During the 12 years I've been repairing chimneys, I've found that most chimney problems can be traced to a handful of causes. In this article, I'll identify the problems I most often encounter, and explain the techniques I use to repair them. Up-Close Inspection Typically, the exterior of a chimney will deteriorate first. A few minutes spent inspecting a chimney will often reveal telltale signs of problems. I start at the top, and check to see that the crown is sound and free of cracks. Next, I examine the joints, looking for any missing mortar, hairline cracks, or soft, eroded mortar. I also check the integrity of the mortar bonding by tapping the bricks or blocks with a hammer. A