Do you keep a litter box in the attic?

We had an issue with my cat, when my wife moved in and brought her 3 cats, and spraying. It was a territory thing, a literal pissing contest, my cat was not pleased. Solution ended up being more litter boxes in more locations (we used to just have one, in the basement that my cat used. We got more and put them on the 1st and second floor).