The main level of a house undergoing construction in Weston collapsed on Friday evening.
The accident occurred at a property along William Street between Merrill Avenue and Pine Street at 7:30 p.m.
The first floor fell into the basement of the house, Toronto fire said.
No one was in the home at the time of the incident and no injuries were reported.
A building inspector has been called in to assist with the investigation.
The cause of the collapse is not yet known.