CHICAGO (CBS) – An off-duty deputy fire chief came to the rescue of an Evanston family last week when he noticed their house was on fire and he ran up to get them out safely.

CBS 2’s Vince Gerasole reports the Wall family was expressing their gratitude after Evanston Fire Division Chief Geoff Block helped save their lives and keep their home from burning to the ground.

“Thank you very much. You saved our lives,” Doniece Wall said as Block and a group of Evanston firefighters visited her home on Wednesday.

“I was in the right place at the right time,” Block said.

“You have no idea,” Wall told him.

Block explained that he was driving by the house last week, taking a route he normally didn’t drive, when he spotted the flames on the roof of the Walls’ home.

“The people across the street over here on this side did not even see it,” Block said. “I didn’t notice it at first.”

But he soon noticed that the roof of the three-story home was engulfed in flames.

“I didn’t see any workers, or any people out around the house. I heard on the radio It wasn’t reported yet, so I knew it was an unreported fire at that point,” Block said.

He called in the fire, then quickly rushed inside to alert the Wall family, who had no idea their home was going up in flames.

“He was yelling at me ‘Get out of the house!’” Wall said. “I’m like ‘What?’”

Block said, “I got about 10 feet into the house, and I was waiting for a big dog to come around the corner, thinking I was a burglar.”

On Wednesday, Wall told Block, “If you had not been there at the moment that you were, we would have not known at all.”

“I think the homeowners were kind of shocked. I think they were looking at me like, ‘Who is this person?’” Block said.

Wall acknowledged that, at the moment Block showed up, she didn’t believe him about the fire.

Firefighters arrived in less than three minutes, containing damage to just the top floors, all thanks to a fire chief who stayed alert even on his down time.

“Right place at the right time,” Block said. “All the pieces fell into place.”

“God sent you here,” Wall said. “You happened to spot it. I mean, who looks at roofs, except for maybe firemen?”

No home alarms were going off, because smoke from the attic fire was rising away from the house. Evanston fire crews estimated that, in another five minutes, the clapboard house would have been fully engulfed.

Block even rushed back inside at one point, to wake the Walls’ son, who was napping in the basement.

Firefighters said the blaze was caused by a faulty fan.