Ice dams occur when snow melts near the ridge lines of warm roofs (roofs without adequate ventilation). As the water runs down the roof to the overhang, it cools and freezes. If the snow continues this melt and freeze process, an ice dam can form that can seep under the shingles, through the decking and into the house. This, of course, can cause serious roof leaks--even in freezing temperatures. The best prevention to ice dams is a well-ventilated (cool) roof. Additional protection for your roof can be applied with an impermeable ice and water membrane. The membrane is installed on top of the decking, under the roofing material. Temporary prevention of ice dams can also be done through the use of electric cables along the eaves of the roof (where the dams usually form). However, new ice dams can form above the cables and still cause extensive damage. Another emergency solution to ice dams is to fill a sock or nylon with calcium chloride. Lay the stocking vertically across the ice dam. The calcium chloride will melt the ice and release the water so that it can drain outside, and not inside your roof.
A situation created by the accumulation of ice or snow on the roof, particularly at the eaves, where the ice or snow in contact with the roof surface melts, and the resulting water has no place to go, but through capillary action, be drawn back under the slates and into the attic, resulting in a temporary leak.
(1)The condition formed by the refreezing of melted water usually at the eaves and in gutters, which causes water to backup under roofing materials. (2) A self adhering rolled product applied to prevent this condition.
a buildup of ice and water caused by snow on rooftops
a build up of ice and water that works its way under shingles / shake s
a build up of ice at the edge of the roof
a buildup of ice that results from melting snow that freezes at the overhang
an accumulation of ice at the lower edge of a sloped roof, usually at the gutter
a ridge of ice developing at the edge of a roof
a ridge of ice that forms at the edge of the roof and prevents melting snow (water) from draining off the roof
a ridge of ice that forms on the edge of a roof and
a winter build-up of ice that occurs on the roof of buildings particularly those with gutters
Ice formed at the lower edge of a roof that is caused by the thawing and re-freezing on melted snow. An ice dam can force water under the shingles.
A building up of ice at the lower section of the roof causes by melting snow which refreezes at the cold overhang.
A condition which can occur with snow and freezing conditions. When snow or ice melts on a roof over a heated or partially heated attic space, the melting water may refreeze over an unheated areas such as a roof overhang. This re-frozen water may create a "dam" and allow additional melt water to back up under shingles and cause leaks (Illustration "A"). Solutions include: proper roof venting and insulation (Illustration "B"), membrane roofing or roofing underlayment, and heat tapes. Once an ice dam occurs, remedies are difficult and or dangerous. Working on a frozen roof should be avoided, as should the use of any open flames. The use of hot water to melt the ice may help, it may also increase the amount of leakage.
A buildup of ice, which forms a dam on the roof covering along the eave of the building.
Ice formed at the transition from a warm surface to a cold surface, such as along the overhang of a house. The build-up of ice is the result of ice or snow melting on the roof area over the warmer, living area of a building and then refreezing when it runs down and reaches the overhang.
A collection of melted snow that refreezes, typically at the projecting eave of a sloping roof. The ice dam causes the water from melting snow to back up under roof shingles.
When a snow load melts on a roof and re-freezes at the eave areas. Ice dams force water to "back-up" a roof and cause leakage.
Condition formed at the lower roof edge by the thawing and re-freezing of melted snow on the overhang. Can force water up and under shingles, causing leaks.
Condition caused by freezing and thawing of snow on the roof overhang that results in trapped water causing leakage.
An ice obstruction along the eaves of a roof caused by the refreezing of water emanating from melting snow on the roof surface above.
a mass of ice formed at the transition from a warm to a cold roof surface, frequently formed by refreezing melt-water at the overhang of a steep roof, causing ice and water to back up under roofing materials.
Frozen patches of snow along the eaves of a roof that cause melting snow to puddle and possibly leak through the roof.
