Firefighters from 3 agencies fight fire at under-construction Bonsall home

North County Fire Protection District responded to the scene of a structure fire located in the 4200 block of Paso Del Lagos in Bonsall Thursday night.

The call first came in at 10:42 p.m. North County Fire Protection District spokesman Capt. John Choi said.

Firefighters arrived to the location to find the house, which was under construction fully involved, Choi said.

The homeowners and their two dogs were accounted for.

Choi said that the department faced some unique challenges fighting the blaze.

"We had a couple of significant challenges on this house fire that created," he said, adding that the fire had spread into the attic. "So it was across the entire attic, was burning across the joists and the rafters which made the area unstable."

Choi said the fact that the roof was metal also created issues for firefighters.

"If it's a metal roof there is no cutting oval in it to make entry, there is no going on the roof and there is no operation that will penetrate the roof," he said. "The conditions of the fire made it very unstable for crews to go inside.

"We determined the safest way to attack this fire was from a defensive posture. Fighting the fire from the outside of the structure" Choi said.

"The best strategy was to perform a controlled burn down of the structure and to protect the exposures. It was unsafe to enter due to the fire damage of the unprotected and exposed wood; the fire had spread throughout the house; and the attic space was compromised with that metal roof. All that made it unsafe to extinguish from the interior and we had to extinguish from the exterior," he said.

"We did a full burn down of the structure so that way the roof would collapse inward and give us access to all the hidden spaces of the fire," Choi said. "Otherwise we wouldn't have been able to fully extinguish this fire."

Firefighters also kept the structure fire from spreading to nearby vegetation.

In all, three NCFPD engines, the NCFPD Battalion Chief, the NCFPD Fire Marshall, the NCFPD Fire Chief, one Vista Fire Department Engine and Rescue Ambulance, two Oceanside Fire Department engines, and a Light and Air unit from San Diego City Fire Department were all on scene.

The Light and Air unit was there to provide lights to the scene and to also replenish air tanks that fire crews had to wear.

Choi explained that material used in building are highly toxic as they burn, so even though fire fighters did not enter the structure, the fumes from burning materials was toxic, so they all wore masks and tanks.

Fire crews will take turns throughout the day watching the fire and knocking down any hot spots, Choi said.

"It will be a physically intensive day of pulling and moving the debris around and watering it down," the spokesman said.

Cause of the fire is under investigation.