What is an ice dam?

An ice dam is a ridge of ice that forms on the eaves during the winter. This ridge of ice can become so high that it forms a puddle on top of your roof. Even though there are good shingles on the roof, this puddle can get deep enough to back up over the top of a shingle. Remember each asphalt shingle is only 13 or 14 tall, and they do not seal together to form a sheet. Hence, when water puddles up deep enough itll leak into the home. What causes an ice dam? Many things. Basically, if there is insufficient insulation in your ceiling the roof stays warm enough to melt any snow that falls. This water drains down towards the edge of the roof. Since your roof extends over the edge of your house (to form the eave), you can understand that the edge of the roof is colder since there is no heated space below it. Therefore, as the water runs down the roof, it reaches the eave and freezes. Potential ice dam problems often start as a row of icicles. Slowly but surely, this repeated action forms ...

Like the name suggests, an ice dam is a dam made of ice along the edge of the roof line, and as most dams do, an ice dam prevents melting snow from finding its way to the gutters and downspouts. Instead, the snow melting into water finds the dam of ice and refreezes forming even more ice. Sometimes the water backs up behind the dam and will leak into the house and cause damage to walls, ceilings, insulation, and other areas. Figure 1 shows a cross section of a home with an ice dam. What causes different roof surface temperatures? Ice dams form at the edge of the roof; this is due to a heat source higher up toward the peak of the roof causing the snow cover to begin to melt. This heat source is most always due to a lack of properly insulated attic space. The next time you drive through your neighborhood, look at the homes that have a full roof of snow – more than likely, these homes are properly insulated and vented… When you spot a home that has “vertical stripes” of visible roof ( ...  more

An ice dam is a ridge of ice that forms at the lower edge of a roof and prevents water produced by melting snow from draining off the roof. The water that backs up behind the dam can leak into a building and cause damage to walls, ceilings, insulation and other areas. What Causes Ice Dams? Non-uniform roof surface temperatures lead to ice dams. Heat loss from a house, snow-covered roofs and outside temperature interact and lead to ice dam formation. For ice dams to form, there must be snow on the roof, and, at the same time, the upper portions of the roof's surface must be above 32 degrees F, while lower surfaces are below 32 degrees F. For a portion of the roof to be below 32 degrees F, outside temperatures must also be below 32 degrees F. (When we say temperatures above or below 32 degrees F, we are talking about average temperatures over sustained periods of time.) The snow on a roof surface that is above 32 degrees F will melt. As water flows down the roof, it reaches the portion ...  more

An ice dam is a wall of ice that collects on the edge of a roof and keeps melting snow from being able to drain. The water that is prevented from draining can enter the home and damage ceilings, walls, and insulation within the house. An ice dam forms after a snowfall occurs, even if only one to two (2.5 to 5.1 cm.) inches of snow accumulates on the roof. Eventually, heat from the attic warms the roof and melts the snow. The melted snow then runs down the top of the roof until it arrives at a colder section, such as the gutters. Soon, the snow re-freezes, ultimately causing an ice dam. The worst ice dams are usually caused by heavy snowfall and frigid temperatures. Icicles hanging from a home's gutters is a sign that an ice dam is forming on the roof. If the situation is not corrected, the home can suffer extensive damage. A professional should be contacted in order to remove ice dams since trying to eliminate them can cause serious personal injury and roof damage. The professional ...  more

• What are Ice Dams? Ice dams are the result of weather conditions that cause a build-up of ice on a roof. Roofing shingles are installed starting at the bottom of a roof slope. The shingles overlap each other as they go up a roof slope. Roofing shingles, on average, overlap each other 7 inches. The roof system is therefore designed to shed water that runs DOWN a roof slope. The build-up of ice on a roof slope prevents the water from above from running down, or off of, the roof. It creates a dam, an “Ice Dam”. The ice dam causes the running water from above to be pushed backwards up the roof slope underneath the shingles. Once the water has been pushed past the 7 inch overlap it is under the shingles, and leaks into the interior. • When do ice dams occur? Ice dams can occur anytime during the winter season. Certain weather conditions can be ideal for causing ice dams. A snow fall followed by melting temps during the day and freezing temps at night cause ice to form near the eve, or ...

Melting snow often refreezes on the roof's overhang where the surface is cooler, forming an ice dam. Ice dams block proper drainage into the gutter and can cause water to backup underneath roofing components triggering wood rot of decking and rafters. During heavy snow periods, an accumulation of snow, ice and water may clog downspouts and gutters, damaging them beyond repair or tearing them off the house. While there is no guarantee against ice dams forming, the following preventive measures will reduce your risk: Make sure your attic has adequate insulation and check that insulation does not cover your soffit vents. If you don't have soffit vents, consider adding them. Install sufficient ventilation to expel heat and moisture. Ridge vents combined with soffit vents will improve attic air flow and validate most manufacturer's shingle warranty requirements for ventilation.

A. When roofs are not adequately ventilated, they become warm. Snow melts near the ridgelines of warm roofs and the water runs down to the cooler edges of the roof and refreezes. The recurring process of snowmelt and refreeze leads to an ice dam. This dam allows water and ice to seep under the shingles, soak into the decking, and even into the house itself. Because the heat from the house melts the ice, serious leaks can occur even when the temperature is below freezing. To prevent ice dams, maintain proper ventilation in the attic to keep the roof cool. Ice and water shield, a rubber-like membrane should also be installed under the shingles at high-risk areas such as eave edges and valleys.  more

• An ice dam is an area on the roof that tends to build up with ice. Poor ventilation and constricted drainage areas are causes of ice dams. We can often eliminate ice dams through ventilation. Every ABLE ROOF is designed to eliminate any interior leakage as a result of ice dams.  more

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. The water that backs up behind the dam can leak into a home and cause damage to walls, ceilings, insulation, and other areas. Figure 1 shows a cross section of a home with an ice dam.  more

An ice dam is a ridge of ice that forms at the edge of a roof, cricket, or valley that prevents melting snow (water) from draining off the roof. The water that backs up behind the dam can leak into the home and cause damage to walls, ceilings, insulation, and other areas.  more