You’ve probably seen the stories all over the news recently about roofs of school buildings, shopping centers, and homes throughout Massachusetts collapsing under the tremendous weight of all that snow. It certainly makes for some dramatic video news footage, but I’d like to talk about the less dramatic way that snow can damage your roof, ceilings, and walls by formation of ice dams. There are a number of reasons why ice dams form on the roofs of buildings. The most common way is from heat loss through the attic which causes the snow to melt, and when this occurs during periods of sub-freezing temperatures a ridge of ice slowly builds up along the edge.

Problems happen when water (from additional melting snow) becomes trapped behind this ridge and begins to back up underneath the shingles. As this water migrates inside the home, you will probably start to notice wet spots on the ceiling. You might also discover soaked flooring from water that has seeped down through the walls. (I experienced this firsthand several years ago during a heavy snow winter in the multi-unit building where I was living.) Aside from these obvious signs of water damage, (staining on drywall) other less noticeable damage is occurring to the home which can cause more serious problems later on if not addressed properly. Since these areas can take months to dry out on their own, water soaked insulation in attics and walls will support the growth of mold and mildew, and the wood framing may begin to decay. This type of situation is ideal for supporting an infestation of carpenter ants. Within a home, carpenter ants prefer to nest in areas with high humidity. In this case, the wet insulation will provide this need quite nicely. Also, the ants may further damage any framing that has begun to rot as they excavate galleries to raise brood and expand the colony.