The ornamental effects to be obtained by the varied use of bricks are exceedingly numerous. First, there are the constructive features, such as arches, impost courses, pilasters, belt and string courses, cornices and panels; then there is a large field for design in surface ornament, by means of brick of different shades or color, laid so as to form a pattern.
For the constructive features both plain and moulded bricks may be used, although only very plain effects can be produced by plain brick alone.
In nearly all of our large cities, and especially those near which pressed brick are manufactured, a great variety of moulded bricks can be obtained, by means of which it is possible to construct almost any moulding, belt course, etc., that may be desired.
Belt courses and cornices, and in fact any moulded work built of brick, is much cheaper than the same mouldings cut in stone.
In designing brick details a point to be observed is that the projection should be kept small.
The top of all belt courses should have a wash on top, as shown in Fig. 124.
The top course, W, should be laid as stretchers when the projection is not over 3 inches to reduce the number of end joints, and the bricks should also be laid in cement mortar, so that the mortar in the end joints will not be washed out.
If W is a stretcher course, at least every other brick in the course below should be a header. If a beveled brick cannot be obtained for the top course, and a plain brick must be used, its upper surface should be protected by sheet lead built into the second joint above it, as shown at A, Fig. 125, or the top of the bricks may be plastered with Portland cement, as shown at B. Unless some such precaution is taken to protect the top of the projecting brick from the wet, the rain water will after a while soften the mortar in the joint, P, and penetrate into the wall. The end joints in the belt course are always liable to be washed out.
Belt courses and cornices should always be well tied to the wall by using plenty of headers or iron ties. The top of the wall should also be well anchored to the rafters or ceiling joist by iron anchors, as the projection of the cornice tends to throw the wall outward.
In using moulded brick in string courses and cornices it is more -economical to use bricks that can be laid as stretchers, as it, of course, takes a less number of stretchers than of headers to fill a given length, and the bricks cost the same.
One of the greatest objections to brick mouldings is the difficulty of getting them perfectly straight and true. Nearly all moulded brick become more or less distorted in moulding and burning, so that when laid the abutting ends do not match evenly, and the moulding presents the appearance shown in Fig. 126.
Some makes of brick, however, are quite free from these defects, and before selecting moulded bricks to be used in this way the architect should endeavor to ascertain which makes are the truest and give the most perfect work.
By being very careful in laying the bricks to average the defects, and by ruling the joints, the effect of the distortion may be largely overcome. Headers do not show the distortion as much as stretchers.