Crews were called to a home under renovation on Hampshire Grove NW around 12:45 p.m. When firefighters arrived, they found thick, dark smoke and flames coming from the roof. “At one point in the firefighting efforts, fire crews exited the structure for their own safety and fought the fire defensively due to an imminent roof collapse,” the Calgary Fire Department said in a news release Thursday. Once the flames were under control, firefighters returned to the interior and completed their search of the structure. The house was severely damaged largely due to the collapse of the roof on the second floor. Officials say two residents and two workers who were in the home when the fire broke out made it out safely and no injuries were reported. A fire investigator is working to determine what caused the fire. The Calgary Fire Department is asking anyone with video or photos of the fire — especially before crews arrived — to email them at [email protected]