An important component of any chimney system is the top of the chimney. The chimney cap is installed onto the top of the chimney and is vital for preventing water intrusion. The chimney cap also prevents animals from nesting inside the chimney flue. The chase cover, often confused with the chimney cap is different entirely, but many use the two terms interchangeably, adding to the confusion.
A chase cover is used for a pre-fab or factory-built fireplace. Unlike a chimney cap that covers only the top of the flue opening, a chase cover fits over the top of the chimney. They’re also called “top pans” because they top chimneys that are sided with vinyl, metal, or wood. They are a common cause of rust stains on the chimney if installed incorrectly. Ideally the chase cover helps the water to run off completely instead of pooling doing the work of a chimney crown on a masonry chimney. The chimney cap is installed onto the chase cover in the same way as with a chimney crown on a masonry chimney.
Common problems with a chase cover include:
Chimney caps are installed at the top of the chimney and protect the flue against water and wildlife as well as prevent sparks from escaping. On brick chimneys the cap is installed directly onto the chimney crown. The chimney crown is the equivalent to the chase cover. It is a concrete block that prevents water from entering the chimney.
Common problems with a chimney cap include: