14. Walls of bricks

In many cases, bricks — and concrete blocks, too — are very satisfactory for use in the construction of walls. 'They are strong, durable, prefabricated units that can be erected easily. Bricks generally present a pleasing appear­ance and can be obtained with various qualities, colors, and textures. On the other hand, they are heavy.

The quality of the mortar and the excellence of the workmanship used in its construction are likely to control the strength, waterproof-ness, and durability of a brick wall. The bricks themselves are gener­ally manufactured under well supervised and controlled conditions.

Brickwork should be constructed with completely filled joints, and the bricks themselves should be placed in accordance with some pre­determined pattern that gives adequate bond.

Curtain-wall construction is often used for brick walls of impor­tant industrial plants. Here the brick work is a filler and is support­ed both vertically and laterally by the framework of the structure.

Brickwork may be reinforced with steel so as to act somewhat like reinforced concrete although, of course, it is limited in strength and usefulness. High parapet walls, and others that are not braced at their tops, may have pilasters or buttresses reinforced as vertical cantilevers, and the walls between them may be reinforced as hori­zontal beams.

Another use of reinforcement in brick construction is for the pur­pose of knitting the brickwork together to resist earthquake tremors. It is obvious that the walls should also be mechanically attached to the skeleton framework of the structure.

When planning reinforced brickwork, one should consider the joints and the way the bricks will be laid up. In horizontal joints, the sizes of rods should not exceed 1/4 in., as otherwise the joints will become too thick.

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15. Disadvantages of the brick walls

Solid brick walls alone are not good insulators. Sweating at the inside surface during cold weather is also to be avoided. Furthermore, the heat capacity of heavy walls may retard the rate of warming up a room on a winter morning, and it may similarly cause a room to remain hot for some time after the walls have once become heated by the summer sun.

One way to remedy these disadvantages is to build the walls so that they are of the hollow-cavity type. The brickwork should be carefully bonded together; corrodible metal ties should not be trusted for this. The air spaces should also have drains at their bottoms in order to remove any leakage and condensation. Special bricks with holes through them may, if laid properly, serve partly in remedying insulation and condensation troubles.

The prevention of leakage of moisture through brickwork is a matter deserving thoughtful study. The proper mortaring, of all joints is one helpful feature; flashing is another.

There are many conflicting ideas about how to install flashing and even about the best materials to use. Flashing may be especially de­sirable under copings, at window heads, at floor lines and above steel beams — even above concrete ones. Whether the flashing is copper, felt and asphalt, or some other material, care should be used to avoid planes of weakness in the walls, and to see that the walls are supported properly.

Incidentally, horizontal surfaces of brickwork left exposed to the elements are likely to disintegrate at the joints. This should be re­membered when chimneys, parapets, platforms, areaways, and perhaps even window sills are planned.

Many of the features that have been mentioned concerning brick walls are applicable to walls composed of concrete blocks, stone ma­sonry, precast concrete, cement blocks, and other prefabri­cated masonry materials.

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