Officials tell Action News it happened just before 10:00 a.m. Tuesday in the 5200 block of North Marshall St.
Arriving firefighters found a rear section of 5217 N. Marshall St. had collapsed.
No one was injured. But officials have evacuated the occupants of the damaged structure and two adjoining row houses as a precaution.
Philadelphia Licenses and Inspections is assessing the stability of the properties.
