Fire investigators say a blaze above Stella's on Sherbrook Street Thursday night was caused by spontaneous combustion of spray foam insulation being installed in the attic.

A fire official said Friday morning that damage is estimated at $700,000.

Emergency crews were called to the building that houses the popular restaurant, which was quickly evacuated, around 8 p.m. Thursday.

The street was blocked to traffic from Westminster Avenue to Broadway and taped off for pedestrians as well.

No one was injured in the fire, police said.

"No one was affected other than being able to finish their pasta and their wine," said Megan Verrier, the general manager of Stella's on Sherbrook.

The location on Sherbrook has 26 front-of-house staff, five managers and 14 back-of-house employees Verrier said, adding 35 customers were cleared out the night of the fire.

Verrier said the company has already noticed more customers than usual at other locations. That increase in traffic has allowed Verrier to find hours for her staff at other locations, she said.

Stella's appreciates the support it's been receiving from the community, Verrier said.

"The community has been amazing. We look forward to just reopening ... and treating everyone the way they've treated us — with warmth, comfort and happiness."

Commonly used

Spray foam insulation is very common on modern construction projects and is a great material to use with wood construction, said Marten Duhoux, a principal with FT3 Architecture, Landscape and Interior Design in Winnipeg.

"I don't think I have any projects that don't use it," he said.

Duhoux said none of his projects have ever had a problem with spray foam insulation, but he has heard of fires happening.

"This kind of thing happens. It's just a reminder for the public that you want people with experience [installing the foam]," he said.

FT3's building specifications require spray foam installers to have a certain level of experience, Duhoux said.

Having experienced people "isn't a guarantee that it won't happen, but it will be less likely."

Highly regulated

Keith Bowie, the owner of Ecology Spray Foam, said what happened at Stella's is "extremely rare."

Bowie estimates there are roughly 600,000 buildings across Canada that have spray foam insulation. In his eight years in the business, he hasn't heard of anything like what happened at Stella's Thursday night.

"We're one of the most regulated sub-trades in the construction business," said Bowie.

"In order to buy foam you have to be certified, you have to go through a certification training process.... We have to in fact get re-certified every five years — most trades don't have to do that."

Builds up heat in some cases

Linda King of Penta Coatings, which has been installing foam insulation for 27 years, said spray foam insulation is safe as long as the work is done properly.

The insulation should be applied in two-inch passes and allowed to cool before another layer is added, King said.

Not allowing it to cool properly could trigger a chemical reaction that builds up heat, she said.

"It's combustible. It will build up heat, and not in all situations, but depending on how thick it is, yes, it will build up heat and can catch fire," she said.

"I've heard of it, but this is the first one I've heard of in Winnipeg."

Penta Coatings was not the company hired to install spray foam installation at Stella's on Sherbrook Street, King added.