Usually the statute of limitations begins to run when you first discover the problem, but it would be debatable whether or not you actually knew about it before this time. You could contact him and tell him that you just discovered it and ask what did he do, if anything, about it, and why did he or someone write "wet" on the floor and what were his obversations at that time, to get a feel for his intentions. Maybe he did some kind of "band-aid" repair, and it just didn't last. If it's a situation like this, you won't get very far because he'll say he thought he fixed it. You need to check the condition of the wood, and as water seeps can flow anywhere, see if the water went beyond the immediate area.

