American Hydrotech, Chicago, offers Hydroguard® RE, a lightweight self-ballasted insulation board designed to top off protective membrane roofs. The panels provide thermal protection and integral lightweight ballasting to protect a roof's waterproofing membrane from mechanical abuse and the elements, while also providing a highly reflective roof surface. The 2- by 4-foot panels are easy to install and are ideal for flat roof applications where the use of stone ballast is not practical because of its weight. The board is composed of a Styrofoam® extruded polystyrene foam insulation board topped with a light-colored 3/8- or 15/16-inch latex modified concrete mortar surface. Each panel has tongue-and-groove edges along the long sides that allow each board to be interlocked during installation, creating a continuous layer of thermal protection. In addition to the highly reflective surface, the panels are also available in a variety of colors.