“It’s something that senior construction officials across Ontario had previously discussed at length,” said an official from the home owners association
Would the so-called hurricane lacing have prevented some roofs from being blown up from houses in the south of Barrie during last Thursday’s tornado? It depends who you ask.
Hurricane straps connect and reinforce wood-framed roofs and houses, the most common of which are made of galvanized or stainless steel. They are intended to help protect buildings from the elements.
Paul Meredith, first vice president of the Simcoe County Home Builders’ Association and a professional construction manager, said there were two arguments.
“It’s something that construction managers across Ontario have previously discussed at length,” he said. “For the cost of the hurricane belts, yes. And the short answer is yes, you would think it would make sense.
“Would it cause the house to collapse even more, however? If the hurricane belts were attached there it would have caused a possible collapse, trapping or injuring people in the house, so there is a two-way argument. “
Meredith says hurricane bands are not required by the Ontario Building Code but are an option.
“The designer who would be with the truss company will specify how these trusses will be installed and secured,” he said. “If you were building a house, you would request the truss package from an engineer or truss company whose engineer would specify how to install and secure these trusses.”
A truss is a prefabricated wooden structure that incorporates triangular webbing to support the roof above while also connecting the exterior walls of the house together.
Ontario’s Department of Local Affairs and Housing says a number of factors need to be considered.
“Today’s builders can use hurricane clips (or strapping) if they want,” said Department spokesman Matt Carter. “The Ontario Building Code sets minimum requirements for the design and construction of buildings, and those minimum requirements must be met or exceeded.
“The building code currently contains provisions according to which roof structures of buildings must be attached to the load-bearing walls in such a way that they can withstand buoyancy forces,” he added. “The code also defines binding minimum requirements for anchoring various building components – including rafters, trusses and roof cladding – in houses and small buildings.
“For larger buildings, the code sets the minimum wind loads a building must withstand based on geographic location and other factors that affect the wind forces that the building is likely to experience during its lifetime,” said Carter. “These requirements are based on the requirements of the Canadian National Building Code.”
So there is no absolute answer to the benefits of hurricane strapping in severe weather. According to Environment and Climate Change Canada (ECCC), wind speeds during the tornado reached 210 kilometers per hour on Thursday.
“There is a difference between complying with building codes, which set minimum construction requirements, and building that is tornado-resistant – This is a much higher standard than the building code stipulates, ”said Andrea Miller, General Manager of Infrastructure and Growth Management at Barrie, on Monday.
“It is unreasonable to expect a roof to withstand tornado winds and the forces that result from them if they are not designed to withstand them,” she added.
However, Greg Kopp, a wind engineer with Western University’s Northern Tornadoes Project, found that some of the roofs were not properly attached to the walls and that he believes building codes were not being followed.
David Philips, chief climatologist at the ECCC, recommends hurricane harnesses.
“We know we don’t live in hurricane areas, but what would you have to do to ask builders to put hurricane tapes on roofs and upper floors,” he said. “I mean, there’s only about 25 or 30 cents to invest, although the work may be extra. It offers this additional protection. ”
Barrie councilor Natalie Harris, who rode out the tornado in a house that had lost its roof, said she discussed the issue with Kopp, an engineering professor at Western University and a senior researcher with the Northern Tornadoes Project. Harris said she would take the issue to the city council, which will next meet on August 9th.
“For the time being, I’m going to ask the Ontario government to amend the Ontario Building Code to include mandatory hurricane harnesses in areas where tornadoes are evident,” she said Monday, “and that the city of Barrie need to add a clause that all new construction projects must contain. ” Hurricane straps as recommended by Mr. Kopp. “
City officials say they will not know the number of homes damaged by the tornado until a full assessment is completed.
A total of 75 unsafe orders had been issued and eight had been removed by 6 p.m. Sunday.
Unsafe orders have been issued that are posted on houses with significant structural damage, which is part of the city’s obligation under the Building Code.
The number of buildings classified as unsafe will change as soon as more detailed information on the damage to the structures is available. A professional engineer must assess the damage to any property.
A severe storm, strong wind, and a possible tornado hit the northern edge of Sandycove Acres in Innisfil on Thursday afternoon. No injuries were reported.