Yes, the openings between the roof & frame b/c the roof zig-zags. That's what I am planning on using the foam for. Wood won't even fit, the roof is right on the wood, but the snake idea really creeps me out, so I want to block them. Only snake I've ever seen in my yard is a black racer. My neighbors swears there are black moccasins in the creek that runs along the back of my property.