For Albertans, heavy snow doesn’t come as much of a surprise. But when that snowfall leads to a series of structural collapses, snow turns from an inconvenience to a threat. While these collapses generally occur without casualties, they can still cause significant financial and emotional crises.
In this blog, we take a look at some of the most recent collapses, the common causes of roof collapse, and preventative measures you can take against collapse.
Recent Roof Collapses
Back in 2011, Alberta saw a string of roof collapses. These events struck a senior’s recreation complex, an auto shop, and two furniture stores, among other structures. While few years saw as many incidents as 2011, public building collapses listed below proved that quantity isn’t the only concern.
7 January, 2014 – Whitecourt IGA
Early in the morning, Whitecourt’s IGA supermarket experienced a partial collapse on the east side of the building. The same store experienced a collapse in 2007. In both situations, no bystanders sustained injuries, and fire crews blamed heavy snowfall for the incident.
20 January, 2014 – Sylvan Lake Arena
While resurfacing the ice rink in the arena at 1 a.m., a single employee witnessed this roof collapse. A large portion of the roof caved—the force of the fall blew out the entire underlying wall. The employee escaped without injury. The town’s planning committee intended to tear the 30-year-old centre down and replace it with a leisure centre, but the undignified loss of the structure saddened many of the townsfolk.
Because the arena shared gas and power lines with an adjacent multiplex, crews shut down both buildings and the main nearby streets to prevent further damage.
24 January, 2014 – Drayton Valley Omniplex
Late in the afternoon, the portion of the roof above the club’s curling arena collapsed. Authorities evacuated everyone in the building—no one sustained injuries. Though crews suspected heavy snowfall caused the collapse, they closed the building to conduct an investigation and ensure the collapse didn’t compromise any other portions of the building.
7 February, 2014 – Edmonton CashMoney
When opening staff arrived at CashMoney’s Edmonton location in the morning, they observed damage typical of a partial roof collapse resulting from snow. However, when fire crews arrived at approximately 9 a.m. they discovered that the damage resulted from a failed break and enter. The lending centre closed while contractors repaired the damage.
15 January, 2015 – Rocky Mountain House Barn
Barn collapses often kill huge amounts of livestock and endanger farm workers. One 2014 collapse in Central Alberta claimed over 30 cattle.
Luckily for the Simmelink family, who own a dairy farm near Rocky Mountain House, none of the family members were inside their barn at the time of their own 2015 collapse. Most of the 102 cows inside the barn survived unscathed. The collapse killed six adult cows and five calves, and seriously injured four other cows. The farm’s owner, Devon Simmelink, faced up to $1 million in damages. His insurance company refused to cover the damage because the barn was over 15 years old.
11 April, 2015 – Calgary United Conservatory of Music
When a mezzanine roof collapsed during Saturday morning classes, authorities feared the worst. Fortunately, the debris missed most of the people inside the building at the time. Paramedics treated one little girl after debris hit her during the collapse. While she was upset, the child received no serious injuries.
Causes of Roof Collapse
Most of the collapses listed above link directly to high snowfall and unseasonably high temperatures. The heat melts the snow, creating heavy puddles that strain the roof. According to Sintra Engineering, the three most common causes of roof collapse in Alberta are as follows:
1. Construction Deficiencies
Many collapses occur in older buildings. Often, these roofs exhibit “under-building” or improper maintenance. Issues like layers of re-roofing, insulation without appropriate ventilation, and improper structural modifications often weaken the roof.
2. Ice Damming
Ice dams form along the edges of a roof and prevent snowmelt from draining properly. When standing water stays on the roof too long, it can seep beneath the shingles and compromise the structural integrity.
3. Weight Distribution
Uneven weight distribution results in disproportionate loads across a roof’s surface. This can occur when snow drifts accumulate around protrusions on the rooftops. Flat roofs, such as those commonly found on commercial buildings, don’t lose snow naturally. Without removal, the weight builds and may ultimately cave the roof in.
Safeguards against Roof Collapse
Simple maintenance remains the best way to prevent roof collapse, whether on commercial or residential buildings. During times of heavy snowfall, responsible parties should cautiously remove accumulated snow when it reaches 40 cm (16 in) on residential roofs or 50 cm (20 in) on commercial roofs.
Have a professional roofer conduct regular inspections to ensure your roof stays in good condition. Perform season-appropriate roofing maintenance tasks to prevent ice damming or weight distribution before they take hold, and replace your roof if it’s 25 years old or showing signs of aging.
For more help keeping your roof safe against roof collapse, talk to your local Calgary roofers at Century Roofing Ltd.