Snow is continuing to pile up across the Midwest and Ohio Valley, with more than 20 inches expected this week in certain parts of the Great Lakes.
The Insurance Institute for Business & Home Safety offers four steps to help prevent costly roof damage as a result of long stretches of severe winter weather, especially snow.
"We have seen record amounts of snow and ice this year," said Julie Rochman, IBHS president and CEO. "This could pose a serious risk to roofs that are already feeling the weight of winter snow."
"Snow accumulation on buildings can result in more than just loss of electrical power or wear on the roof," Rochman said. "Buildings may be at risk of collapsing if basic preventative steps are not taken."
The Insurance Institute for Business & Home Safety offers the following four steps to determine the risks to a roof, how to address those risks, and finally how to identify possible warning signs that a roof is under too much stress.
Reduce Snow Load Risks
Step 1: 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.
What is pounds per square foot?: A square foot is a square where all sides equal 1 foot, while pounds per square foot is the amount of weight in that square. If you have about 10 inches of snow on your roof, that equals to 5 pounds per square foot of space on your roof.
- In some areas of New England and in mountainous areas throughout the United States, the amount of snow a roof was designed to handle before being damaged may be considerably higher than other locations. Check with your building department to find out if your home was built at a time when homes were designed to withstand higher amounts of snow.
Step 2: Estimate how much the snow on your roof weighs.
Fresh snow: 10 inches to 1 foot 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. 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 two 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: 1 inch of ice equals 1 foot of fresh snow.
Step 3: Remove heavy snow and ice.
Consider removing snow if it exceeds 20-25 pounds per square foot.
For safe snow/ice removal that won't endanger you or damage your roof, use a non-metallic snow roof rake with a long extension arm that will allow you to remove the snow while standing on the ground. If you feel uncomfortable removing snow yourself, hire a snow removal contractor.
Use the following additional information from the Federal Emergency Management Agency (FEMA) to safely remove snow from your roof:
- Always have someone below the roof to keep people away from locations where falling snow or ice could cause injuries.
- Ensure there is no equipment below that could be damaged by falling snow or ice.
- Whenever snow is being removed from a roof, be careful of dislodged icicles. An icicle falling from a short height can still cause damage or injury.
- When using a non-metallic snow rake, be aware that roof snow can slide at any moment. Keep a safe distance away from the eave to remain outside of the sliding range.
- Keep in mind that buried skylights pose a high risk to workers on a roof who are removing snow.
- Removing snow completely from a roof surface can result in serious damage to the roof covering and possibly lead to leaks and additional damage. At least 2 inches of snow should be left on the roof.
- Do not use mechanical snow removal equipment or sharp tools.
- Do not let snow build into piles on the roof, but if you do, remove them first.
- Once piles of snow have been removed, start remaining snow removal from the center portion of the roof.
- Keep snow away from building exits, fire escapes, drain downspouts, ventilation openings, and equipment.
Step 4: Identify warning signs of an overstressed roof.
Buildings made of wood and steel may show noticeable signs of wear and damage before failure, according to FEMA. Use the following warning signs from FEMA to identify common issues seen in wood, metal, and steel constructed buildings:
- Sagging ceiling tiles or boards, ceiling boards falling out of the ceiling grid, and/or sagging overhead sprinkler lines and sprinkler heads.
- Hanging sprinkler heads below suspended ceilings.
- Popping, cracking, and creaking noises.
- Sagging roof parts, including metal decking or plywood sheathing.
- Doors and/or windows that can no longer be opened or closed.
- Cracking or splitting wood.
- Cracking walls or masonry.
- Leaking roof.