Lowering the Likelihood of Ice Dams

ICICLES & ICE DAMS

Once again the recipe for icicles and ice dams is:

1. COLD WEATHER
2. SNOW
3. HEAT LOSS

ALL THREE ITEMS ARE REQUIRED

If one is eliminated there is no ice dam

Cold weather & snow 
Let\’s face it you can\’t do anything about it, we are at mother nature\’s mercy.

Icicles are the first signs that all 3 items exist. A ice dams is a build up over time. The number of days below freezing and how much snow on your roof and the amount of heat loss will determine the severity of this problem.

The good news is you need all three to have this problem.

There are many ways to solve it.
1 Ventilation
2 Insulation and a vapor barrier
3 Identifying other sources of heat loss (hidden factor)

Balanced Ventilation   Balanced ventilation is achieved when intake and exhaust allow for same amount of airflow, because the natural forces of air pressure create a push-pull effect around your roof.   Without proper exhaust, hot air cannot escape. Without proper intake, air will only circulate across the top of the attic space, leaving stagnant air at the bottom of the attic.   Circulation is also restricted when there are vents on only one side of the attic, similar to the effect one would get if only opening windows on one side of a house on a breezy day. Why Ventilation Matters   Proper ventilation necessitates that fresh air is able to find its way in the attic space, while allowing stale air to get out.   This is accomplished through the placement of ventilation near the bottom of the attic space at the soffits or eaves (intake), and at the top peak(s), or ridge(s), of your attic space (exhaust).    This will permit the circulation of air, which will keep the attic space at a uniform temperature and humidity level, regardless of the season.   When the temperature outside is below freezing the moisture in the air falls to the ground.   The air entering the attic is dry. This dry air pulls  the moisture in your insulation out. Wet insulation allow heat to past through it.   In order for attic ventilation to work effectively, however, the ventilation system must have balanced intake and exhaust. Preventing Cold-Weather Condensation   Winter weather can also presents many challenges for attics. As temperatures plummet, the warm, moist air that rises from living spaces into an improperly ventilated attic will condense on cold surfaces.   Over time this moisture can build and cause the insulation to lose R value ,roof decking to buckle, swell, and rot, making it unable to hold nails securely and reduce its load capacity.   Condensation also creates optimal conditions for mold and mildew growth, which affects allergy sufferers and has a negative impact on indoor air quality.
Proper ventilation will lower the likelihood of ice dams, save you money on heating and cooling, extend the life of your roof.