Q.: Where can we get a deeply colored paint for concrete, one that is highly saturated with primary color? We need it for a multiuse building 600 feet tall. The owner wants several bright colors, not the stains, pastels, and earth tones commonly used on concrete. We're also concerned about resistance to cracking since there will be appreciable movement in a building of this height.

A.: Speaking in generic terms, we think you should use a two-component aliphatic urethane architectural coating. From a comparison of coatings made by James Kubanick several years ago (Concrete Construction, May 1981, page 406) we learned that the aliphatic urethane coatings have excellent color and gloss stability under exterior exposure. They also have excellent solvent resistance, abrasion resistance, and hardness. Yet they are flexible, resist impact damage, and are not subject to long term embrittlement.

The aliphatic urethanes also are available in deep colors. When we spoke with Dave Parish at General Polymers Corporation in Cincinnati, Ohio, one of the manufacturers of this type of coating, he assured us that they could match any color the architect or owner desired. Mr. Parish commented that some acrylic latex coatings would also give good service outdoors, but their color and gloss selections are limited.

Urethanes are sensitive to surface moisture and must be applied to a dry substrate. Carefully follow all the manufacturer's recommendations for safe handling and proper application. Do not deviate from the standard instructions without consulting a technical representative of the producer.