Chapter 10 Floor Framing 243 Code Note Building codes specify that a sill must have a minimum level of protection against termite and decay damage. The IRC requires that all wood in contact with concrete or masonry be pressure-treated with a preserva- tive to prevent decay and insect damage. Location of the sill on the foundation depends on the type of exterior covering the building will have. The sill may be set flush with the outside edge of the foundation or it may be set back to allow for the thickness of the sheathing. In the case of brick veneer, sills may be set back even far- ther, Figure 10-18. To seal the crack between the bottom of the sill and the top of the foundation wall, a sill sealer is typically used. This seal stops passage of heated air through the space between the foundation and the sill. The sealer also keeps out dust and insects. Sills are usually 2 × 6 lumber. However, the width may vary depending on the type of con- struction. They are attached to the foundation wall with anchor bolts or straps. Code Note The IRC requires anchor bolts to be embedded at least 7″ into the concrete founda- tion, to have a minimum diameter of 1/2″, to be spaced no further than 6′ O.C. An anchor bolt is required within 12″ of the end of the sill, and each board in the sill must contain at least two anchor bolts. The size and spacing of anchors, however, is a matter of concern to each community. Always check the specifications in local building codes. 10.3.1 Termite Shields If termites are a problem in your locality, spe- cial shields must be installed. Some termites live underground and come to the surface to feed on wood. They may enter through cracks in masonry or build earthen tubes on the sides of masonry walls to reach the wood. The wood sill should be at least 8″ above the ground. Also, a protective metal shield should extend out over the foundation wall, as shown in Figure 10-19. The shield should be not less than 26 gage. 2" Material Toenail both sides A B Allow 3/8" space under ties Scab or cross tie Ledger Goodheart-Willcox Publisher Figure 10-17. Some carpenters like to butt joists over the girder. A—Joists are butted over a steel I-beam and wood 2 × 4 and secured with toenailing and a short scab of 2″ material. B—Joists are tied together with a scab or cross tie. Goodheart-Willcox Publisher Figure 10-18. This sill has been set back 4″ from the face of the foundation to allow for masonry to be applied later. Copyright Goodheart-Willcox Co., Inc.