But there is no uncertainty on one point. Far fewer children will get "wet, high and upset" moving from one class to another. Drew Grieve, the council's project manager, says the old school was "by far the worst in our authority".
Rusty and damaged, with 24 classes in huts, and a variety of "interesting internal struts to stop the roof falling in", Balfron High was a good school in a terrible building.
What the new school will look like when it is a comparable age, or even by the end of the 25-year contract Stirling and Jarvis plc have signed, remains to be seen. But members of the Scottish Schools PPP Group, drawn from authorities around the country, declared it impressive last week during a site visit.
Balfron has had its share of problems, however, over hidden costs. There has also been a breakdown in relations with Balfron community council over disposal of the old school, sold to Jarvis and scheduled to make way for new houses. But the facilities the new school can offer - the whole building will be available for lifelong learning - should help heal the wounds.
Teaching staff have been closely involved at all stages, Sandy Kelso, deputy head, says. His full-time secondment to the project ends with the start of the new term.
This has helped make Balfron High one of the first buildings in the country designed to run a modern curriculum, and flexible enough to cope with the inevitable changes. While Mr Kelso has reservations about other aspects of the project such as the cost - "around pound;50 million for a pound;15 million building" - he is clearly excited.
Gordon Jeyes, Stirling's director of children's services, says the trick has been building a school today for tomorrow's needs. "It seems clear you will want to adapt the curriculum to individual children, to bring different types of learning together, greater ranges of learning and new technologies," Mr Jeyes said.
"Subject dominance will begin to decline as youngsters get cognate information using Internet-based courses, and initiatives can be taken forward by pupils and groups across the subjects.
"The balance of use between teenagers and the rest of the community may alter and the way in which education is organised for the secondary stage could see massive change. It's not just a collection of classrooms."
Leader, page 12