This is a great enclosure, I purchased two. There is no bottom in this kennel other then the tray that comes with it. The tray is functional and I use it, but you wouldn't have to. It just lays inside the crate once it is fully installed and there is a small gap between the bottom tray and the edge of the kennel. No problem for me, but not good for small newborn puppies. I though maybe someday I would have a piece of plywood cut and replace the tray with that. But for now it works great for my German Shepherds. The crate itself is awesome. Easy to put together and easy to pull it apart when needed. My dogs love it too! I bought a washable bath rug the same dimensions as the crate and put that in it for comfort.