How many inches should flue liners project above the crown?

Flue liners are essential components in chimneys, serving to protect the chimney walls from heat and corrosion while ensuring the safe venting of combustion gases. The standard requirement for the projection of flue liners above the crown is four inches.

This height ensures that the liner is adequately exposed above the chimney crown, minimizing the potential for water intrusion and allowing for effective smoke and gas venting. A projection of four inches helps to prevent moisture from pooling around the top of the liner, which can lead to deterioration and other related issues. By maintaining this standard height, the overall integrity and safety of the chimney system are upheld, contributing to its efficient operation and longevity.