Tornado blows change through Ontario bylaws

Six tornadoes that swept through Barrie and other Ontario communities in mid-July have brought the issue of building code changes to the forefront.

The communities of Barrie, Innisfil, Kawartha Lakes, Little Britain, Manilla, Lindsay, and Lake of Bays were all hit by the tornadoes on July 15. The EF2-strength tornadoes — meaning winds speeds between 178 km/h and 217 km/h — caused $75 million in insured damage, according to preliminary estimates from Catastrophe Indices and Quantification Inc. (CatIQ).

Just days after the tornado in Barrie, local Coun. Natalie Harris said she would put forward a motion to have the city propose amendments to the Ontario Building Code to better protect buildings against severe winds. She also told the Canadian Press she wanted to ask the City of Barrie to bring in a bylaw mandating hurricane straps for roofs on new local properties.

Glenn McGillivray, managing director of the Institute for Catastrophic Loss Reduction (ICLR), told Canadian Underwriter the motion was tabled on the evening of Aug. 9 and passed unanimously. It calls on the City of Barrie to work with ICLR on three initiatives:

1. To push the Ontario government to change the building code by requiring hurricane straps in all new builds;

2. To launch a tornado mitigation awareness program; and

3. To look into rolling out an incentive program encouraging builders to use hurricane straps until such time that they are added to the code.

Hurricane straps, which cost about $1 to $2 each, plus labour to install, would add about $200 to the cost of an average home, McGillivray said. The straps are designed to keep a roof on a home even in EF2 winds.

“The vast majority of tornadoes in Canada rate between EF0 and EF2, so adding hurricane straps will handle the majority of tornado events,” McGillivray said. “Generally, once a roof has been removed from a home, it is a write-off due to concerns centring around structural integrity.”

Two days after the tornado struck Barrie, the city said 71 homes were “deemed unsafe to enter.” Ten people were injured and there were more than 2,200 insurance claims for damage to personal and commercial property, Insurance Bureau of Canada (IBC) reported.

“We’re beyond thankful that this storm did not lead to any loss of life, which is the most important thing,” Kim Donaldson, vice president of IBC’s Ontario region, said in a press release. “Homes, cars and businesses can be replaced and fixed, but the same cannot be said of lives.”

The Canadian Press reported that the tornadoes not only blew roofs off houses, but collapsed walls and caused power outages. House and car windows were also smashed. Environment and Climate Change Canada said the damage path of the tornado that hit Barrie was about five kilometres long and up to 100 metres wide, with maximum wind speeds of 210 km/h.

Even though hurricane straps are not mandated in Ontario’s building code, builders can voluntarily use straps until they are included in the code, McGillivray said. “It is important to note that the building code does not prevent builders from using hurricane straps right now.”

Dufferin County encourages the use straps by paying builders $4.50 per strap, McGillivray said. ICLR is also working with home building company Doug Tarry homes to put straps and other wind resilience features in a new subdivision in St. Thomas, Ont.

Even though ICLR wants to see Ontario’s building code changed to include a hurricane strap requirement, there are other things builders may have to do in tandem with this, McGillivray said. A number of actions that can be taken to reduce the impact of winds on homes, include:

•  Using hip roofs (preferable to gable roofs for reducing exposure to high-wind impacts). When gable roofs are used, measures can be applied to ensure gable end walls are reinforced and well-connected to the structure, and therefore are capable of resisting wind loads;
•  Employing slightly thicker roof sheathing (11.1 mm or 7/16” in lieu of 3/8” sheathing), combined with 63 mm (2.5”) nails that are spaced 150 mm (6”) apart along both the edges of the sheathing panel and along the interior supports, reduces the risk of damage associated with sheathing failure; and
•  Ensuring the building is securely fastened to the foundation using anchor bolts.

Feature image via iStock.com/solarseven