Barrie firefighters don’t know what caused a house fire on Henry Street Friday.

Four firefighters had minor injuries from fighting the blaze, with two going to Royal Victoria Hospital.

Smoke from the burning home at 74 Henry St. could be seen from Highway 400 and attracted a few spectators to the scene. No one was home at the time of the fire, which was reported at 4:20 p.m.

Police arrived and evacuated neighbouring homes for safety reasons.

Just before 5:30 p.m. Friday night, firefighters were told to get out of the building so the back windows of the home could be smashed. After that, crews began spraying water on the home from all directions – including an aerial ladder.

Deputy Fire Chief Rick Monkman said it was a stubborn fire.

“Even at 7 a.m. the next morning, we had numerous flare ups,” said Monkman. “We had crews there up until noon on Saturday.”

The problem was many additions to the home through the years had left small spaces to contain a fire.

“It was difficult to get in there and it wasn’t safe to send crews in there, so we had to wait for the fire to come to us.”

Using a thermal imaging camera didn’t help pick up all the hot spots between floors or in a void, he said. “You won’t pick it up until it starts intensifying in growth.”

Monkman said the damage is estimated at $300,000 and the Fire Marshal’s Office is still investigating.

He said the homeowners were painting and doing some renovations before the fire.

 jramsay@simcoe.com