Q.: Random horizontal and vertical cracks showed up on about one-third of the panels of a large tilt-up warehouse when they were given a medium sandblast finish. These don't go through the wall and aren't a problem structurally but they look bad. Can they be repaired by epoxy injection or other method so they won't be seen? We prefer not to coat the panels because it would be very expensive.

A.: Unfortunately nonstructural cracks that might otherwise never be noticed are often revealed by sandblasting. Also unfortunately, repair of the cracks by epoxy injection or other method is likely to make them more conspicuous rather than less. The only method we know for obscuring them is to cover them by means of some coating or plaster which provides a surface that is not smooth. A textured coating might be the least expensive solution, though undoubtedly more costly than you had hoped.