With winter storms coming almost continuously in some areas this season, heavy snow and ice strains roofs and puts one at risk of significant property damage.
The Insurance Institute for Business & Home Safety offers four steps to preventing costly roof damage caused by long stretches of severe winter weather. The organization also states it's important to inspect the roof of a garage, shed, porch or any other structure that has had to carry the weight of this winter's severe weather.
"Proper maintenance and care is critical to avoiding significant property damage due to severe winter weather," said Julie Rochman, IBHS president and CEO. "If snow and ice piles on your roof, it's important to safely remove it by staying on the ground using a snow roof rake. If you don't feel comfortable doing so, call a professional contractor to help you safely remove the heavy snow and ice."
IBHS also encourages homeowners to stay tuned to local news reports and alerts from the National Weather Service for information about impending severe winter weather storms.
Four steps to reducing your roof risks during severe winter weather
1. Evaluate your risk: Melting snow tends to more quickly run off steep sloped roofs with slopes greater than 3 inches of slope in 12 inches of horizontal distance, particularly the steeper ones that are typically found on houses in northern climates.
•Ice and snow tend to more readily accumulate on low slope and flat roofs over porches, lanais or parts of a home that are next to a taller section of the house, especially during high winds.
2. Estimate how much weight your roof can support: Unless the roof structure is damaged or decayed, most residential roofs regardless of the location of the house should be able to support 20 pounds per square foot of snow before they become stressed.
•In some areas of New England and in mountainous areas throughout the U.S., snow loads used in home design may be considerably higher, and the roofs may be able to resist a greater depth of snow.
•If you live in an area known for lots of snow, you can probably check with your building department to find out if higher loads were used at the time your home was built.
3. Estimate how much the snow on your roof weighs
•Fresh snow: 10-12 inches of new snow is equal to 1 inch of water, or about 5 pounds per square foot of roof space, so you could have up to 4 feet of new snow before the roof will become stressed.
•Packed snow: 3-5 inches of old snow is equal to 1 inch of water, or about 5 pounds per square foot of roof space, so anything more than 2 feet of old snow could be too much for your roof to handle.
•Total accumulated weight: 2 feet of old snow and 2 feet of new snow could weigh as much as 60 pounds per square foot of roof space, which is beyond the typical snow load capacity of most roofs.
•Ice: one inch of ice equals one foot of fresh snow.
4. Remove snow from your roof: If you are in the "danger zone" according to this chart (PDF download), or if the loads you estimate based on the thickness of the various types of snow and ice exceed 20-25 per square foot, you should consider removing snow from your roof.
•For safe removal that won't endanger you or damage your roof, use a snow rake with a long extension arm that will allow you to remove the snow while standing on the ground, or hire a snow removal contractor.
The Insurance Institute for Business & Home Safety is an independent, nonprofit, scientific research and communications organization supported by the property insurance industry. The organization works to reduce the social and economic effects of natural disasters and other risks on residential and commercial property by conducting building science research and advocating improved construction, maintenance and preparedness practices.