Rob,
I agree with Roger, Great Stuff is extremely sticky and has great bonding  
properties. After gluing it back in place, I would then encase it in fiberglass, 
 but may sure the great stuff has had sufficient time to cure. It expands at 
a  tremendous rate for about thirty minutes. Once dried, any amount that needs 
to  be removed can be cut with a serrated kitchen knife.
 
Rummy