Preventing Ice Dam Issues This Winter
Icicles are beautifully captivating during the snowy New England winters. They hang like glittering diamonds from tree branches and rooftops making lights and reflections sparkle. Unfortunately, the mesmerizing beauty of these icicles can be damaging and dangerous when they are attached to gutters, eaves, and rooftop edges of homes and businesses.
While icicles can create a quaint winter wonderland scene on the exterior of your home, the heavy frozen chunks of ice can tug at gutters, damage roofing shingles, and cause interior leaks. It will make you think twice about their supposed beauty because beneath those icicles may lay ice dams that could spell disaster.
What Are Ice Dams?
An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow (water) from draining off the roof.
These dams form when attic air becomes warm enough to heat the underside of the roof, which in turn causes the snow on top of the roof to thaw. The melting snow runs down the roof until it hits snow that is below freezing.
At that point, the snow refreezes and creates a growing ridge of ice. The block of ice, now considered an ice dam, blocks more melting snow from running off the roof. The cycle continues until the dam melts or remediation techniques are used to solve the problem. This illustration from This Old House shows a cross-section of a roof and how an ice dam can develop:
Impacts of Ice Dams
One of the most visible and potentially costly impacts of ice dams along the eaves of your home can come in the form of water damage. The water that backs up behind the dam can leak into a home and cause damage to walls, ceilings, insulation, and the attic. Additionally, the water that can find its way into your home can warp floors, cause mold build-up, and create situations where ceilings are stained or (worse yet) sagging from the water damage.
On the outside of the home, ice dams can rip off gutters as the ice expands and grows in size and weight. They can also damage shingles and soffits, as well as deteriorate the paint on the exterior of your home.
If ignored, ice dams can lead to the growth of mold and mildew inside the home, especially within the attic insulation, and potentially cause respiratory problems for residents. Air quality can suffer greatly with unabated ice dams every winter.
Immediate and Long-Term Ice Dam Prevention
There are a few steps to resolve this problem in conjunction with one another. One method to prevent ice dams from forming on the edge of your roof is to control the heat loss from your home - especially through the attic and roof area.
Long-term action can be taken to seal your ceiling and make sure that all the heat from your home does not escape into your attic. This can be done by checking the attic insulation and ensuring that the attic floor is stopping the flow of warm air rising. Weather stripping and sealing any attic hatch can also stop the warm air flow from making it into the attic and warming the roof. Remember the ultimate idea is to stop the snow from melting and piling up on the cooler edges of the roof.
Another method of controlling heat loss in a home is through the ventilation system. The ridges and soffits are meant to keep the cold air moving under the roof. A professional inspection of these components can determine if the airflow is adequate to prevent the growth of ice dams.
Short-term solutions for homes that are experiencing ice dams could include having a professional properly use a long-handled aluminum roof rake to remove excess snow off the surface. Another immediate solution could be blowing cool air into the attic to freeze the ice dam within minutes. From there, professionals will want to take other steps to make channels in the ice dams and allow water to flow off the roof.
We have found that homes insulated properly with spray foam insulation have a greatly reduced risk of ice dams forming. This method of insulation also negates the need for attic ventilation. Not all homes are good candidates for spray foam insulation, however. Working With a knowledgeable professional will be critical to creating or improving the correct system for your house to mitigate the threat of ice dams.