Gacodeck is a seamless, synthetic, urethane rubber coating system designed to be applied directly over exterior plywood or concrete decks. It cures in place to provide an attractive elastic covering for surfaces that act as both a floor and a roof. It's an especially popular product for surfaces that are over living space like the hillside house you mentioned in your question. The secret: it doesn't soften under heat or embrittle with cold - it expands and contracts with the surface that it's applied over. A few of the features that make this product popular are that it is lightweight, ski-resistant and tough. It will survive chair legs, foot traffic and roller skates. The manufacturer, Gaco Western Inc., Seattle, Washington, claims that if properly applied and regularly cleaned, Gacodeck will protect a deck for years and years.

For surfaces used primarily for garaging vehicles, Mer-Ko is a good option. Mer-Ko, made by Mer-Kote Products Inc., also is an elastic urethane system, but Mer-Ko is applied in seven layers (Gaco typically is applied in three coats).

By the way, if you're a do-it-yourselfer, Gaco recommends that it's urethane system be applied only by Gaco-approved applicators. The do, however, produce and acrylic-latex system that is available in kit for residential use.

For more information call Gaco Western Inc., at (206) 575-0450.