IRC2018Ch. 10
Chimneys and Fireplaces
Chimney and fireplace construction requirements (R1001-R1006)
Sections
R1001.1
General — Masonry Fireplaces
Masonry fireplaces shall be constructed per this section. Firebrick or equivalent lining required. Clearance to combustibles: 2 inches minimum for masonry fireplace walls, 6 inches from fireplace opening. Chimney must extend at least 3 feet above roof penetration and 2 feet above any structure within 10 feet.
R1003.9
Chimney Flashing
Flashing and counterflashing required at chimney/roof intersection to make it watertight. Corrosion-resistant material. Cricket (saddle) required on the uphill side of chimneys wider than 30 inches perpendicular to the slope.