My kitties have been known to crawl into holes in the walls out of curiosity. My worst fear would be having to tear a section of wall down to get one out. I have had to tear down an inner wall in my hen house to remove chicks who found a hole in it and gone exploring. I'd also want to be sure no dead animals like pigeons, bats, or rodent poison was put in there.

Thanks calliope, you made some great points! Right now I have the entrance to the stairs blocked off so he can't get up there but I want to cover the entire top part of the stairs and put the litter at the bottom. Then I could also hang my broom and other stuff there but not allow him up to the attic.

Your covering the stairwell may not be safe from a 'code' point of view and should be checked with your landlord. There could be issues of access in a fire, or ventilation to the attic in summer, etc. Unless you're just sort of blocking the space with stuff that you can remove immediately if necessary, rather than building it in, I'd check it out before doing so (and I wouldn't ever let my cat up there... what if there's a hole he could get out of?).

Do not let your kitty in your attic! I have an old house with a stair case which leads up to an unfinished attic -- very similar to what you have described. My staircase is closed off by a door - so, from the main floor, it looks like a closet in the hallway.

A few times, the door was left open (bringing down Christmas lights...) and the cats went "exploring". I had a heart-attack and a difficult job retrieving them. You know how they can be when they KNOW you want to reach them and they do NOT want to be captured....

I, too, am looking for cheap/creative ways to use that space. I am using it as storage currently, but 'filthy' doesn't even describe the degree of dirt and dust.

I bought cheap plastic 6ft. storage racks from Lowes for items like my tools, xmas things, etc. I wouldn't store anything like clothing there.

If you are able to close off the area with a door, I would do that.