Ice Dam Dilemma.
March 2, 2009
As the cold of months of winter continue to assault New England homeowners, our thoughts turn to roof ice dams. If you’ve had one, chances are you don’t know what causes them or what the fixes are.
As accumulated roof snow melts and re-freezes, it forms a blockage at the edge near the gutter that prevents water from melting snow to drain off the roof and into gutters and down spouts.
If you’ve ever tangled with one, you know that remediation of an ice dam can be perplexing. They vary in severity, so a 'fix' can appear to work one year but fail the next.
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Cold got you down? Spring will be here soon, and the time to clean up from the ravages of winter. As winter lingers, keep an eye on your roof and gutters. If you find that snow piles up and freezes in a heap on the edge of your roof, you may be growing what we call ice dams. NOT a good thing.
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Part of the problem stems from a lack of understanding about what causes them. You can wind up treating symptoms rather than root causes- until the real dam-age is done.
A killer
Water trapped behind an ice dam is a wallboard killer. It seeps though the shingles of the roof, causing immediate damage to interior walls, ceilings and insulation. Longer term, the dampness can create a breeding ground for mold and mildew as well as contribute to structural damage. Over the course of the winter, as more roof snow accumulates, the cycle of melting and freezing continues, creating an ever larger ice dam and increasing the damn problem!
The good homeowner
A conscientious homeowner will annually clear clogged gutters, removing accumulated twigs and debris. Some enterprising souls install heated wires along the edge of the roof or use rakes to remove snow after a big snowfall. Warning! If you’re pulling snow or ice off the roof and depositing it next to the house, make sure you don’t let it build up against the foundation. Gutters and down spouts are designed to collect and channel water away from a house. Heavy amounts of snow piling up next to the foundation will melt and can seep down the side of the foundation and into your basement.
But we digress. The root cause of an ice dam is heat loss due to inadequate ceiling insulation. Poor attic ventilation, and wet or ineffective insulation in the walls or ceilings will make the condition worse. Heat escaping into the attic from the heated living areas of a home causes the roof to warm above the level of the outside air temperatures. Since heat rises, the peak of the roof is always warmer than the edge near the gutter. The snow on the peak of the roof melts and the water drains down to edge of the roof where it freezes, forming an ice dam. The severity of ice dams varies according to the amount of snow, the ambient outside temperature, and the amount of heat loss.
The only part of this equation you can control is the amount of heat loss.
Most homeowners believe that their ceilings are properly insulated (to prevent heat loss) and that their attic is properly vented (to remove any minor or residual heat loss). Insulation may meet minimum standards, (R-values), but may not be sufficient to prevent ice dams or could have been installed poorly. It might have gotten dislodged overtime during minor repairs or remodeling.
One homeowner suffering from ice dams discovered that a pest service had pushed aside insulation searching for carpenter ants and failed to replace the insulation, causing substantial heat loss. Another homeowner learned that a sun lamp and ceiling vent in the guest bathroom weren't properly insulated-but only much later when his teenage daughters began spending the relentless bathroom hours necessary for their beautification and generated volumes of heat in the attic that triggered ice dams.
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| Before - Open insulation and unprotected piping. Minimally insulated ducts are conduits for cold air when the heat isn’t running. |
In progress - Taped plywood flooring, a hinged fan box designed to open when the fan turns on, boxed and taped ductwork. |
After - Your attic sealed: A heart-warming sight. |
Here's a simple three-step plan for eliminating ice dams:
1. Evaluate air leakage into your attic. Whole house fans and pull down attic stairs, heating system ducts and loosely laid insulation conspire to create an escape route that sends your hard-earned heat through the roof. Sealing off those places can dramatically improve heat conservation and diminish the conditions that lead to ice dams. Modern building science recommends insulating rafters to combat air leakage. Please consult us before doing this, as it’s a pricey fix, and mistakes can be costly. (Good news. If you do it, you can eliminate step #2 below.)
2. Make sure your attic is properly vented. An annual inspection will ensure that the ventilation is adequate and that all necessary vents are unobstructed.
3. The residual damage from old problems will compound overtime leading to ever more costly repairs that can be avoided. If you've suffered from ice dams before, make sure that all damaged areas have been repaired. Remove and replace all wall and ceiling insulation that may be damp, compacted or dislodged.
Spring is coming! Never attempt to climb onto your roof in the winter. If you suspect heat loss and/or see, some of the telltale effects of ice dams, do some careful inside inspection, document your findings, and wait until the sustained cold starts to subside. Give us a call at 860-355-0906. We’ll help you assess what your needs are and how best to meet them.
Mason Lord, President
Hudson Valley Preservation
And, remember, the greenest building is the one that’s already built. Next time, you’re in the market for more efficient living, call Hudson Valley Preservation -we’ll help you grow space you never thought you had!
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