Mud Hearth
Here you see there is a mud hearth, a wall of clay plastered over the stones of the fireplace. This will prevent the fire from cracking and chipping the stones, but clay is not absolutely necessary in this fireplace. When, however, you build the walls of your fireplace of logs and your chimney of sticks the clay is necessary to prevent the fire from igniting the woodwork and consuming it. For a log-framed fireplace, make a large opening in the wall of your house and against the ends of the logs where you sawed out the opening, erect jamb pieces of planks two or three inches thick running up to the log over the fireplace and spiked to the round ends of the logs (see plan, [Fig. 272]). Next, lay your foundation of sill logs on the fireplace, first two side logs and then a back log, neatly notched so as to look like the logs in the walls of the cabin. Build your fireplace walls as shown by [Fig. 271], after which take your mud or clay and make the hearth by hammering the clay down hard until you have a firm, smooth foundation. The front hearth may be made, as shown in the diagram, of stones of any size from pebbles to flagstones, with the surfaces levelled by sinking the under-part down into the clay until a uniform level is reached on top. The fireplace may be built with bricks of moist clay and wet clay used for mortar. Make the clay walls of the fireplace at least one foot thick and pack it down hard and tight as you build it. If you choose you may make a temporary inside wall of plank as they do when they make cement walls, and then between the temporary board wall and the logs put in your moist clay and ram it down hard until the top of the fireplace is reached, after which the boards may be removed and the inside of the fireplace smoothed off by wiping it with a wet cloth.
Stick Chimney
After the walls of logs and clay are built to top of the fireplace proper, split some sticks and make them about one inch wide by one and one half inch thick, or use the round sticks in the form in which they grow, but peel off the bark to render them less combustible; then lay them up as shown by [Fig. 261], log-cabin style. With the chimney we have four sides to the wall in place of three sides as in the fireplace. The logs of the fireplace, where they run next to the cabin, may have to be chinked up so as to keep them level, but the chimney should be built level as it has four sides to balance it. Leave a space between the chimney and the outside wall and plaster the sticks thickly with clay upon the outside and much thicker with clay upon the inside, as shown by [Fig. 271] A, which is supposed to be a section of the chimney.
[Fig. 269.] [Fig. 270.] [Fig. 271.] [Fig. 272.] [Fig. 273.]
Detail for fireplaces and flues.
Durability
All through the mountains of East Tennessee and Kentucky I have seen these stick chimneys, some of them many, many years old. In these mountain countries the fireplaces are lined with stones, but in Illinois, in the olden times, stones were scarce and mud was plenty and the fireplaces were made like those just described and illustrated by [Fig. 272.]