Brick Sidewalks

BRICK SIDEWALKS. Brick sidewalks are very common, and when properly constructed are cheap, durable, and reasonably satisfactory. Commonly they consist of ordinary hard-burned building brick laid flatwise upon a porous bed of sand or cinders, although occasionally in heavily traveled business districts the bricks are set on edge and the joints are filled with cement mortar.

Foundation.

If the soil is a very retentive clay, or if the foundation is not well drained, the foundation should be excavated to a depth of 10 inches; but if the soil is an ordinary loam, c. depth of 8 inches is sufficient. All loose or spongy material should be removed; and the subgrade should be formed parallel to the surface of the finished walk.

Upon the subgrade should be spread a layer of clean coarse sand or fine gravel or cinders, to furnish a firm unyielding support for the bricks. If laid upon a foundation that became plastic when wet, the bricks would work down into the foundation and the mud would work up between the bricks, thus making the walk temporarily muddy and permanently rough. Whatever the material employed for the foundation, it should be thoroughly consolidated by tamping or rolling; and if cinders are used. par ticular care should be given to the tamping, so that the larger clinkers shall be broken up and the finer particles be worked in around the coarser pieces. A thorough flooding is beneficial in consolidating cinders, as the water aids in working the fine material into the interstices between the larger pieces. If flooded and well tamped, cinders will consolidate to about three fourths of their thickness when loose. Cinders containing fine ashes are undesir able for sidewalk foundations, since it is difficult to consolidate them, and since the ashes are likely to be washed to the bottom by rains and thereby to cause the surface of the sidewalk to settle. Cinders made by steam plants, sometimes called steam ashes, are better for this purpose than are household ashes, since the fires in the former are hotter and fuse most of the ashes into cinders, leaving little or no fine material. Steam cinders that have been drenched with water as soon as drawn from the furnace, usually called black cinders, are better than those that have been allowed to burn in the pile, since they contain fewer fine ashes.

Wood ashes are very objectionable, since they contain a great deal of fine material, and since a considerable part is soluble and will wash entirely away thus allowing the surface to settle.

Upon the foundation of gravel or cinders should be placed a layer of sand 11 or 2 inches deep to serve as a cushion upon which to lay the bricks (see § 761).

The Bricks.

The bricks should be hard-burned and have plane parallel surfaces and sharp right-angled edges. They should give a clear ringing sound when two are struck together, and when broken should show a compact uniform structure free from air bubbles and cracks. They need not be burned as hard as is re quired for carriage-way pavements (a 723); but they should be equally as carefully selected to secure a uniform quality and thereby insure uniform wear. Most sidewalks are made of hard burned ordinary building bricks; but sometimes they are con structed of re-pressed bricks, which give closer joints and more uniform surface. Thin joints are desirable, since they decrease the tendency for weeds and grass to grow in them. Sometimes sidewalk bricks are made with a corrugated top surface, of which Fig. 148, shows two forms; but the corrugations are of no advan tage, and it is hard to clean the snow out of them. Occasion ally salt-glazed brick (§ 734) are used in sidewalks; but this is undesirable, since the glazing makes the bricks slippery and also makes it more difficult to detect soft bricks.

Direction of Rows. There is considerable difference in practice as to the position of the bricks with reference to the side of the walk. The arrangement shown in Fig. 149, page 596, is apparently the most common, and may be called the longitudinal herring-bone. The arrangement in Fig. 150, page 596, is superior to that in Fig. 149, since there are usually no bricks in the lar corners near the edge of the walk, and weeds and grass grow in them, thus giving the walk an untidy appearance. Some manu facturers make triangular pieces with which to fill these corners, but such an arrangement will cost more than that shown in Fig.