​ The Chimney Clinic

Annex Section A.3.350

Crown

Masonry chimney termination includes considerations of weather protection for the chimney and thermal expansion of the flue liner.

The chimney crown offers the advantages of extension beyond the sides of the chimney to direct water away from both the flue and the chimney. A properly sealed space between the liner and the crown to allow vertical movement of the flue should be design feature of a prefabricated or site constructed masonry or metal crown.

A site applied wash or splay may require frequent mantence to ensure that it remains impervious to water penetration. Because a splay or wash does not extend out past the chimney, which can result in chimney deterioration.

7,2.13.4 - The crown, splay or wash shall be constructed to allow unrestricted vertical movement of the flue lining due to thermal expansion without the introduction or moisture to the chimney.

Napa fire code 211 quick links

cement crown or wash