Ice dams on your roof are the outdoor sign of an indoor problem. A damaging ice dam doesn’t form because your roof’s too cold. Actually, it’s the opposite: uneven heating of the roof triggers the sequence of events that forms a mound of ice near the gutters called an ice dam. Here’s how it happens:
- Warm air from the living spaces of your home leaks through cracks and gaps in the ceiling into the colder attic. Heat energy also radiates through the ceiling. This rising heat inside the attic warms the underside of the upper portion of the roof, melting snow on the outside. Meanwhile, the lower part of the roof remains cold and frozen.
- As runoff from melting snow at the warmer roof peak reaches the colder, lower portion of the roof near the gutters, it rapidly re-freezes. A mound of ice gradually forms at the freezing point and obstructs flow of water into the gutters.
- Accumulated water backing up on the roof penetrates the shingles and seeps between joints in the roof sheathing. This water leaks down into the attic and eventually drips through the ceiling into rooms below.
Leakage from ice dams deteriorates wooden roof sheathing and structural components inside the attic. It also saturates and ruins attic insulation, triggers mold growth and damages interior ceilings and possessions in rooms below.
The remedy for ice dams is to reduce uneven roof heating. Eliminate the sources of heat infiltrating the attic by taking these steps:
- Stop the flow of warm air infiltrating through the ceiling by sealing cracks in the ceiling and walls, gaps around recessed lights and openings around vent pipes that pass through the ceiling into the attic.
- Make sure that pull-down attic stairs or access hatch close fully and are adequately weatherstripped around the edges.
- Verify that the depth of attic insulation meets current Department of Energy recommendations to inhibit radiation of heat energy from the living spaces into the attic.
For more strategies to prevent damaging ice dams, contact the professionals at Mowery Heating, Cooling and Plumbing.
Our goal is to help educate our customers in Brownsburg, Indiana and surrounding areas about energy and home comfort issues (specific to HVAC systems).
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