Multi-flue chimney caps are designed to cover more then one masonry flue. Unlike normal chimney caps, multi-flue chimney caps typically are anchor bolted into the chimney crown with tapcon bolts and even glued to the crown for added strength. Most of these caps have wing nuts that can be removed from the top and the entire top of the chimney cap can be removed to allow for cleaning. There are standard sizes to multi-flue chimney caps and there are custom sizes. These chimney caps are sized to be placed in the space located on the sides of the flue tile and the edge of the crown. Attention should be paid to make sure the chimney cap lid is not sitting directly on top of the flue tile. This will block smoke passage and prevent the chimney from drafting. Usually, 4-6 inches is enough clearance to allow for the smoke to escape the flue.