Hi all, I live in Toronto and I have recently built an outdoor shed ( http://inthebackyard.ca/product-category/sheds/ ). We have built that on uneven ground. We are concerned about whether small animals will use this place as a den. Some critters already got in. But neither the chipmunks nor the squirrels are interested. There are some stray dogs in our locality. But they won't come to our area, hopefully. There are some stray cats to be taken care of. There are chances for snakes to get in also. Currently, there is nothing under the shed but some moss. What's the best way to block off that space and prevent these creatures from getting in?