What should openings around chimney flues and other air passages be to meet local codes?

Openings around chimney flues and other air passages should be closed or sealed using sealant or fire-resistant materials approved in local codes for such applications to ensure safety and compliance with building regulations. This sealing is crucial because it helps to prevent the entry of harmful gases, such as carbon monoxide, from appliances or flues back into the living space. Additionally, sealing these openings minimizes air leakage, improving energy efficiency and maintaining indoor air quality.

Using fire-resistant materials is particularly important as it provides an added safety measure to prevent the risk of fire spreading through these openings. Local codes are established to ensure that structures maintain a high standard of safety and health, and therefore, compliance with these codes is essential when sealing around flues and air passages.