Chapter 10 Floor Framing 247 Joists must also be doubled around openings in the floor frame for stairways, chimneys, and fireplaces, Figure 10-26. These joists are called trimmers. They support the headers that carry the tail joists. The tail joists are short joists that run from the band joist to the header of the open- ing. A carpenter must become thoroughly famil- iar with the plans at each floor level so adequate support can be provided. Select straight lumber for the band joist and lay out the standard spacing along its entire length, Figure 10-27. If an LVL rim board is used, it is manufactured straight. Add a line to mark the position for any doubled joists and trimmer joists that are required along openings. Where regular joists will become tail joists, change the X mark to a T, as shown in Figure 10-27. Dimension 1 1/2 smaller to allow for lap 14 1/2" 16" Sill Joists W-beam Header or band joist 16" 16" Rim joist A B C Goodheart-Willcox Publisher Figure 10-24. A—When joists lap over the center girder, spacing between the first joist and the rim joist is dif- ferent. B—Some carpenters set back the stringer and headers, leaving a ledge on the sill. The ledge is the same width as the thickness of the sheathing. C—The sheathing is flush with the foundation wall. Copyright Goodheart-Willcox Co., Inc.