The Wall
Foundation walls, technically speaking, are those walls below the grade line of the building that support the super-structure. Similar walls around areas are termed retaining walls and are not properly a part of the foundation. The thickness of foundation, as well as other walls for different structures, is usually established by ordinance in cities and towns; but, where there are no ordinances on the subject, a brick foundation wall of 12 inches, for two-story buildings, or one of 8 inches, for small one-story buildings, conforms to good practice.
The Bond
The foundation wall should be built of a hard-burned common brick, and laid in Common Bond (See [Fig. 47]), with a good cement-lime mortar, starting at the bottom with a header course. As the headers, which serve as transverse bond, are not long enough to extend through the entire thickness of the 12-inch, as they do through the 8-inch wall, the header courses in the 12-inch wall very naturally cannot be on the same level at the front and back of the wall. In the bottom course, the header row is laid inside and the stretcher row outside, while in the next course above the position is reversed, and so on wherever the bonding header courses come.
Laying the Brick
The first course of brick is well bedded in mortar on the footing or the solid ground, as the case may be. At the corners and at proper intervals along the wall where necessary, a few brick, four or five courses high, are laid up in the advance to serve as leads or starting points for the bond and supports for the line which guides the mason to the proper level and alignment of the brick. The mortar is well spread with the trowel along the top of the brick course, and the brick to be laid is firmly pressed down on this mortar bed next the lead. The mortar thus squeezed out of the joint is cut off by the trowel and scraped on the head of the next brick to be laid which is then pressed on the mortar bed and shoved against the brick just laid, so as to squeeze mortar into the bottom of the vertical or head joint which is then thoroughly filled from the top by slushing with mortar. The stretcher courses for structural reasons should be well slushed with mortar between the front and back rows or tiers of brick, laid to break joint.
As the work progresses, the joints on the inside face of the basement wall should be neatly struck, while the outside joints should be cut flush for receiving a waterproof coating. The inside joints are struck by running the point of the trowel, held firmly at an angle, along the upper or lower edge of the brick, thus making a smooth beveled joint (See [Fig. 57]).
The wall should be widened where indicated on any plan to serve as a foundation for the fireplace, and should be built hollow to provide for an ash pit. Where other chimneys occur, the wall at their base should be corbeled out to serve as a support for them.
Scaffolding
After the wall has risen four or five feet, scaffolding is erected to carry on the upper portion. The scaffolding, necessary for the usual house, or other small building, consists of a series of rigid horses or trestles, approximately 5'-0" wide and 5'-0" high, on which are placed a half-dozen 2" × 10" planks laid close. The joists for the floor above may be used for this planking and then lifted into place when the wall is ready to receive them, thus effecting a saving in labor. Care should be taken to keep the horses several inches away from the inside face of the wall, lest the jarring caused by bricks and mortar being deposited on the scaffold may push the green wall out of plumb. The scaffolding for the foundation wall may be dispensed with, if it is found more convenient to lay the upper portion of the wall from the outside.