Photo via U.S. Navy  Mass Communication Specialist 1st Class James E. Foehl [Public domain], via Wikimedia Commons
Photo via U.S. Navy Mass Communication Specialist 1st Class James E. Foehl [Public domain], via Wikimedia Commons

A fire apparently caused by spontaneous combustion caused an estimated $25,000 worth of damage Thursday to a granny flat undergoing renovation behind a North Park house.

The non-injury blaze in the 3100 block of Granada Avenue erupted shortly before 11 a.m., according to the San Diego Fire-Rescue Department.

It took crews just under 20 minutes to control the flames, which damaged one exterior wall of the unoccupied and unfurnished cottage along with its attic and roof, SDFRD spokesman Lee Swanson said.

Investigators determined that the source of the fire likely was some sort of unstable substance, such as linseed oil, that heated up due to a chemical reaction and set fire to construction materials stacked up against the structure, he said.

— City News Service