Fire crews were called to reports of a chimney collapse in Caunce Street, Blackpool, at 6.45pm on Monday.
When they got there, officers found the structure had collapsed into the roof space, and ordered the occupants to evacuate.
A spokesman for Lancashire Fire and Rescue Service said: “We think the damage was done during Storm Doris last week.
“The chimney material was contained within the roof space and nobody was hurt, but we made sure the scene was safe and recommended the council’s building control department was notified.”
No other buildings were affected.