February 6, 2014By: Douglas Trattner
Wet snow is much heavier than dry, fluffy snow. Six inches of dry snow weighs about as much as 38 inches of wet snow. Image: Zvozdochka/iStockphoto
If you’ve had a big snowfall in your area and you’re wondering if your roof can stand the extra weight, don’t reach for a ladder and a shovel — reach for the telephone. Calling in a professional to remove ice and snow from your roof is the smartest — and safest — option.
When (If Ever) is it Necessary?
The critical factor in determining excessive snow loads on your roof isn’t the depth of the snow, it’s the weight, says home improvement expert Jon Eakes.
That’s because wet snow is considerably heavier than dry, fluffy snow. In fact, 6 inches of wet snow is equal to the weight of about 38 inches of dry snow.
The good news is that residential roofs are required by building codes to withstand the heaviest snows for that particular part of the country.
“Theoretically, if your roof is built to code, it’s built to support more than the normal load of snow and ice,” says Eakes.
You can determine the type of snow you’re getting simply by hefting a few shovelfuls — you should be able to quickly tell if the current snowfall is wet or dry. Local winter storm weather forecasts should alert you to the possibility that snow loads are becoming excessive and a threat to your roof.
How Do I Know There’s a Problem?
An indication that the accumulated snow load is becoming excessive is when doors on interior walls begin to stick. That signals there’s enough weight on the center structure of the house to distort the door frame.
Ignore doors on exterior walls but check interior doors leading to second-floor bedrooms, closets, and attics in the center of your home. Also, examine the drywall or plaster around the frames of these doors for visible cracks.
Homes that are most susceptible to roof cave-ins are those that underwent un-permitted renovations. The improper removal of interior load-bearing walls is often responsible for catastrophic roof collapses.
The Snow Load Seems Excessive, Now What?
Most home roofs aren’t readily accessible, making the job dangerous for do-it-yourselfers.
“People die every year just climbing ladders,” Eakes points out. “Add ice and snow and you’re really asking for trouble.”
Instead, call a professional snow removal contractor to safely do the job. Check to make sure they are licensed and insured — that immediately sets them apart from inexperienced competitors.
Pro crews attack snow removal with special gear, including sturdy extension ladders, properly anchored safety harnesses, and special snow and ice-removal tools. Expect to pay $250-$500 for most jobs.
Don’t expect (or demand) a bone-dry roof at job’s end. The goal is to remove “excessive” weight as opposed to all weight. Plus, any attempt to completely remove the bottom layer of ice will almost always result in irreparable damage to your roofing.
The DIY Option
If you have a small, one-story bungalow where the roof is just off the ground, taking matters into one’s own hands may be safe — if you can work entirely from the ground and have the right tools.
Long-handled snow rakes work great on freshly fallen snow, and at $45 they are relatively affordable. Look for models with sturdy telescoping handles and built-in rollers, which keep the blade safely above the shingles.
Other versions work by releasing the snow from underneath. These models slide between the roof and snow, allowing gravity and the snow’s own weight to do most of the work. Models range from $50-$125 or more for unique systems utilizing nylon sheeting. Again, search out models with sturdy adjustable handles.
Eakes offers a common sense word of caution about all these snow removal tools. “They tend to work their best on light, fluffy snow — the kind that probably doesn’t need to be removed in the first place.”
You’ll need to anticipate where the snow and ice will fall as you pull it off your roof — you won’t want to pull a load of heavy, wet snow down on top of yourself or any helpers.
Remember, the goal isn’t to remove all visible snow and ice, but rather just enough to relieve the excessive load on the roof.
Douglas Trattner with House Logic