A fire that did significant damage to a home under-construction in Casper Sunday night remains under investigation.

According to Casper Fire EMS spokesperson, Captain Pat McJunkin, a cause for the fire has not yet been determined.  "At this point investigators have taken a look at it, but they haven't been able to determine an exact cause at this point."

McJunkin says crews responded to the fire in an unoccupied home near Paradise Valley just after 11:30 Sunday night.

Heavy fire was reported in the home's crawlspace area, weakening the floor of the home, causing fire crews to fight the blaze from the exterior of the home.

"The floor began to sag, and there some concern of the significant collapse and an issue of safety to fire fighters," says McJunkin.  "There was not a complete collapse, but a partial collapse in the rear of the building."

Investigators say the home sustained major fire and smoke damage.

A fire that did significant damage to a home under-construction in Casper Sunday night remains under investigation.

According to Casper Fire EMS spokesperson, Captain Pat McJunkin, a cause for the fire has not yet been determined.