Over time, even the interior portion of a chimney may start to deteriorate. This is especially common in homes over one hundred years old. Parging over old exposed sections of a chimney will help maintain its structural integrity. Parging involves applying a thin layer of fiberglass reinforced mortar to the surface of the chimney, effectively sealing and reinforcing it. Additionally, parging can improve the chimneys appearance, making it more aesthetically pleasing while ensuring it remains safe and functional.