Quote Originally Posted by CO Hugh View Post
While you say its the toliet, in a bathroom that was infrequently used, the plumbers putty around the drains or fixtures can dry out and leak when used. If so that is easy to fix.
^^^^^^^^^^^^^^^^^^^^ This is most likely the problem. Check the tub drain for dried putty and pull the toilet to check the wax ring. While it's up put in an extra thick wax ring.