December 30, 2008 in City

Officials urge caution as roof loads deepen

By and The Spokesman-Review
 
Christopher Anderson photo

Craig Crocker, facilities manager for Spokane County Fair and Expo Center, walks past the collapsed roof of the Agriculture A Building on Monday.
(Full-size photo)(All photos)

Fast fact

Most residential roofs are designed to withstand snow equal to 5 inches of rain. So far this month, total snowfall in Spokane has been equal to about 2.5 inches.

The weight from snow and rain caused a partial collapse of the roof at the Rosauers Supermarket at Francis Avenue and Maple Street on Monday afternoon, forcing the evacuation of customers and employees.

Spokane fire officials said as much as 25,000 square feet of roof at the center of the store fell at about 4:30 p.m. No one was trapped by the debris.

Stacy Hayes at Chic-A-Ria restaurant said her business, in the same complex, was closing as of 5:30 p.m.

“They are asking everybody to leave,” she said.

Joan Waters, of northwest Spokane, said she was on her way home from work when she stopped at the store to get a cake for her daughter’s and son’s birthdays this week. While the baker was inscribing the cake, she said, she heard a loud crashing sound coming from the ceiling, followed by several more crashes. People initially started leaving slowly, unsure what was happening.

“One of the managers came out and started screaming, ‘The roof is collapsing,’ ”she said.

“The store was not that crowded, so there was not a major traffic jam at the front door.”

Snow also collapsed a roof on part of a building at the county fairgrounds over the weekend, as well as more than a dozen other structures around the city of Spokane.

But a city fire official cautioned homeowners against climbing on their roofs with a shovel to try lightening the load.

“It’s usually risky and it’s ill-advised,” Assistant Fire Chief Brian Schaeffer said. “Even for us, getting on the roof is incredibly dangerous.”

Most of the problems occurred with structures that have flat or arched roofs, or carports, Schaeffer said. Most residential roofs are built to withstand more snow than Spokane has experienced so far.

If a roof is sagging or showing other signs of stress, Schaeffer advised contacting a structural engineer, and if the snow needs to be removed, hiring a licensed contractor.

In Coeur d’Alene, Deputy Fire Chief Glenn Lauper said his department was responding with a building department official to calls from residents concerned about the safety of their roofs. A structural engineer is recommended for businesses, he said, and drains plugged by ice may be a problem on some roofs, he said.

As for homes, Lauper said the department would likely recommend removing snow.

Structural engineer John Cuddy said a house in good condition probably could withstand three feet of snow. Roof failures typically occur when a secondary problem arises, such as blocked or frozen roof drains and an imbalance in weight caused by wind blowing snow off one portion of the roof and depositing it on another, he said.

Most houses are designed to hold between 30 and 40 pounds of weight per square foot. Roofs up to code should hold snow that equals about 5 inches of water if melted. The National Weather Service said the snow that has fallen thus far in Spokane is equivalent to about 2.5 inches of water.

Cuddy said that there are so many types of roof geometry that it is difficult to make any generalizations about the safety of any one structure.

The roof on the west annex of the Agriculture A Building at the Spokane County Fair and Expo Center collapsed Friday, and wet snow has compromised the structure under the roof for the east annex.

The building was empty and no one was hurt when the roof collapsed, Facilities Manager Craig Crocker said Monday. A week ago, the building was the site of The Spokesman-Review Christmas Bureau’s food voucher and toy distribution operation.

County officials are waiting for an inspection by a structural engineer to determine what parts of the building are salvageable, Crocker said.

In a separate move late Monday morning, the county ordered employees to evacuate the Information Systems Department building because of snow load and a risk of collapse, said Dorothy Gallarda, an administrative assistant at Spokane County.

In Coeur d’Alene, several boats at the Conkling Park Marina were damaged over the weekend when a section of roof collapsed from the weight of the snow.

The collapse occurred in a section of marina that is privately owned by a condominium association, said Pat Dean, who has stored his boat in the public area of the marina for many years.

Mike Gilbert, who also stores his boat at the marina, said some boats were pushed completely underwater and that only the bows of others were visible. Boats are covered in the debris from the metal-roofed wooden structure that collapsed.

“It’s too dangerous to try to enter,” Gilbert said.

“Given the weather conditions, no one knows when they’ll be able to get that debris off the boats. Luckily, no one was hurt.”

Staff writers Alison Boggs and Thomas Clouse contributed to this report.


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