Prefabricated forms are widely used for basement walls. They have several advantages: ready assembly into almost any size or shape from standard components; minimal amount of skilled labor required to erect them; versatility of combining into a large segment for one job using individually for another; and reduction of clutter from discarded formwork components of miscellaneous sizes, made possible by the large number of reuses. The preference of some contractors for job-built forms depends on the low initial cost of materials and their workmen's familiarity with it. Choice of formwork, however, should be matter of economics. Prefabricated systems offer unusual economy in labor for erection and most provide a great number of reuses. There is little defacing of the surface because ties are inserted through dadoes or slots provided in the side rails. There are several types of prefabricated forming systems: unframed 1 and one-eighth of an inch plywood panels for which the manufacturer supplies the necessary locking and ties and, for some designs, metal bracing attached on the back; steel channel frames 3 to 5 inches deep with any of several kinds of faces: aluminum frames with plywood facing; and cast or rolled aluminum facing, plain or textured, with integrally cast or bolted aluminum frame. The erection of formwork normally begins at a corner, starting with either the inside or outside form and setting it to a chalk line. Alternatively, a 2 by 4 kicker plate can be set to the chalk line of the footing using concrete nails and the formwork can then be attached to it. The first panel is set, plumbed and braced. Additional panels are set in sequence. These are ordinarily inserted as the first side is erected, starting at the first joint. Wales are attached to provide alignment and additional bracing is supplied as needed. Window and door bucks and boxouts should then be located and built. In setting the opposing forms care is needed to ensure alignment of joint lines so ties can be connected properly.