Crews in Plymouth battled the fire for three hours, the fire and rescue service says.
Devon and Somerset Fire Service says it was called around 21:35 BST to reports of a blaze.
Firefighters tackled the flames in a storage yard during the early hours of Friday.
Inspectors say six recommendations made following a visit in 2024 remain in place.
Parents of pupils who attend The Promise School say the fire will have a devastating affect.
Emergency services say the cause of the blaze is "not thought to be suspicious".
A fire service agrees to rebuild a Plymouth fire station that has "reached the end of its life".
Devon and Somerset Fire and Rescue Service says the fire happened at about 01:25 GMT on Tuesday.
An investigation's under way into what caused a fire at a block of flats in Frome.
