95% of water leaks are attributed to the flashing. If water passes through the flashing, it can run right down the chimney and onto your ceiling or fireplace facade. Furthermore, most of the flashing we find in the field is not done correctly. Let me explain. The flashing on your chimney needs to be able to move. The roof on your house is going to expand and contract as it heats up and cools down. The masonry chimney is not going to move. Therefore, you need to have a flashing that is going to be step flashed and then counter flashed.