The commonest method of building monolithic walls of concrete is to use wooden forms. These are built in sets of panels, one for the exterior and the other for the interior face of each course. These are successively raised, one above the other, in pouring the walls. Mr. Ernest Flagg, architect, has developed a remarkably simple system of concrete-wall construction with the wooden form. Roughly broken stone are set against the inside of the forms, used for the exterior face of the wall, and the rest of the wall is filled up with concrete. By raising the boards which are used for the forms, as each layer hardens, the wall can be erected without skilled labor and yet have the appearance, on the exterior, of a stone wall. Of course it is necessary to point the joints of the stone work after the forms have been removed. Of the light steel forms, the most important on the market are the Metaforms and the Morrill forms. The Metaforms, originally the Reichert forms, are composed of individual form units. All units are standardized and interchangeable, and equipped with the necessary clamps and locking devices. These units are built of sheet steel, strongly reinforced, and measure 2 feet square. A single course of Metaforms is composed of an inner and outer shell of plates. As the work progresses the bottom course is taken off and placed above for the next, there being usually three courses of forms in operation. The Morrill form is also a sheet-steel form, only it uses a hinged "swing-up" construction, by which the lower courses of the form can be swung up into position for the new course as the work progresses. The Van Guilder double-wall machines have been gradually increasing in use throughout the country. They are not for. sale, but the company establishes a contracting organization in different centres. The machine is a steel mould which is moved along and upward as the concrete wall is tamped in it. It builds a double wall in tiers. Each tier is 9 inches high and 5 feet long. A complete circuit of one tier is made around the wall, and then the next tier is begun on top.
A double monolithic wall built by the Van Guilder machine.