I was concerned that Rosie, my iRobot Roomba, might not be able to maneuver over the threshold between the ceramic tile & wood floor, from the floor to the rug, or even over some of the uneven tiles. But I NEVER thought it would be able to do this! That cat tree platform is 1" tall! I've even seen it vacuum around each of the four posts, then exit out the other side. It EVEN tries to climb up on the bowflex platform! Determined little sucker. Pun intended!