Anchorage Spenard Builders Supply facility suffers major snow-related roof collapse

An Anchorage Spenard Builders Supply facility suffered a large-scale roof collapse late Wednesday night, according to the Anchorage Fire Department.

Assistant Fire Chief Alex Boyd said Thursday morning that nobody was in the former truss plant, currently being used by the construction supply company as a dispatch center, when the collapse was reported shortly before 11 p.m. Wednesday. No injuries have been reported in the incident on West 46th Avenue, about a block west of the main SBS store.

Boyd said the building was severely damaged in the collapse, but firefighters haven’t declared it a total loss pending further assessment by structural engineers.

At the scene, much of the structure’s roof appeared to have failed, leaving long sections of its walls open and the contents of the building visible. Water from a broken water main was pooling on snowy streets, and debris was lying in the roadway along one side of the plant.

A resident of a nearby home, John Crews, said the force of the collapse blew roof tiles from the plant across West 46th into his driveway.

“It was like a giant windstorm,” Crews said.

Boyd said the plant was being used to store trucks and assorted supplies. He said snow and ice loading are believed to be factors in the collapse, noting that winds and freeze-melt cycles can gather snow in drifts or form ice dams that increase weight at particular points on a roof.

“(Determining) the cause will require some engineering review and structural engineers to actually look at the debris as they pull it out to determine where the point of failure occurred first,” Boyd said. “So it’ll be some time.”

After consulting with municipal engineers overnight, Boyd said firefighters are recommending that any owners of commercial buildings similar to the collapsed plant — large, flat-roofed, parallel-chord-truss warehouses built in the 1980s — “pay very, very close attention to snow loads and snow removal.”

“There is concern that those buildings are not able to stand up to the designed snow loads for the city of Anchorage,” Boyd said.

Firefighters don’t believe residential structures built to municipal code are in “extreme danger” of roof collapses, Boyd said. He urged any residents concerned about snow load to contact the municipality’s Development Services office or commercial engineers.

Sixteen fire crews initially responded to the collapse, Boyd said. Firefighters and police formed a perimeter around the plant until gas, water and electric lines to the building were shut down remotely by about 2:30 a.m. Thursday.

According to Boyd, the truss plant marks Anchorage’s first major roof collapse this winter. Several collapses took place across town last winter, including one at a South Anchorage CrossFit gym that left a woman dead.