Expanded plastics are a new material that is useful in the restoration of paintings. They are available in preformed sheets or foam-in-place liquids. The semifinished plastics are polystyrene, polyurethane (rigid, semirigid, flexible) and poly (vinyl chloride). Foam-in-place plastics, which are usually polyurethanes, are resin/ catalyst, prepolymerized or one-shot systems. Information on color, solvent resistance, uv resistance, flammability, etc. Of each type is given. Also included is a discussion of remounting detached frescoes on to rigid or sandwich panels. A list of commercial products, chemical type and supplier, is appended.