Elaine I was think about putting a sand box in also I have kids 13 years old playing in it. But mine is to small so I'm making a bigger one. I'm digging my grass up about as big as a sheet of plywood and use treated wood with coner brakets then use the out door carpet on the top of the wood just so if the kids walk the wood they fall off the side they won't get hurt that bad. On the bottom I'm using Weed block it's a lite weight plastic with real small holes in it so water can drain out just in case you leave the lid off. And when your kids are done with it the sand can go in the grass and you can replant that area no space lost.