Abstract: A method of preserving a building or similar asset (16) from destruction by a bushfire is disclosed. The method includes the step of shortly prior to the arrival of the bushfire at the asset or building (16), spraying the exterior of said asset or building (16) with a water-based fire retardant (17) ejected from a nozzle (10) located above the asset or building (16) and mounted on a helicopter (1) carrying the water-based fire retardant (17).