In building a successful fireplace, there are at least six things that must receive attention. They are the flue or chimney, smoke chamber, throat, firebox, hearth, and mantel. Of the six, the least important, from the standpoint of construction, are the outer hearth and mantel. To be sure, they are the parts that give the fireplace a decorative effect; but they are not essential to the operating efficiency of the installation.
After the selection of the design for the mantel, the next important step is to determine the size. Too small an opening restricts the amount of heat thrown into the room. The average fireplace is from 30 to 40 inches in width between the jambs. The height of the fireplace and the depth of the fireplace from front to back do not vary to the same extent as the width of the fireplace. The table on page 44 will show you the proper proportions.
The shape of the firebox is important. Its sides should be splayed, that is, drawn in toward the back at an angle of about 15 degrees with the front, or about three inches for every foot. The back of the fireplace should be vertical for a distance of approximately ten inches; then drawn forward to a point where the damper rests upon the masonry. This arrangement provides for throwing more heat into the room.
The ash dump should be placed directly below the fire or the inner hearth so the ashes may be worked through it to the ashpit below. A door to the ashpit at the level of the basement floor will make it easy to remove the ashes.
