The act of permanently sealing a chimney involves methods to completely obstruct its flue, preventing airflow and any further use. This is a more involved process than simply capping the chimney opening and generally requires structural modifications. An example would be filling the entire flue with a non-combustible material, such as concrete or expanding foam, after ensuring proper ventilation to prevent moisture buildup in the remaining structure.
Completely sealing a chimney offers benefits that include improved energy efficiency by eliminating drafts, preventing pests from entering the home, and mitigating potential structural damage caused by water infiltration. Historically, this was often done when heating systems were upgraded to models that did not require a chimney, rendering the existing structure obsolete and a potential source of heat loss. The practice contributes to a more sustainable home by reducing energy consumption.