The fire service and police are investigating the cause of a fire at Parapapaumu School on Sunday evening, which is being treated as suspicious.
Fire crews remain at the scene damping down hot spots on Sunday night and were expected to remain there for some time.
More than 40 firefighters from up and down the Kapiti Coast were called in to deal with the fire at the wooden primary school.
Twelve appliances fought the fire, which destroyed one building containing a library and four classrooms.
Roads around the school were blocked off as firefighters fought the blaze.