Turning Pieces and Centers for Arches

Abstract

To enable a bricklayer to construct an arch over an opening in the wall of a building, the carpenter must provide him with a support on which he can lay his bricks to shape the arch. This support can be either a solid piece of timber cut to the shape of the bottom edge of the arch (figure 7.1) — which is called a turning piece — or a timber frame as shown in figure 7.2, which is called a center. The height of an arch and the thickness of the wall will dictate whether a turning piece or a center is to be provided. Usually, turning pieces are used only for fairly low segmental arches and for flat arches.