Hi all, I'm planning sectioning off a play area for my kids with a climbing frame and not sure of the best surface for underneath. My first thought was sand (but worried about cats) or bark (but don't want them getting splinters). I was then looking into rubber mulch but it's sooo expensive and it'll be a large area (7m x 6m). Has anyone here made their own rubber mulch with old tires and a chipper? Would you recommend it? What surface would you recommend? Thanks in advance