February 18, 2011

Snow followed by warm weather prompts Edmonton to inspect roofs on city-owned buildings

RICHARD GILBERT

joc staff writer

The City of Edmonton launched inspections on all city-owned buildings, after a roof collapsed at a seniors’ home from the weight of melting snow.

“We do this every year, but this is the first time we have had to go to this extent,” said Paul Specht, director of buildings and facilities maintenance with the City of Edmonton.

“Some staff have not experienced this in 35 years with the city.”

Edmonton was hit by a major winter storm that dumped around 25 to 35 centimetres of snow between Jan. 7 and Jan. 9.

The accumulation of snow throughout the month caused the roof and auditorium wall of the Northgate Lions Senior Recreation Centre to collapse on Jan. 25.

When the ceiling began to creak and buckle, about 150 seniors were evacuated. No one was injured.

“Snow was a factor, but not the cause,” Specht said. “We started our snow emergency roof program prior to the roof collapse.”

Specht said the major concern was the warm weather following snowfalls.

“The snow was not the problem, but melting snow can contribute to structural problems,” he said.

“Melting snow can cause problems for water accumulation, because the water can’t get off the roof. This will add weight or change the weight distribution and lead to the stressing of the roof members.

“These conditions developed in a short period of time.”

Snow distributes evenly. But when it melts, water can gather in one area, leading to potential collapse.

As of Jan 31, City of Edmonton staff had inspected 440 buildings.

Out of those buildings, there were a number where snow had to be shovelled off the roof to give staff access to roof equipment.

“On some buildings there was an accumulation of snow between five to eight feet,” said Specht. “At the same time, city staff looked for plugged roof drains and found that some drains were blocked by ice and debris.”

About 30 staff worked on the inspections, including a good portion of the city’s carpentry crew. Contractors were also hired to do the snow clearing.

“We only found two buildings where we brought in a city engineer to inspect the amount of deflection or sagging on the roof,” said Specht.

The inspectors talked with city staff to see if they had observed or heard any warning signs, including cracking sounds and other strange noises coming from the ceiling or walls.

The Edmonton area experienced a string of snow-related roof collapses last month.

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