What You Need to Know About “Ice Dams.”

Philadelphia’s weather can get cold and wet during the winter months. Snow and ice on your roof can pose several problems. But the most dangerous is the formation of “ice dams.”

An ice dam forms when your roof deck warms and the snow covering your roof melts from the bottom up. The melted snow runs down to the edge of your roof where it is once again exposed to frigid air and refreezes, either on the roof edge or in a clogged gutter. This forms the ice dam.

Now the additional snowmelt that runs down your roof has no place to go except to be forced back up and under your roof shingles and into your home. Once water gets into your home it can travel anywhere – along the rafters, across ceilings, down walls and even into the basement. The damage can be significant and expensive, including rotted wood, mold, mildew, stains and cracked foundations.

The problem that causes ice dams is not actually the roof, but the attic. If your attic is too warm it heats up the roof deck and causes the snow to melt. The secret to preventing this is to lower the temperature in your attic to match that of the roof.

There are two ways to do this, and we recommend using both of them. The first is to install a balanced ventilation system that provides intake air and exhaust.  This provides a path for cool, dry air to enter the attic (usually near the floor of the attic) and the warm, moist air to exit near the peak.

The second step is to install adequate insulation on the floor of your attic. Standard insulation should not be directly attached to the underside of the roof deck. The proper amount of insulation will keep warm air from your home from rising up into the attic and heating the roof deck, thus causing snow on the roof to melt.

The time to take these steps is before the snow falls. Ice dams can form without you even knowing it and may not become obvious until the damage is done.

That snow on your roof should stay up there a long time and melt very slowly because, with proper ventilation and insulation, your roof deck is now cold.

Free Inspection

Free Estimate