In light of heavy snow and stories of collapsing roofs, the concerns regarding snow load have really hit home. So what is snow load and what can a homeowner do about it? According to AccuWeather, a cubic foot of dry snow weights about 6 to 8 pounds, while one cubic foot of packed snow could weigh up to 20 pounds. The same volume of ice can weigh three times this amount. Roofs are engineered to handle a certain amount of weight based on their pitch (inches the roof rises vertically for every 12 inches it extends horizontally). The steeper the pitch, the less likely snow will accumulate on the roof. Homes with low pitch or flat roofs are at increased risk to accumulate snow and collapse under the snow's weight. The average residential roof is engineered to handle 25 pounds per square foot - which is typically about 20 inches of snow. Older homes, built before building codes were incorporated may not meet this minimum standard. When we have rainfall on top of snow, a lot of weight can be added to a roof quickly.
There are several indicators that a roof may be on the verge of collapse: sagging roof, severe roof leak, cracked or split wood members, bends or ripples in supports, cracks in walls or masonry, sheared off screws from steel frames, indoor sprinkler heads that that have dropped down below ceiling tiles, doors that pop open, doors or windows that are difficult to open, bowed utility pies or conduit attached at ceiling, creaking or popping sounds.
Homeowners should consider having excess snow removed from their roofs. There are licensed professionals who do this - a roofing contractor or arborist may be a good choice. Snow rakes can also help, but be careful with this as snow rakes can push a lot of snow and icicles off a roof onto people, pets, and plants below and it is dangerous climbing on a roof at anytime, much less with ice and snow. Those who want to do it themselves should use extreme caution and may want to consider hiring a professional.
Original post can be seen at Bend Premier Real Estate's blog.