DENVER (CBS4) – Fire investigators are trying to figure out what caused a three-alarm fire in Denver.

Flames broke out Saturday evening at a home on East 16 Avenue and Race Street. Witnesses said they could see flames shooting 30 feet into the air and smoke from the fire billowed for hours.

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The owner of the house, Richard, 69, said he was showering when the fire started and almost didn’t make it out.

“I look up after I got out of the shower and I couldn’t believe it,” Richard said. “I just dried myself off in the shower and, ‘My God, this roof is on fire.’ ”

Richard escaped the fire without injuries. He was the only person home at the time.

The fire caused all 18-guests in the Castle Marne Bed and Breakfast next door to evacuate.

Patty Trabing, who lives just behind Richard’s home, saw flames shooting from the roof and went in to help him save what she could.

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“I wanted to help him so bad, but we didn’t have time. I mean the fire was dropping,” Trabing said. “I said, ‘Richard, honey, we’ve got to go, we’ve got to go.’ “

(credit: CBS)

(credit: CBS)

Trabing and other neighbors were grateful to the firefighters’ quick response that kept flames from spreading.

“We thanked as many as we could personally, because it meant everything,” neighbor Louie Feher-Peiker said.

Firefighters said the owner had been using a space heater to keep water pipes from freezing, but didn’t say it was the official cause of the fire.

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Residents in the neighborhood told CBS4 every house on the block is an original structure. Firefighters said the damage to the interior was severe, but the damage to the building’s structure was minor, which will allow for the building to be restored.