We are finishing out an attic space that adjoins one of the kids' rooms to make it a toy storage and rather sizable play space. It's just rough now with play wood floor. What's the best flooring option? Boys are 1 and 4 so it needs to stand the test of hard play, clean up easily after spilled juice, be kind on little knees, and not be a carpet that little Legos will get lost in. I'm thinking something rubber, like a gym floor but haven't done much research yet.