Balfron High School pupils are going to be bussed to other schools across Stirlingshire while essential building repairs are being carried out.
Stirling Council partially shut the school during the first week in May after finding a problem with the wall at the stairwell and additional issues in the atrium.
Council education chiefs say the new problems with the building - which was built under a Private Finance Contract 15 years ago - were not immediately obvious during previous checks.
S1 to S3 pupils were initially told to stay at home and then from Friday, May 13, they will be bussed to St Modan’s, Wallace High and Stirling High for classes until the repairs are done.
The council is also looking at the possibility of building temporary accommodation at the school.
SQA exams went ahead as planned, with senior pupils being directed to allocated rooms in the school when they arrived. There were also areas set aside for studying before or after exams.
The council says disruption is being kept to a minimum and work will not take place while exams are being held.
In April safety concerns closed 17 schools in Edinburgh which were built as part of a public private partneership ten years ago.
Two issues were discovered at Balfron, which is owned by Balfron Schools Ltd, by independent contractors including ‘suspicious wall movement’ at a stairwell and a minor issue with a wall in the gym hall.