Chapter 10 Floor Framing 251 Safety Note Use great care in working with I-joists. They are unstable until properly braced. Failing to observe the following precautions and prac- tices could cause accidents and damage: • Never allow workers to walk on joists until the joists are braced. • Do not stack building materials on unsheathed joists. Rather, place them only over beams or walls. • Subflooring must be completely attached to each joist before additional loading of the floor. • Install and nail all blocking, hangers, and rim boards at the ends of the joists. • To temporarily brace joists, provide a rigid structure such as a braced wall or permanent deck (sheathing) nailed to the first 4′ of the joists. • Attach 1 × 4 struts from the braced area across the tops of the rest of the joists. Unless this is done, sideways buckling or a rollover is likely. • When joists are cantilevered, struts must be attached to both the top and bottom flanges. • Keep flanges straight with a tolerance of no more than 1/2″ of true alignment. 10.4.5 Installing Solid Wood Joists After the band joists are laid out, toenail them to the sill. Position all full-length joists with the crown turned up. Tightly hold the end against the band joist and along the layout line so the sides of the joist are plumb. Butt the joists against the band joist and fasten them with 16d nails. Next, fasten the joists along the opposite wall. If the joists butt at the girder, they should be con- nected with a scarf or metal fastener. If they lap, they can be nailed together using 10d nails. Use 8d nails to toenail the joists to the girder. Nail doubled joists together using 10d nails spaced about 1′ along the top and bottom edges. First, check that the crowns of the joists are at the same height. If not, toenail through the higher one to bring them to the same level. Next, drive sev- eral nails straight through to tightly pull the two surfaces together. Clinch the protruding ends. Finish the nailing pattern, driving the nails at a slight angle. Some carpenters lay a bead of caulk along the joint formed by the band joist and the sill to keep out air and dust. A sill sealer serves the same purpose. Thinking Green The development of modern engineered wood products has done much to support the movement toward green construction. According to the APA—The Engineered Wood Association, I-joists use 50% less wood than old-style sawn 2 × joists. LVL, frequently used for girders and rim boards, also conserves wood by providing the required strength char- acteristics while using less wood. LSL further conserves resources because it can be manu- factured from small-diameter, misshapen trees that would otherwise be unusable. Because engineered wood products can be purchased in any length, the waste at the construction site is greatly reduced. 10.4.6 Framing Openings Place 1″ boards or sheets of plywood across the joists to provide a temporary working deck for installing header and tail joists for the opening. First, nail in the trimmer joists. As described earlier, a trim- mer is a full-length joist or a stud that reinforces a rough opening. Sometimes, a regular joist is located where it can serve as the first trimmer. Figure 10-31 is a plan view of a finished assembly. The length of the headers can be determined from the layout on the band joist. Cut headers and tail joists to length. Make the cuts square and true. Considerable strength will be lost in the fin- ished assembly if the members do not tightly fit together. Lay out the position of the tail joists on the headers by transferring the marks from the band joist. Pro Tip Be accurate in laying out and cutting floor framing members. The strength of the assembly depends on all of the parts tightly fitting together. Copyright Goodheart-Willcox Co., Inc.