The Royal Collection tiles are made out of extruded polystyrene (a type of styrofoam) which makes them even, thin, and offers a smooth surface, with great natural-looking designs. The unique surface allows the tiles to be able to be cleaned easily, to be water-resistant, and the design allows the customer to give the tiles the finish him/her desire, roller, sprayer, or regular paint brush....since these tiles can be painted with any water-based paint.