Do they need to be removed during the winter? Can they withstand snow & ice? Could they be installed over tamped sand or does it need to be gravel?

Our Outdoor Sports Tiles are made from a hard plastic polypropylene and can withstand the elements without being damaged, so there is no need to remove them for the winter. They will be able to withstand the ice and snow. We do recommend placing our Outdoor Sports Tiles over a hard flat surface like concrete or asphalt, but customers have installed these tiles over grass, sand, and crushed gravel with success.