January 6, 2009 in City, News
Homeowners keep nervous eye on roofs
It’s a question facing homeowners: Is it time to shovel the roof?
For Spokane Mayor Mary Verner, the answer became clear when water found its way into her home.
“My kitchen wall was just a sheet of water,” she said. “The roof isn’t collapsing, but it’s definitely leaking.”
So Monday night, with roof rakes out of stock at hardware stores and no contractors available for quick response, Verner got on the roof and shoveled.
Although Spokane has broken several snowfall records in the past few weeks, the snow load – the weight of snow on the ground – isn’t one of them.
Still, the National Weather Service reported snowfall weights on Tuesday of about 25 pounds per square foot in the Spokane area. Buildings in Spokane are required to meet a 30-pound-per-square-foot snow load. And with 1 to 2 inches of rain in the forecast for Spokane and Coeur d’Alene today and Thursday, many areas could surpass that standard.
Engineers reached Tuesday said the amount means homeowners should look for signs of trouble, but they aren’t necessarily recommending everybody clears off their roof – especially if that means putting untrained people on icy, snowy, pitched roofs without safety equipment.
Engineers avoided making blanket statements about clearing roofs because, they say, there are too many variables based on a home’s construction and design. Other factors include the amount of snow on the roof that already has melted as well as drifting, which could create deeper piles on portions of a roof.
“It’s almost impossible to make generic statements,” said engineer Jeff Van Leuven, who hasn’t cleared off his South Hill roof and doesn’t plan to do so.
A few dozen roofs have collapsed in the Spokane area. Almost all of those have been flat or low-pitched, and officials have recommended that owners of flat-roofed structures clear them. Assistant Spokane Fire Chief Brian Schaeffer said Tuesday that two homes with higher-pitched roofs have collapsed, but they were vacant and had been damaged by fire.
Fire officials have received calls from some homeowners who’ve noticed cracks in walls and other problems related to heavy snow loads. Spokane City Councilman Mike Allen said he hired contractors to clear his roof this week after his front door became difficult to open and a crack appeared in his wall.
Schaeffer said he considered clearing his roof but decided it was too dangerous without access to a roof rake, which can be used from the ground. Officials recommend that homeowners hire licensed and bonded roof clearers if they decide to remove the snow from high-pitched roofs.
“You should consider getting the snow off it, if you can safely do it,” said Joe Wizner, director of Spokane’s building department.
It could be beneficial to hire a structural engineer for an evaluation first, Van Leuven said. That’s because getting on a roof could add an unsafe load, and an engineer could ensure that clearing is necessary.
Owners of homes with high-pitched roofs have solace in a few factors. If a home was around in 1969 and the owner didn’t clear the roof then, it has likely survived a heavier load. Spokane’s record snow weight was measured Feb. 12, 1969, at 36.1 pounds in a square foot, according to the weather service.
“I doubt (older homes) were built to any code, but they have stood the test of time,” said Robert Graper, president of the Spokane chapter of the Structural Engineers Association of Washington.
National Weather Service hydrologist Royce Fontenot said snow loads will increase with expected rain, but at some point melting will reduce weight on roofs. By the end of the rain, weights are expected to have fallen.
Considering the numbers of failures against the tens of thousands of roofs that have thus far withstood the challenge, homeowners should be cautious but shouldn’t panic, said Graper, who hasn’t cleared his roof.
“It’s important that we don’t overreact,” he said.
Wizner said he hopes to gather a group of structural engineers this winter to evaluate Spokane’s roof -load requirements.
“Hopefully, we can learn a lot of lessons when it’s all said and done,” he said.