Placing Posts and Girders

Figure 1-14.—Spaced wood girders. joints between the planks are staggered. In framing, a built-up girder is placed so that the joints on the outside of the girder fall directly over a post. Three 16-penny (16d) nails are driven at the ends of the planks, and other nails are staggered 32 inches OC. As shown in figure 1-13, the top of the girder is flush with the top sill plate. When space is required for heat ducts in a partition supported on a girder, a spaced wood girder, such as that shown in figure 1-14, is sometimes necessary. Solid blocking is used at intervals between the two members. A single-post support for a spaced girder usually requires a bolster, preferably metal, with a sufficient span to support the two members. The ends of a girder often rest in pockets prepared in a concrete wall (fig. 1-13). Here, the girder ends must bear at least 4 inches on the wall, and the pocket should be large enough to provide a 1/2-inch air space around the sides and end of the girder. To protect against termites, treat the ends of the girder with a preservative. As a further precaution, line the pockets with metal. Steel S-beams (standard) or W-beams (wide flange), both shown in figure 1-15, are most often used as girders in wood-framed construction. Whether the beam is wood or steel, make sure it aligns from end to end and side to side. Also make sure the length of the bearing post under the girder is correct to ensure the girder is properly supported. PLACING POSTS AND GIRDERS Posts must be cut to length and set up before the girders can be installed. The upper surface of the girder may be in line with the foundation plate sill, or the girder ends may rest on top of the walls. Long girders must be Figure 1-15—Types of steel beams. 1-7