The cause of Wednesday night’s IHOP fire has fire inspectors scratching their heads.

“Basically the fire started in a void which is a completely empty space,” said Steve Henrichson, St. Joseph Fire Department Inspector. “There’s nothing in the space where this fire started that should have started the fire.”

Fire crews responded to IHOP located at 3804 N Belt Hwy shortly after 9:15 Wednesday.

When crews arrived staff had already evacuated the building.

“The fire itself didn’t take took long to put out,” Henrichson said. “It was chasing the hot spots.”

He said the fire started in the wall in between the bathroom and a mechanical room and then went into the attic.

The building was equipped with a sprinkler system which Henrichson said did help contain the blaze.

“The sprinkler system did its job,” Henrichson said. “It put off enough water that the fire couldn’t spread.”

However, due to the location where the fire started the sprinkler system was not able to put out some of the fire which allowed it to spread into the attic and get into the substructure.

In order to get rid of all the hot spots fire fighters had to attack using another method.

“We don’t normally cut a lot of holes in the roof it was just once it got into the attic it got into the substucture,” Henrichson said. “We ended up having to cut it out.”

Crews had to cut four holes in the roof to get rid of all of the hot spots. He said the scene was not cleared until around 11:30 p.m.

Two inspectors from the St. Joseph Fire Department and an inspector with the State Fire Marshall have investigated the fire and at this point Henrichson said they have ruled it undetermined.

Damages are estimated at $100,000.

Henrichson said the restaurant will most likely be closed for 1 to 2 weeks while crews repair the building.

“Right now there’s nothing else to follow up on,” Henrichson said.