It’s decorative and functional trim ... Polystyrene (trademarked as Styrofoam) is the most lightweight crown molding material and can be used indoors or outdoors. Installation is easy.
DIYer Concocts Renter-friendly Way to Install LED Crown Molding Crown molding is essentially a decorative trim, usually made of wood, plaster, rubber, peel and stick, Styrofoam, or similar substances ...