Molds for Reinforced Concrete.
Reinforced concrete, like every other new building material, has called forth ingenuity in many ways. When, for instance, a factory is to be reared much inventive carpentry is required to plan and construct the forms, or molds, into which the liquid concrete is to be poured around the steel skeletons. The footings, outside and inside columns, walls, girders, beams, floor-plates, roofs, and stairs all require separate forms, intelligently devised with a view to economy. For the Ingalls Building, Cincinnati, the forms cost $5.85 per cubic yard of concrete in place. White pine is the best wood for the purpose; it is readily worked and keeps its shape when exposed to wind and weather. For common buildings a cheaper wood, spruce or fir, may be chosen; even hemlock will serve if a rough finish suffices. In most cases green lumber is preferable to dry as less affected by water in the concrete. In fine work the boards of which the molds are made are oiled, and may be used over and over again. In all tasks a strict rule is that the reinforcing metal be properly placed and remain undisturbed as work proceeds.
Lock-woven wire-fabric.
W. N. Wight & Co.,
New York.