Firefighters were called to the 700 block of East Palm Avenue at 2:12 p.m. by a neighbor who reported the blaze, said Burbank Fire Capt. Peter Hendrickson.
FOR THE RECORD: An earlier version of this story stated the fire occurred on Tuesday. It occurred on Wednesday.
When authorities arrived, the attic was fully engulfed in flames. Shortly after, the blaze burned through the roof and caused it to collapse into the structure, he added.
All three residential units were affected. Surrounding buildings were not threatened by the fire, Hendrickson said just before 4 p.m. At that time, roughly 50 firefighters were still battling the blaze.
“It’s not going anywhere out of the structure,” he said.
No injuries were reported. The cause of the fire was not immediately known.
Reporter Veronica Rocha contributed to this report.