Municipality engineers issue snow removal notice to prevent roof collapses in Anchorage
ANCHORAGE, Alaska (KTUU) - The Municipality of Anchorage is taking action after several wood truss failures led to catastrophic roof collapses last winter, including one death.
The municipality put forward a snow removal notice on Monday for specific buildings in the Anchorage area, in hopes it might prevent more collapses this year.
Municipality engineers estimate the typical roof snow loads in Anchorage are already at 30% to 60% of their total design snow load, with winter only beginning.
Ross Noffsinger, the city’s engineering services manager, said it was important to put forward the notice due to the high volume of moisture-rich snow that’s fallen in Anchorage.
“It can cause catastrophic roof collapse, as we saw in a few cases last year, and we did even have one fatality,” Noffsinger said.
Noffsinger calls it a “very serious” issue and is asking people in the Anchorage area to do their due diligence.
The buildings with primary concerns include commercial buildings, often built before 1990, with wood roof trusses and metal gang nail plates under mostly flat roofs.
“These certain problematic roofs that we’re concerned about, we just wanted to give people a heads up that they should consider to start removing the snow now because we’re going to continue to get more and time matters, too, when it comes to a large weight on a roof,” Noffsinger said.
Noffsinger emphasizes the longer the wood roof trusses are stressed, the more inclined they would be to suffer a failure.
Last year, Noffsinger maintained they had seen one pitched roof failure, which had a complete collapse. He says they saw more top chord bearing truss failures, but also some bottom chord bearing truss failures.
“This era of trusses that we’re concerned about, they seem to have primarily undersized metal connection plates,” Noffsinger said. “The plates should have been bigger to grab more wood, basically, to make a more robust connection.”
So far this winter, municipal engineers are not aware of any roof collapses.
If you decide to hire someone to clean the snow off your roof, Noffsinger says to make sure they’re licensed, bonded and insured.
If you decide to clear snow off a roof yourself, do not move the snow into piles that cause extreme loads in small areas of the roof otherwise it could result in a failure.
Due to limited resources, keep in mind, that a contractor may not be able to be scheduled for a month or two.
If someone notices roof trusses in active failure on a building, it’s recommended to immediately reach out to a structural engineer and the building department with the municipality.
A team of engineers is putting together an investigation of the documentation of various roof collapses that have occurred to learn from them. All of the information gained from the failures is being turned into handouts and policies to better inform people.
The engineers issuing the notice are providing more information on the Municipality of Anchorage website under the development services department page. It has snow removal guidance, as well as details on the wood truss roof investigation.
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