The blaze erupted at a two-story, craftsman-style home in the 100 block of S. Ardmore Avenue around 11:45 a.m. and quickly spread to a nearby residence.
A roof on one of the structures collapsed, forcing firefighters to go into defensive mode.
It took 98 firefighters around 49 minutes to knock the fire down. Authorities were investigating a report that an explosion was heard at the fire scene.
No injuries have been reported. The cause of the fire remains under investigation.