Snow starts to melt in certain areas of the roof which are warmer than others due to heat loss from the attic.
Ice dam roof vent.
Ask this old house general contractor tom silva explains the best ways to keep your roof and gutters free from those dreaded ice dams.
An ice dam is a solid ridge of ice that forms along the edges of your roof.
Ice dams may seem harmless at first but they are known to cause thousands of dollars in roof leaks structural damages and repairs of your home.
Lay the hose onto the roof so it crosses the ice dam and overhangs the gutter.
When the water reaches the colder edges at the bottom of the roof it refreezes forming a wall of ice.
As water flows down the roof it reaches the portion of the roof that is below 32f and freezes.
The melted snow turns into water that starts running down the roof surface underneath the snow pack.
An ice dam is a mass of ice that gathers along the lower edge of rooflines.
They occur in climates with cold winter temperatures and regular snowfall.
See below for a shopp.
This causes the ice dam.
Ice dams prevention ventilation of low slope roofs.
The dam grows as it is fed by the melting snow above it but it will limit itself to the portions of the roof that average below 32f.
Ice dams and icicles form when the snow melts runs down your roof and refreezes near the edge.
The last thing any homeowner needs during winter is a collapsed leaking or unsafe roof.
Ice dams are a sign of heat loss in the attic and this lost heat is money you throw out the window.
Fill the leg of discarded pair of panty hose with a calcium chloride ice melter.
Ice belt metal panels many roofs are made of shingles which work well to remove water until it starts to travel upward.
So the water above backs up behind the ice dam and remains a liquid.
Severe ice dams can weigh many hundreds of pounds compromising the structure of the roof eaves.
To take a more pro active approach in preventing ice dams you can install ice belt metal panels which are installed along the eaves to block water.
More critically ice dams can cause meltwater to back up under the shingles where it can flow down and ruin ceiling and wall surfaces.
This only occurs when part of your roof warms to above 32 degrees f warm enough to melt the snow while the roof edge remains below freezing.
If necessary use a long handled garden rake or hoe to push it into position.
Any roof anytime snow and ice that melts and then freezes again can cause ice dams heavy snow build up and icicles to form resulting in structural damage and safety concerns.
Ice dams can cause very serious and expensive to fix problems and are usually caused by improper ventilation of your attic space and inadequate insulation of your roof.