The following data have been compiled and the drawings made by Mr.
George W. Repp, a Chicago architect, and are based on the most
widely followed building practice.
There is no intention of trying to inform the master mason or
the master carpenter about his craft with which he is perfectly
familiar, but to show the master carpenter builder the best methods
of handling the brick problems that may confront him in solid
brick, hollow tile, and veneer wall construction. A glossary of
technical terms will be found at the close of this volume.
[Sidenote: Footings]
Whatever type of construction is chosen, solid brick, hollow
tile, or veneer, it should rest upon a solid brick foundation.
In the majority of cases, where soil conditions are favorable,
the brick foundation walls of moderate sized houses do not need a
footing except at points bearing concentrated loads. Naturally,
the excavation should be carried down to good solid earth, free
from loose, spongy soil or filled-in ground which might later
permit sufficient unequal settlement to result in serious cracks
throughout the wall of the house. Where conditions seem to require
a footing, it may be either of brick laid in good cement mortar
(Fig. 1) or of concrete as shown in our working drawings, and
should be strengthened at points of special bearing stress. Which
footing is chosen will depend largely on convenience of getting
local material and labor. The bottom of the foundation wall or
footing must always be below frost line which, of course, varies in
different sections of the country; and this rule applies as well to
all brickwork outside of the foundation wall proper.
[Illustration: Fig. 1. Brick Footing]
[Sidenote: Drains or Drainage]
Where the conditions of soil require, porous tile with open joints
should be laid around the base of the foundation wall, not above
the level of the basement floor nor below the bottom of the wall or
footing, and slightly pitched to a point where it may be connected
with the sewer or some natural outlet. Where this tile is laid in
loose sandy Soil, the open joints should be wrapped with building
paper to prevent the sand from clogging the drain. In heavy clay
soil, the tile should be covered to the depth of about a foot with
crushed stone to prevent packing of clay around the tile.
[Sidenote: 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.
[Sidenote: 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.
[Sidenote: 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.
[Sidenote: 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.
[Sidenote: Waterproofing]
All brick foundation walls should be water-proofed on the outside
except in gravelly, sandy, or very dry soil. In case there is
danger of moisture rising in the wall by capillary attraction, the
top of the footing should be water-proofed, before starting the
walls, by a course of slate well bedded in mortar or by a strip of
composition roofing. In wet locations, it would be well to carry
the waterproofing under the basement floor also. For waterproofing
the foundation walls, in slightly wet soils where the drainage is
fair, a coating of one-half inch cement plaster may be applied to
the outside surface of the brick as the wall is carried up. This
plaster should be composed of one part Portland cement and two
parts clean, sharp sand. The possibility of settlement cracking
this cement coating makes it undesirable for use in heavy soils
such as wet clay, or in low-lying land where the subsoil is likely
to be wet. In such conditions, a coating of asphalt applied
while boiling hot, thoroughly covering the brickwork, is very
satisfactory. A less expensive though excellent waterproofing,
which we suggest in our specifications, is made of three parts
of tar and one of pitch. Tar alone is sometimes used, but is not
recommended as it becomes brittle and is subject to cracks, similar
to cement. Except in dry, warm weather, it is well to prepare
the wall for the waterproofing by sizing or priming it with hot
creosote, to overcome any dampness that might prevent the asphalt
or tar-pitch from taking proper hold.
[Illustration: Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7