A fire caused extensive damage to Niagara-on-the-Lake home on Tuesday.

The fire started around 4 p.m. and spread from a neighbouring shed to a newly built home on Simcoe Street near William.

NOTL fire chief Nick Ruller said the damage is estimated at about $1.5 million.

Because the damage is so extensive the Ontario fire marshal is investigating and was on scene Wednesday, Ruller said.

No official cause has been determined yet, but the investigation is focused on the neighbour's shed as the area of origin, he said. A bus in the neighbouring driveway was destroyed in the fire.

Maddie Mulligan, who lives across the street, was outside with a technician from Bell when the blaze started.

“We saw a shed on fire and then we heard a big bang. It was so loud,” Mulligan said.

“We looked outside and it was this billowing smoke coming out, and then we started seeing the bus on fire. Then it went onto the side of the fence and that’s when the whole side of the other house went off.”

As the fire started to consume the bus Mulligan began to get worried.

“We thought that something was going to explode, like if the bus had gasoline in it,” she said.

“What a loss and what a shame. That house just went up. It’s gorgeous,” said Mulligan.

Russel Levrov, the Bell technician working at Mulligan's house, said he was the first to call 911.

Ruller said crews from all NOTL stations were called in to assist with the blaze.

He said there was “significant fire involvement into the attic” of the home.