A burst water pipe caused a school staff room ceiling to collapse resulting in flooded classrooms.
Pupils' work was damaged in the incident at Bourton-on-the-Water Primary School.
Headteacher John Jones said he told the 237 pupils to stay at home because of the flooding, which he estimated had caused £15,000 of damage.
"I drove along the treacherous roads, and got in to find all the fire alarms were going off," he said.
"After turning them off we were met by water pouring through a 6ft (1.8m) by 5ft (1.5m) hole in the staff room ceiling. My main fear was that the electrics were in there."
"The saddest loss is the classroom - all the children's work has been damaged."
The school was one of 17 in the county to close on Monday.
Water company, Severn Trent, reported a 50% increase in calls, mainly from homes and businesses with frozen pipes.