Copyright Goodheart-Willcox Co., Inc. Unit 12 Residential Framing Prints 207 Figure 12-4, are engineered wood members commonly used in floor construction. Wood I-joists have flanges made from solid sawn lumber or laminated veneer lumber (LVL) and a web made from oriented strand board (OSB) or plywood. • Subfloor. The joists and header are covered with subflooring. A sheet material, such as plywood or chip board, is normally used. The subfloor is fastened to the joists using nails or screws. Often, construction adhesive is used to attach the subfloor to the joists before installing fasteners to strengthen the assembly. The finished floor, such as carpet, wood, or ceramic tile, will cover the subfloor. Additional floor framing members are shown in Figure 12-5: • Double header. When an opening that disrupts the framing pattern is needed, a double header is installed perpendicular to the joists. The same size member that is used for the joists is used. • Double trimmer. A double trimmer consists of two joists nailed together next to an opening. • Tail joist. This is a joist interrupted by an opening. Tail joists normally run between the double header and the sill plate. • Ledger. A ledger is a small piece of lumber, such r as a 2×2, nailed to the side of the double header, at its bottom edge. This piece serves as a ledge on which each tail joist rests. A notch must be cut into the joist to keep the top of the joist even. • Bridging. Bridging consists of small members g connected between the sides of adjacent joists to provide bracing. Bridging provides lateral stability for the joists and helps to transmit the load between the joists. Many types of bridging are used, including joist-sized members, crossed 2×4s, and crossed sheet metal bars. × × The floor framing system is often shown on the floor framing plan. The sizes of the members are given and marks or arrowheads are used to indicate the direction of the span. A note is typically used to specify dimensions for joists: 2×12 JOISTS 16″ O.C. ″ This designation means that a 2×12 member is used for each joist and the joists are spaced 16″ from one another ″ on center (O.C.). A measurement specified with the abbreviation O.C. or o/c refers to the distance between the centers of the adjoining building components. Joists on a plan represent the joists above the level shown. For example, joists shown on a foundation plan would be located above the basement and below the first e floor. See Figure 12-6. Dan Dorfmueller Figure 12-3. Wood floor joists framed over an interior loadbearing partition and foundation walls. APA-The Engineered Wood Association Figure 12-4. Wood I-joists are lightweight, high-strength framing members used for long spans. Common depths range from 9 1/2″ to 16″ ″ and flange widths vary from 1 1/2″ ″ to 3 1/2″. Member lengths up to 66′ are available. Engineered Wood Products The e development pm of modern enginee er e ed wood o produc u ct s has done much to supp p po rt th he movem o me nt to t ow ard green construction. n Accor rd ing n to the t Engine n ee red Wood Association, , I I- joists s use e 50% 0 less ss wood than solid sawn 2× 2 × joists s. LVL L, freque en tly used for girders and rim r m boardsa s, als so conserves rv wood by providing the e requir re d strength e g char a ra cteristics while using less es woo od . Lam mi n na ted strand st lumber (LSL) further e r conserv ve s res so urces r because be it can be manufactured ct from f m small-diameter, m - et misshapen trees that t would w oth he rwise w be e unusable. Because engine n ee red wood pro od ucts can an be purchased in any leng n gt h, th he waste a at the e construction site is great tl y y reducedu d. GREEN BUILDING