In building fireplaces, no matter how they are to be finished, it is customary first to build a rough opening in the chimney from 6 to 8 inches wider than the intended width of the finished opening, and an inch or two higher, drawing in the brick above to form the flue. The front wall of the chimney over the opening may be supported by a segment arch when there is sufficient abutment, but when the side walls are but 4 or 8 inches thick, heavy iron bars should be used to support the brickwork. The depth of the rough opening should be at least 12 inches, to permit of an 8-inch flue.
The bottom of the chimney, when there are fireplaces, is usually built hollow to form a receptacle for the ashes from the grate. If the fireplace is to be used frequently an ash pit is almost a necessity, especially in residences, and should always be provided when practicable. When the fireplace is above the ground floor a flue can generally be built to connect the bottom of the fireplace with the ash pit. When there is no furnace flue the ash flue can be carried down at one side of the lower fireplace, thereby saving 4 inches in the thickness of the chimney. One ash flue will answer for several fireplaces. A cast iron door and frame (usually about 10x12 inches) should be built in the bottom of the ash pit to permit of removing the ashes. The ash pit, rough opening and flues form the chimney, and are all built at the same time by the brick mason, who also builds the trimmer arch.
After the house is plastered the finished fireplace is built, usually by the parties furnishing the material, unless it is of brick, when the work may be done by any skilled brick mason. A large number of fireplaces are built with fire brick linings and tile facings and hearths, with wooden mantels. In the past, affluent homes featured large fireplaces with a pair of great brass andirons. Often in the sitting-room, picture tiles were set on each side and over the fireplace. These tiles were square, flat pieces of earthen ware, like a dinner plate. These tiles around the fireplace were all the fashion in the nineteenth century and in some very old houses in Europe they may be seen now. The pictures around the fireplace at times had a story, which were just like a book to young children sitting nearby.
The various steps in building such a fireplace are to first level up for the hearth with brick or concrete, after which the hearth and "under fire" are laid, the metal frame at the edge of the opening set up and the lining and the backing for the tile facing built. After this work is completed the tile facing is set, and when the mortar has dried out, the mantel, if of wood, is set against it. It is best to use glazed tile for the hearth and facings, and they should always be set in cement mortar. The sides of the lining or fire box should be beveled about 3 inches to the foot, and the back should be brought inward at the top so that the opening into the flue will be only about 3 inches wide.