Firefighters across Ontario have a new hazard to deal with right below their feet.

Pre-engineered floor joists, made from wood chips and glue, burn twice as fast as traditional wooden joists and can suddenly collapse from beneath the first responders.

According to Tim Beckett, fire chief of the Kitchener fire chief and president of the Ontario Association of Fire Chiefs (OAFC), traditional floor joists burn in 15 minutes. Pre-engineered joists do so in approximately six.

Beckett said the average response time of a fire department is between four and six minutes, depending on the area of Ontario.

'We're looking at floor failure before we even arrive.'— Tim Beckett, president OAFC

"What we’re finding with the new joists ... is that you can failure in as little as four to seven minutes," Beckett said. "We’re looking at floor failure before we even arrive on scene."

Beckett called the use of the new joists "widespread."

Citing a study by the National Research Council of Canada Institute for Research in Construction, Barry Malmsten, the executive director of the OAFC, said the joists have changed the way firefighters attack a fire and rescue people from burning homes.

"When you arrive and it's fully engulfed, there's not a lot you can do," Malmsten said.

He said some departments have stopped entering the front doors of newer burning homes to rescue people and attack fires. Instead, they choose to rescue people through windows, using ladders.

Firefighters now choose to rescue people using ladders and buckets. (CBC News)

Beckett said he knows of instances where crews haven't entered a home.

"Health and safety of the crew is primary. We may choose to not go inside the house," Beckett said.

Beckett said fatalities linked to the floor joists failure are "quite common” in the U.S. but he doesn't know of any in Canada. He did say that "light-weight construction" was partially to blame in the death of two volunteer firefighters in Listowel, Ont., where walls collapsed onto them in March 2011.

Mapping new homes

Lakeshore, Ont., fire chief Don Williamson said the joists have forced his department to use geographical information system (GIS) mapping to track new homes built in the area.

Williamson said firefighters are much more hesitant to go into burning houses. He also said the joists don't even have to be on fire to be considered dangerous. High heat melts the glue that holds the wood together and makes it unstable.

Bob Blais, who owns Blais Construction Management Ltd., has been a contractor building homes for 35 years. He uses both pre-engineered joists and traditional joists. He said new home builders want open concepts, which mean longer floor spans. Only pre-engineered joists allow for longer spans.

Pre-engineered floor joists are made of wood chips, resin and glue pressed together in the shape of a steel I-beam. They are fabricated to support longer spans. (Blais Construction Management Ltd.)

"Conventional, to me, is still the best way to go," Blais said.

He also knows "firefighters already have their hands full."

"I think a simple sticker, like ‘pets in the home,’ would be a solution," Blais said. "A fireman should know what the home is constructed with."

Beckett and Malmsten each said the toxicity rates are higher in fires today because of the glues and resins used. They said smoke in today's homes is thicker, heavier and is produced faster.

"The fumes have so many toxins in them, they’re going to kill you before you even wake up in some cases," Malmsten said.

Beckett said the OFAC is pushing for is residential sprinklers. He has sprinklers in his house.

"It’s peace of mind for me," he said. "We’re not opposed to lightweight construction, we’re concerned."