The sight of glittering icicles dangling from the edge of your home's roof can be picturesque. But don't let the beauty fool you. Icicles are a sign of "ice dams," which are signs of trouble for your roof that can lead to expensive damage to your home.
Ice dams are formed when the roof warms up under a blanket of snow or ice. The warm roof melts the snow and the resulting water runs down toward the roof edge. When it reaches the edge of the roof the snowmelt is again exposed to cold air and can refreeze. This is especially prevalent if the gutters are clogged with debris and backed up. That is when those pretty icicles start to form and grow!
The problem is that the ice dam backs up the flow of water and forces it under the roof edge and into the home. The water then may travel along rafters and walls and seep into ceilings, wall panels and, eventually, the home's foundation. This may cause rot, mold and structural damage that can cost thousands of dollars to repair.
There are steps you can take to prevent ice dams from forming. One is to make sure your home's gutters are kept clean and clear of debris. A "gutter shutter" protective system is a great way to keep leaves, pine needles and other debris out of your gutters while still allowing rainwater runoff to flow.
Believe it or not, the most effective ice dam prevention method is to cool down your roof. The roof deck heats up primarily from below, when warm air from your home rises into the attic space and raises the temperature of the roof.
The first step to take to keep ice dams from occurring is to make sure your roof is properly ventilated. A properly vented roof keeps attic temperatures consistent and helps prevent the formation of ice dams. The best ventilation is with a full-length ridge vent that allows air to flow freely under the entire length of the roof deck. This helps to maintain a good balance between the outside temperature and the temperature in the attic space.
Another way to prevent temperature imbalance is to insulate your attic. But do not add insulation to the underside of the roof deck itself. Instead, insulate the floor of the attic or the ceiling of any upper story rooms in your home. That allows cooler air to remain close to the roof deck.
Your best bet is to contact a qualified home services contractor to examine your roof and determine if the potential for damaging ice dams is present.