This section is from the book "A Treatise On Architecture And Building Construction Vol2: Masonry. Carpentry. Joinery", by The Colliery Engineer Co. Also available from Amazon: A Treatise On Architecture And Building Construction.
252. There are numerous ornamental effects produced by the varied use of bricks. First, there are the constructive features, such as arches, imposts, pilasters, belt and string courses, cornices, and panels. There is also a large field for design in surface ornament by means of brick of different shades or color laid to form a pattern. Both plain and molded brick may be used, although no very striking effects can be produced by the use of plain brick alone.
In most of the large cities there are manufactories of pressed brick, making a great variety of molded brick, by means of which almost any design in moldings, belt courses, etc. may be carried out. Molded-brick cornices, belt courses, and indeed any molded work built of brick are much cheaper than stone.
253. It is difficult in laying brick moldings to get them to run true and straight. Nearly all molded brick become somewhat uneven and distorted in contour from molding and burning, so that when they are laid in the wall, the ends that come against each other do not match evenly. Some manufacturers make molded brick that are almost, if not entirely, free from this defect; and if molded brick are to be used, the architect should endeavor to learn which kinds run the truest and make the most satisfactory work.
If the bricks are carefully averaged when laid, so that the ends will match as nearly as possible, and the joints are neatly ruled, the uneven effect may be largely overcome. The distortion shows less in header brick than in stretcher, because they have less surface to distort.
254. The projection of the brick in moldings, belt courses, etc. should be as small as possible to carry out the design, in order that the brick may bond back into the wall. If the projection is too great, there is danger of the brick falling out.
When practicable, and the projection is not too great, it is better to use more stretchers than headers in a belt course, because it takes a less number of stretchers than headers to run a given number of feet, and the cost of the bricks is the same.
255. If possible, the top of all brick belt cornices should be laid in beveled brick, so as to give a wash to the top of the course. This is shown in Fig. 106, where a shows the beveled brick on top of the belt course, and b the coved brick under the top course. The top course a should be laid as a stretcher course, provided it does not project more than 3 inches from the face of the wall; this reduces the number of end joints in the brickwork. The brick should be laid in cement, so that the mortar in the joints will not be washed out. If the top course a is built as a stretcher course, the course b should have at least every other brick a header.
256. When it is not possible to use beveled brick for the top course, some other means of protecting the upper surface should be used, as unless some precaution is taken to protect the top of the projecting brick from the wet, the rain water will eventually soften the joint and penetrate into the wall. The end joints of the top courses are especially likely to be washed out. Fig. 107 shows the best method of protecting the top courses, when beveled brick are not used; this is by means of lead sheets built into the second joint above the belt course, and turned down slightly over the face.
Another method consists of a beveled course of Portland cement, as shown at a, Fig. 108. This is not considered as good as the lead, since the cement may become cracked and fall off.