This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol1", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
Fig. 114 shows the diagonal work sloping in the opposite direction. A course of diagonal work is built into the wall at intervals of from three to eight courses. Suppose it is decided to build a 3 1/2-brick wall with diagonal courses at intervals of five courses. Then four courses of ordinary brickwork will be built; then one course as in Fig. 114; then four more courses of ordinary brickwork, and then one course as in Fig.
115; and so on.
It is better to have an even number of courses between the diagonal courses in walls of an odd number of half-bricks in thickness, as this arrangement increases the bonding effect of the diagonally laid bricks, as will be seen by superimposing a tracing of Fig. 114 over Fig. 115.
When a wall is of an even number of half-bricks in thickness the arrangement is somewhat different. The facings are laid as before, and the angle and the whole of the heading course is filled up with headers as in ordinary brickwork. The stretching course is filled up with bricks laid diagonally and in the manner already explained, the shaded portions in Figs. 118 and 119 corresponding with the shaded portions in Figs. 114 and 115. An even number of courses of ordinary brickwork should come between the courses of diagonal work, so that a wall will be built up as follows: One course as in Fig. 118; one course as in Fig. 119; an even number of courses of ordinary brickwork; one course similar to Fig. 118, but with the diagonal bricks sloping in the opposite direction; one course similar to Fig. 119, with the diagonal bricks sloping in the opposite direction; and so on.
The diagonal work is used in one wing only of any course, as it is undesirable that it should occur in the heading course. Such an arrangement would decrease the area of the diagonal work, and consequently decrease the longitudinal strength of the wall.
This form of bond is used for the same purpose as diagonal bond in walls three bricks thick and upwards, but is most commonly used for walls over four bricks thick. The facings are laid in the usual manner, and the interior of the herring-boned course is filled up with bricks laid as shown in Figs. 116 and 117, the method of procedure being as follows: Lay the brick A (Figs.
116 and 117) with the corners a and b on the facings, and with its sides at 45 degrees to the faces of the wall. Lay bricks end to end with A until the last brick B reaches the centre of the wall as nearly as possible. Next lay the brick C at right angles to B, and lay other bricks end to end with C until the facing bricks are reached, the last brick laid being cut to fit if necessary. The rest of the work is then filled up, as shown in Figs. 116 and 117, whole bricks being used against the facing bricks to correspond with A.
In walls of an odd number of half-bricks the herringbone work may be carried round the angle as shown in Fig. 116, but in walls of an even number of half-bricks the angle and the heading course should be filled in with headers in the usual manner, and the stretching course filled with herring-bone work, as in Fig. 117.
The remarks made above with regard to the vertical spacing of the diagonal courses applies equally well to the spacing of herring-bone courses; and in alternate courses of herring-bone work the direction of the bricks is reversed.
A good method - increasing the longitudinal strength of brick walls built in any kind of bond - is by building in rows of hoop iron, 1 by 1/16 inch, at intervals between the courses, as shown in Fig. 120, in the direction of its length, one row being used for each half-brick in the thickness of the wall. The iron should be thoroughly tarred and sanded before use in order to prevent oxidation. The methods of joining lengths of hoop and of forming angles therein are shown at A and B, Fig. 120, respectively.
Hoop iron may be used with advantage when great strength is required, or when it is impossible to obtain a satisfactory bond by the overlapping of the bricks; but as iron expands when exposed to heat, this construction is not to be recommended in a building which is intended to be fire resisting.