How Much Does Snow On A Roof Weigh?

We’ve all seen the pictures and heard the stories of roofs collapsing after large snow storms.  A February record of 42 inches of snow has already fallen on Boston. So, how much DOES snow weigh?

A one-inch layer of water or ice weighs approximately five pounds/square foot. Roofs designed for about 20 pounds/square foot snow load could theoretically hold up to four inches of ice.

How much snow is that?

Estimates are that about 12 inches of snow is equivalent to one inch of water, which means a roof can hold up to four feet of snow. Wet and packed snow weigh more, meaning that a roof may only be able to hold up to three feet of wet and packed snow.

So what do you do if you have too much snow on your roof?

The simple answer is to get it off as soon as possible. Snow rakes are available at local hardware stores and can be used to remove snow. If using a snow rake, use caution when working near overhead electrical power lines. Also, avoid excessive scraping on the roof or trying to chip off the ice. This could damage the roof and lead to a roof leak.

SMART Roofing, Inc. is a full service roofing contractor serving Chicago and its surrounding suburbs. From roof assessments and repairs to installations of virtually every type of new residential roof and commercial roof, our commitment to excellence, stellar customer service and exceptional results are the “SMART” roofing difference.