Icicles are an iconic symbol of winter. Reproduced in crystal, plastic, and lights as decorations on trees and houses. They are both beautiful and dangerous at the same time. Falling icicles have been used to take out the bad guy in books and film. Ralphie blamed an icicle falling from the roof for breaking his glasses in A Christmas Story when we all know he almost shot his eye out.
In reality icicles hanging from a gutter may be a sign of a much bigger problem especially during times of the daily temperature being around freezing. Inadequate insulation and poor airflow can cause escaping heat to collect in the attic which can melt the underlying snow closest to the top of the roof. The water runs down until it reaches the unprotected eaves and gutters where it refreezes before it can go down the spout. When enough ice accumulates it can actually prevent subsequent water from reaching the cooler section and refreezing. This water can then back up under shingles and start working its way into the house. You can click the diagram for a larger version.
What is an ice dam?
An ice dam is a ridge of solid ice that forms at the edge of the roof caused by melting snow that runs down a warm roof surface and freezes when it reaches the cold roof eave edge.
Continually melting roof snow causes water to pool behind the dam. The water works its way under the roof shingles and into the house—running down walls, along ceilings and across floors. A roof full of snow could result in hundreds of gallons of water coming into the house.
Preventing ice dams
If the underside of a roof, typically the attic space, remains nearly as cold as outside, little to no unwanted roof snow melting will occur. To keep a “cold roof,” consider the following:
• Add insulation. More insulation on the attic floor keeps the heat where it belongs and out of the attic.
• Install ridge and soffit vents. A ridge vent paired with continuous soffit vents circulates cold air under the entire roof.
• Cap your attic hatch. An unsealed attic hatch or whole-house fan is a large opening for heat to escape. Enclose these with foil-faced foam board insulation and aluminum tape.
• Install sealed recessed lights. Older recessed lights give off excessive heat and cannot be insulated without creating a fire hazard. Replace them with sealed insulation contact (IC) rated fixtures, which can be covered with insulation.
• Seal and insulate ductwork. Seal joints of HVAC ducts and exhaust ducts and wrap with foil faced insulation to prevent heat from escaping.
• Consider an energy assessment. An assessment can pinpoint exactly where you are losing heat in the home. It can save you money and possibly prevent ice damming damages.
Article courtesy of Big I Markets