Masonry Magazine January 1984 Page. 27
The base assembly is corbeled to form the support for the extended hearth.
A soot pocket should be formed at the base of the chimney assembly, approximately 20 in. (500 mm) to 24 in. (600 mm) below the firebox hearth. These dimensions will provide a soot pocket that is approximately 8 in. (200 mm) in height, which will accommodate a standard size clean-out door. The baffle chamber is started at the top of the soot pocket. The baffle chamber should be at least 5 in. (125 mm) (about two courses of standard size brick) high. The last course of brick forming the soot pocket should be corbeled to provide the support for the chimney liner. The first chimney liner should be cut so that the entire front of the liner, for the height of the base baffle chamber, is removed. This opening is used to exhaust the combustion gases to the chimney. The baffle system needs to be designed so that the vertical baffle chamber, at least 3 in. (75 mm) wide and 16 in. (400 mm) long, may be continued up along the sides of the firebox. The remaining portion of the baffle chamber should be constructed so that the combustion gases will be directed to the rear of the