The Park City Fire District responded to the fire at the unoccupied house near Little Kate Road and Lucky John Drive around 5:30 a.m. Thursday.
Chief Bob Zanetti told KPCW the second floor collapsed as firefighters tried to get into the home.
“The second floor has collapsed down now. So we weren't able to get crews, on our initial attack we went in, but backed out almost immediately, because the whole upstairs is pretty much on fire,” he said.
No injuries have been reported as of Thursday afternoon.
Zanetti said the home was unfinished, and may have been under construction for years.
Four engines, one truck, 20 firefighters and emergency medical services responded at the fire’s peak, the chief said.
Portions of Park City Transit's 2 Green and 3 Blue bus lines were detoured until about noon.
The cause of the first remains under investigation.
