air sealing
 

Would the PL-300 be ok to seal the seams and at the concrete floor with xps? Do I really need to get spray foam in a can for this? Tyvek tape will go over it. I just don't 100% trust the tape to last for years in all it's stickiness.

Anyone know? I don't trust that Great Stuff as I have not read that it's compatible with xps board and don't want it damaging it. The gap at the bottom and the concrete floor is very minimal. Would that PL-300 work for a proper seal?

Yes, the foamboard has been known to shrink over time, loosening tape and breaking adhesive bonds. I'd use canned foam, personally; http://www.buildingscience.com/docum...a-foam-shrinks

Gary