Forms For Concrete Walls. The economical building of forms for concrete walls is a matter of importance in building construction. Fig. 12 shows a type of form suitable for foundation work. Such forms should be made of semi-seasoned stock. Thoroly seasoned stock will warp badly when the wet concrete is placed. Spruce, Norway pine, etc., are better woods to use than hard or Georgia pine.

For ordinary foundation work 1-inch boards may be used, the studs being placed not over 2 feet apart. These studs may be assisted materially in holding the forms in position, by wires placed as in Fig. 12, and by props placed against the dirt wall of the excavation.

In placing the concrete a 4-inch layer is laid and then " spaded " or "worked" well into place, a "wet mix" being used. The smoothness of the resulting faces is increased by an additional spading of the mixture away from the form. A good spading tool is made by straightening out an ordinary garden hoe. This allows the cement and mortar to flow next to the form and hold this place while the filling proceeds.

Where forms are placed to give finished walls, that is, walls to which no plaster is to be applied, they should be aligned with no greater variation than 3/8" from the lines specified.

Forms should be allowed to remain until the concrete will resist indentation with the thumb, upon ordinary walls.

There is no limit to the ingenuity one may make use of in form building. The illustration given is merely suggestive.