Copyright Goodheart-Willcox Co., Inc. 302 Section 4 Construction Details The head is the top of a window or door. The jambs are the vertical sides of a door or window. The sill is the bottom piece connecting the jambs. Sills A sill channels water away from a building. A sill either consists of a single unit or multiple units. It can be built in place or prefabricated. Single unit sills are either slip sills or lug sills. See Figure 14-55 and Figure 14-56. Slip sills are the same length as the window opening lug sills extend into the masonry on either side of the opening. A slip sill can be left out when the opening is being laid and set at a later time. A lug sill, however, must be set when the masonry is up to the bottom of the window or door opening. Sills are usually made of cut stone, brick, concrete, or metal. See Figure 14-57 and Figure 14-58. Joints for Movement in Masonry Changes in volume of masonry materials result in movement. Joints are needed to allow these movements to occur and to prevent cracks in the construction. Goodheart-Willcox Publisher Figure 14-54. Typical door sill construction in masonry walls. Jamb block Trim Flush door Flush door Precast concrete sill Caulking Solid concrete block Masonry bridging 8" Precast concrete joist Joist section Brick molding Jamb block Metal threshold Concrete floor Precast Sill for Wood Door Sill as Part of Basement Floor Goodheart-Willcox Publisher Figure 14-55. Stone slip sill. Goodheart-Willcox Publisher Figure 14-56. How lug and slip sills of stone or cast con- crete fit into a brick wall. Lug Sill Slip Sill