Bridging. To add to the carrying power of floor joists, bridging is cut in between them as shown in Fig. 23. For ordinary dwellings l"x 3" stock will serve. On large work, stock two inches thick should be made use of. Bridging should be spaced not more than 8 feet apart. A miter-box, set at the appropriate angle, may be used in cutting bridging, all the pieces being cut at one time with the exception of those for the odd spacings at the side or end of a room. A more common practice is to take a piece of stock, and, after cutting a bevel on one end, place it as in F'ig. 23 with the beveled end above the lower edge of the joist against which it rests, a distance slightly in excess of the thickness of the stock; then saw as indicated, sawing vertically and along the joist.
Fig. 23. Cutting Bridging.
Fig. 24. Laying off a Stay.
Before placing bridging, the joist must be spaced and properly fastened in place. This is done by placing a piece of stock, 1" x 6 " or 2"x4", as in Fig. 24. With a try square, mark the locations of the joists. This board may then be transferred to the center of the room and the joists there spaced according to the marks, and held in place by being "tacked." A second method consists in placing the spacing board in the center of the room and having a second person sight the joists for straightness while the first party places them as directed and tacks them. This tacking consists in driving the nails only partially in, leaving the heads project enough that they may later be withdrawn with a claw hammer. Still another method is to lay off the "stay" by measurement with the framing square so that it corresponds with the spacings of the joists at the side walls.
Fig. 25-a-b. Headers and Trimmers in Floor Frame.
Bridging should be nailed with two nails at each end of the piece.