Old timer story alert.
There used to be a lovely service detention barracks in Borden with a central core and five, star-shaped wings. When they concentrated prison services in Edmonton, the Borden barracks became surplus and were, for quite a few years, used as temporary quarters for Militia units and personnel coming up from Toronto and the surrounding areas to do exercises or courses.
I've just did a quick Google maps view of the area and I see it has gone the divestment route. Whenever something requires maintenance but doesn't have a full-time (read RegF) use, it tends to disappear.
What is this school of which you speak?