Decorative Styrofoam Celing Tiles are 20x20 inches, easy to install, paintable and can be glued over popcorn ceilings, drywall, plywood, sheetrock, stucco, knock-down, etc. These tiles can be also easily painted with any water-based paints, metallic or non-metallic. Depending on the finish you can achieve plaster or real tin look for less and fast.