Unconfirmed reports claimed pupils had set fire to the hall in protest against writing exams.
Local councillor Sarah Wissler shared on her Facebook page that the pupils are in grade 10.
Gauteng education MEC Panyaza Lesufi, who on Tuesday visited the school to assess the damage, shared a photograph showing pupils writing the exam outside.
“Yesterday they burnt the school hall because they didn’t want to write an exam. Today they wrote the exam outside. So sad,” he tweeted.