You know, another 4x4 or 4x6 positioned in between the other two skids would be a perfect additional support. It doesn’t need to be notched to fit the floor joists, rather butted right up against them with cap blocks and shims. Perfect support.Here are pictures of the underneath. I'm not sure why it's built with 2x4'sView attachment 2511475View attachment 2511476View attachment 2511477