Painting or powder coating of steel with epoxy, urethane, or alkyds initially provides a barrier protection system. However, these coatings are easily damaged during installation and must be properly touched up and repaired if they are to be as durable as warranted. Most paints and powders are porous or are easily damaged, allowing electrolytes (moisture, humidity) to reach the underlying steel. If regular maintenance is not performed, underfilm corrosion begins and the coating will fail in a relatively short period of time. There is no cathodic protection provided by paints and powder coatings, thus limiting their durability to ten years or less in most environments.