SAN FRANCISCo (CBS SF) — A Wednesday night fire heavily damaged a vacant San Francisco home and then spread to a neighboring home in the Mission District before it was brought under control, authorities said.

San Francisco Fire PIO Jonathan Baxter said the first call came in at 6:31 p.m. reporting the blaze in a two-story vacant residential building at 1007 Shotwell Ave.

Arriving firefighters discovered the fire had spread to the residential building next door and called in a second alarm.

The blaze was brought under control in less than an hour but not before it had displaced 11 people.

There were no injuries and the fire remained under investigation.