The right concrete floor coating, correctly applied, can change a perpetual source of problems into a smooth, trouble-free "highway" for all foot and wheeled traffic in a building. While a good cure is the best hardener on the market, building owners sometimes find the job they expected is not what they get. For use in these cases, several types of hardening agents are available. They include mainly sodium silicate and magnesium and/or zinc fluosilicate hardeners. Concrete floor sealers and finishes are effective and generally the most economical in controlling problems. They eliminate dust by filling the pores and locking dust in the concrete. When selecting a protective coating for concrete floors, one must take into consideration the standard of maintenance required. Does the owner want a nearly germ-free surface or just regular removal of the major debris- or something in between? What type of traffic is the floor subjected to: foot, wheeled, little, much, heavy or light loads? Application requirements may affect the choice. Find out what is involved and how long the floor will be tied up. Can the owner live with the answers? Available sealers include: chlorinated rubber, oleoresins, one component epoxy esters, oil-modified urethanes and acrylic resins. Chlorinated rubber and oleoresins wear poorly, darken with time and collect dirt. One component epoxy esters, oil-modified urethanes and acrylic resins. Chlorinated rubber an oleoresins wear poorly, darken with time and collect dirt. One-component epoxy esters and oil-modified urethanes wear well, yellow with age and collect dirt to a moderate degree. Acrylic resin sealers provide good wear, light color and only moderate dirt collection.