How Much Does Snow Weigh on your Roof?
With all the news of roofs collapsing Along the East Coast, here is something to help you understand if you should worry about your house or not.
Here is an Information Graphic Designed to help you understand just how much snow your roof can hold, assuming its a typically built roof following minimal basic building codes.
Wondering how much snow your roof can hold before you should be concerned about roof Collapse?
This picture can help you calculate snow load on your roof. Now most roofs can handle 20lbs of snow per square foot. This is assuming building codes were followed during construction and that the roof is not rotted underneath.
Here is some things to look for if your roof has too much snow and may begin to collapse.
-Bowed ceilings beneath a flat roof.
-Doors or windows become hard to open or close
-Cracks or lines on your ceiling.
-Cracking and popping sounds.
Please leave your home or building if you notice this and contact local building authorities.
Snow Loads that most roofs are able to withstand typically range from 2 feet of packed snow to over 3 feet fresh fluffy snow before it could begin to be a problem. Now this picture is just an over simplification of a typical house, but each house is different and snow weight can vary drastically depending on the temperature when the snow fell and how compact it gets on the roof. Older snow can get really compact and weight much more than fresh snow.
This chart is just meant to be a very basic understanding of weight on the roof and local building officials and engineers need to be consulted to find out what your exact house can handle in terms of total snow load. Also Drifting can occur on the roof and make some of the roof with practically nothing while the other side of the building have 6 foot drifts. This can be not only over rated capacity for snow load on one side of the building, but also cause the building to twist structurally and actually reduce the ability of the building to hold maximum snow load before it collapses.
The big thing to remember is that Snow acts much like a sponge when rain comes and it is often when building collapse due to rain and water moving around on the roof and not being able to be expelled from off the roof. Another major factor is the amount of ice the melting snow produces, which can cause Ice Dams.
Ice dams can be very destructive to the interior of the building and usually end up becoming the bigger problem than the roof snow itself.
“We get the snow off roofs!”