ice that forms at the edge of a roof under certain wintertime conditions.
Ice dam on roof valley.
Effects of ice dams.
The home of your dreams may have six glorious roof valleys so i don t want to speak ill of it but those valleys can create a few problems as far as ice dams are concerned.
What is an ice dam.
That s because the same conditions that allow icicles to form snow covered roofs and freezing weather also lead to ice dams.
Dams can tear off gutters loosen shingles and cause water to back up and pour into your house.
There s almost always more snow in roof valleys than anywhere else on a roof.
Thick ridges of solid ice that build up along the eaves.
Finally ice accumulates along the eaves forming a dam.
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.
An ice dam can damage both your roof and the inside of your home.
Or ice dams may consistently form at the foot of roof valleys the junction where two roofs meet at a right angle because they fill with windblown snow.
The rafter bays were not insulated adequately when the house was built and because the rafters in the valley terminate at the valley rafter those rafter bays are completely sealed and cannot be ventilated.
The water that backs up behind the dam can leak into a home and cause damage to walls ceilings insulation and other areas.
Ice dams are a common sight in northern new england winters and home partners has dealt with quite a few.
The most common areas of the home for ice dams to form are.
How to prevent ice dams use heated cables.
At the eaves of the roof by far the most common spot for ice dams heat cables also known as heat tape or roof ice cables are often the first things that come to mind for homeowners attempting to deal with.
In valleys of the roof.
That s when you have to call on secondary strategies and ice dam prevention products to prevent ice dam damage.
Around chimneys and skylights.
Now that you know how ice dams form here s a quick and easy way to prevent them.
Snow accumulates in valleys.
Attached with clips along the roof s edge in a zigzag pattern heated cables help prevent ice dams that lift shingles and cause leaks.
The minimum is typically 2 feet 24 inches or 0 60 m above the vertical projection of the inside of the exterior wall.
Meltwater from the warm roof backs up behind it flows under the shingles and into the house.
Ice and water protector must reach above the highest expected level of ice dams which will vary by region and the slope of your roof.
Ask this old house general contractor tom silva explains the best ways to keep your roof and gutters free from those dreaded ice dams.
It will put gutters and downspouts at risk too.
As a result heat escapes from the living space melting snow on the roof and creating an ice dam in the valley.
