Hi Brad,
Thank you for your question. Roppe doesn't manufacturer inside corners. We suggest that our customers mitre cut the inside corners. Also, you may want to look at another one of our products. It is exclusively designed for Gym floors. Please copy and paste this link to view our Vent Cove Base, http://kofflersales.com/p/johnsonite-vent-cove-base.asp?cid=58
Thank you,
The Koffler Team