I'm sure different people will get all sorts of various ideas about how to "finish" it back there.. I am just gonna leave mine just the way that it is. That works fine for me. Consider that fiberboard will be hard and slippery if you ever want to put something on it- unless you put the rough side of the board facing outside.. Then it would just be hard n flat. I like that mine has a soft foamy surface that will be more accomodating to various things if I did ever have to put something on top of those, but I would definitely just put the seat bottoms up and use the floor in that situation.