In the wake of several commercial buildings in Anchorage collapsing under heavy snow loads this winter, many residents are concerned about the structural integrity of their homes. So far there are no known instances of a house, trailer or multifamily units caving in. The failures have been confined to broad, flat-roofed structures, often warehouses, built in a particular era and with a specific type of wooden roof design that the city has described in detail.
Still, on social media and in real-life conversations, a lot of people have been asking one another if they need to clear their roofs. And if not now, when?
So how concerned should Anchorage residents be? And is climbing up on a ladder in subzero temperatures worth the risk?
We spoke with experts and professionals for answers.
Should you shovel the roof of your home?
It’s not an easy answer. Experts reached for this article — a civil engineer, professional roofers, a building inspector — generally agreed that many homes don’t need it at this point in time, but most shied away from making blanket statements.
They said it’s a case-by-case situation that depends on various factors, including the age of the house, how well it was built, if there are signs of trouble, and whether that roof is flat or steep, known as the roof pitch.
Residential roof collapses in Anchorage are rare, in part because of the relatively high construction and design standards in the building code. And roofs above residential buildings typically cover small areas compared to commercial structures, with more supporting walls spread throughout.
Still, there’s been enough concern with this year’s 104 inches of accumulated snow that the municipality recently issued guidelines that address residential snow-clearing, and warned that some residential buildings might be under stress.
The notice suggested that homeowners consider clearing their roofs, since it’s still early in the winter and more snow will probably fall before things start to thaw and melt.
What are some signs it might be time to clear my roof?
Buildings rarely collapse out of nowhere. There are typically indications that something is wrong before anything catastrophic occurs, so if you’re worried, poke around or contact a professional inspector.
“A building is kind of like a human body, it shows signs of stress when it’s pushed to its limit,” said Scott Hamel, a professor of civil engineering at the University of Alaska Anchorage.
If you see a ceiling beginning to sag, or hear noises like creaks, pops, or cracks coming from the roof area, those could be signs of a problem.
New cracks in drywall or nail heads suddenly popping out may also indicate trouble. Doors and windows that don’t open as easily as they once did are another sign that the structure’s integrity is being compromised by pressure weighing down from above.
Ice dams can also be a problem, increasing the chance that a roof might suffer significant damage or buckle. Big ice dams above eaves can be another indication of a problem beneath the surface of the snow. A big, tall dam at the bottom of the roof may be extending further up, even if you can’t see it, putting pressure on support beams midway up the roof. They can also cause water damage or destroy shingles, gutters or other parts of the house.
My roof is flat. Does that mean it’s at greater risk?
A flat roof can generally support less snow than a steeper roof, making them more prone to buckling under heavy snow loads.
Pitched roofs tend to shed snow better than flat ones. If it’s warm or there’s thawing, water rolls down the declination, compared to flat roofs, which can see water pool, Hamel said. Over time, wind pulls some of the accumulation off steeper roofs. On some flat roofs, wind can rearrange snow into drifted piles, spreading the full weight of the snow load unevenly.
Of course, the higher the angle of a roof’s pitch, the more difficult it is to stand on and clear thousands of pounds of snow off it, and the greater the risk of a fall.
How heavy is the snow right now, and how does that stack up against Anchorage’s building standards?
The design standard for buildings and houses is at least 40 pounds per square foot, and Anchorage is approaching that benchmark, though not there yet.
“I would not say that we are close. We are getting there, and if it snows a whole lot more we’re gonna get closer,” Hamel said.
Hamel hears from an ad hoc community of engineers who measure snow density on buildings across the municipality, which right now, he said, range from 21 to 30 pounds per square foot.
“Buildings will hold more than they are designed for. We don’t operate on thin margins, we’re fairly conservative,” Hamel said.
Does it matter when my home was built?
Ross Noffsinger, the city’s acting head building official, said this week that a house built after 2000 should not require shoveling.
But an older house’s roof might be at higher risk under the heavy snow. Houses built in the 1940s or 1950s, say, should be cleared if the owner is concerned.
The home’s age has less to do with materials degrading over time than it does with building standards, according to Hamel. Prior to 1990, there were solid building codes on the books, but inspection and enforcement were inconsistent, which is why some older homes are at risk.
Noffsinger has said he’s expecting to shovel his own roof once this winter. It’s a Hillside home built in 2000.
Hamel, the engineering professor, said that given the conditions, owners of most homes don’t yet need to worry.
“I would say the risk outweighs the benefit at this point, assuming you don’t have any other red-flag issues,” Hamel said of civilians scaling ladders this winter. “For the regular homeowner who has a well-built house, we’re still pretty far below our snow load.”
Do I need to hire someone to shovel my roof, or can I just do it myself?
Providence Alaska Medical Center treats people each winter who were hurt removing snow from their roof, said spokesman Mikal Canfield. “However, so far the (emergency department) is not seeing more than in a typical year,” he said.
Experts generally say it’s better to hire a roof shoveler, particularly one who is bonded and insured.
“It’s labor intensive, it’s high risk,” said Fred Korevec, owner of Alaska Sourdough Roofing. “There’s the risk of falling, there’s the risk of injuring yourself because it’s backbreaking labor.”
Clearing a roof could take several hours, and that’s likely just the beginning of the project. Snow will probably still need to be cleared off sidewalks and other walking areas below.
Also, it’s important to make sure the cleared snow doesn’t cover up vents on the side of the house.
Most of the experts interviewed for this article emphasized there’s no one-size-fits-all answer, and that individuals are going to need to make a risk assessment for themselves that considers cost, their health and ability, the physical status of their home, and the possibility of more accumulation in the months ahead.
Is there a risk I could damage my roof while shoveling?
Yes. The edges of shovels can hurt shingles or other roof materials, so use caution.
“I repair damaged roofs and people’s shingles all summer long,” Korevec said.
He’s also seen people take mallets to thick ice dams and cause enough damage that sheets of plywood eventually need to be replaced. Hand tools or shovels can dent vents or skylights.
If the person doing the work isn’t insured or bonded, then costs related to personal injuries or damage to the property could fall on the property owner, regardless of who might be at fault.
Courtney Woods, owner of Denali Clearview, a business handling a lot of roof clearing the last few years, says he makes sure to leave a layer of snow in place.
“We don’t take it all the way down to the shingles. You keep 6 inches of snow on there to help with insulation,” Woods said.
It also helps maintain a bit of traction to keep from slipping, particular on roofs with more pitch.
“That’s the safest way in my opinion,” he said.
What should I look for if I want to hire someone to clear my roof?
They should be licensed, bonded and insured, according to the municipality.
There’s lots of them out there, but they’re in high demand this year, with prices all over the board.
“It’s like every single person wants their roof cleared, right now,” Woods said. “We’re falling behind. There’s more snow than shovelers out there.”
Bonded, licensed businesses are more expensive than many of the pop-up operations and individuals offering their services up on social media sites.
Korevec said that even with a crew of four workers, it still takes his team several hours to clear an average single-family home. In part, he explained, that’s because they tend toward more thorough removal techniques, like using a handpick to chisel away at ice dams.
“It costs a little more, but it doesn’t damage the shingles,” Korevec said.