UWO engineer says tornado damage in Barrie would have been less if building code followed

City of Barrie says claim by engineer 'casts a misleading shadow'

A back-and-forth debate has begun over whether building code protocols were followed in the wake of Thursday’s tornado in southeast Barrie.

Greg Kopp is with Western University’s Northern Tornadoes Project (NTP) and a professor of civil and environmental engineering. He maintains there would have been less damage in Barrie had the building code been followed.

Kopp told Barrie 360 some of the roofs weren’t attached properly to the walls.

“We saw numerous examples of that in Barrie, this time. There’s a few places where it looked like there was no nails, or one, where the code requires three. You just have much less strength there.” Kopp told Barrie 360. “We believe some of the damage would have been much reduced if the code had been properly adhered to in those cases.”

“The building code required those nails to be there. There still would have been significant damage in Barrie, but it would have been reduced.”

The number of homes that may be condemned in the wake of the tornado is still being counted, and some of those lost roofs.

Tornado damage – Barrie – July 15, 2021/Barrie 360

“Suggestions that the homes in Barrie affected by Thursday’s tornado did not follow code casts a misleading shadow on the excellent work of our registered building professionals as well as the broader building industry,” the city said in a media release on Monday.

“We want the people of Barrie to know that we take the safety of all residents seriously and every effort is made to ensure compliance with the building code.”

In the statement, the city says it’s unreasonable to expect a roof to resist tornado strength winds and resulting forces when they are not required to be designed for that.

Kopp acknowledges the building code does not require homes to be resistant to tornadoes.

“The building code is mostly silent on tornadoes,” he says.

Kopp says when a tornado wants to lift the roof off of the house, then you have to think about holding the roof down. Wood-frame houses have very light roofs and so you need pretty good fasteners do that.”

Tornado – Barrie – July 15, 2021/Barrie 360

He says our houses are built really well for energy efficiency but not so much for wind performance.

Environment Canada confirmed the tornado that tore through Barrie was a category EF-2 tornado with a maximum wind speed of 210 km/h.

“It is unreasonable to expect a roof to resist tornado strength winds and resulting forces when they are not required to be designed for that. Some of the winds were strong enough to lift and move the entire weight of a house, so it is not surprising that roofs were removed in their entirety. Also, once a roof is compromised, the effects of the loading it is subjected to becomes even more damaging,” the city added in its statement.

“It is clear a tornado imposes loads much more severe than those specified in the building code. The building industry (including designers, engineers, building officials and code researchers and writers) recognize this. There are continuous efforts to update and upgrade the code.  The building industry works with the province to review and update various aspects of the code. This is one area that certainly can use some attention. The work like that being done by the Northern Tornadoes Project researchers will certainly be valuable as the province considers updates to the code. The city supports sharing these findings with the Province and National Code researchers to facilitate improvements to the code.”

Kopp says what his team uncovered in Barrie isn’t new.

“What we found in Barrie we have seen in other places,” he explains. “We saw the same thing in the Angus tornado a few years ago and other places in Canada. One of the important details is how the roof is fastened to the walls, and often those aren’t done correctly.”

He says some things have been added to the building code in the past for tornadoes including how the house is bolted to the foundation.

“That resulted from tornadoes in the 1980s where houses weren’t bolted down. They were cottages and the whole house actually lifted off and was thrown into a lake, and someone was in it and drowned.”

Kopp says houses can be designed for tornadoes of the intensity Barrie experienced for a relatively low cost. He says the technology was designed in the U.S. for hurricanes.

“They are hurricane straps that you can use to hold the roof to the walls. It costs in the order of a couple of hundred dollars per house when it’s new to put in,” Kopp says. “It would hold the roof onto the walls in these kinds of tornadoes up to this intensity.”

He says the province needs to move on this.

“We’ve put proposals in the path of the Ontario Building Code about exactly this issue and they were declined. I don’t recall the rationale for why that was. The codes have an interesting process and that’s a whole different conversation.”

For Kopp, this is a life and safety issue.

“I think we expect our structures to hold together. I think of you put hurricane straps in, I don’t think the cost is so high to be problematic, and it’s much easier to inspect because you don’t have to go up onto a ladder and inspect every connection.”

“Do we want to design houses to stop all damage from tornadoes? We probably don’t want to pay that.”

NTP is working with a builder (Doug Tarry) in St. Thomas on exactly what Kopp and his team have recommended.

“He’s taken our recommendations from the lab and is implementing them in practice. We’ve worked with the builder to make a relatively simple set of suggestions for improving the performance and we’re learning from his experience, such as what the issues are with implementing it so it could be implemented in the code,” says Kopp.

“He makes very energy-efficient homes. He also realizes that if we’re going to make energy-efficient homes, we also want them to be resilient at the same time. It doesn’t help us when homes end up in the landfill.”

Barrie Mayor Jeff Lehman says there are pieces to consider.

“One is, you know, is the building code strong enough? Is it strong enough in terms of its requirements for attaching roofs to walls? I mean, they’re just nailed on, right? Secondly, was there ever a situation where the work was not done correctly when the home was built that could have contributed in some way?”