Replace the chimney cap when it begins to rust or corrode. The continuous exposure to moisture, creosote, and other contaminants can result in rust or corrosion and weaken its effectiveness. When the chimney cap is heavily rusted, it can easily rip apart.
A chimney cap is designed to protect top of a chimney and are made of masonry or metal. They help prevent rain, snow, debris, animals, and birds from entering the chimney. Screen and spark arrestors are often a part of a chimney cap/cover to prevent the emission of sparks and animal or bird entry.Chimney caps can prevent rust and deterioration of the flue system and firebox due to moisture. Premature deterioration of the firebox and liner mortar joints in a masonry fireplace is usually a result of water entry. Future damage may be prevented by the installation of a chimney cap. There caps of a specialized design that may also assist with downdraft problems.