233 Floor Framing When the building foundation is completed and the concrete or mortar has properly set up, floor fram- ing may begin. Framing of the floor is often com- pleted before the foundation is backfilled. Installing the floor frame first helps the foundation withstand the pressure placed on it by the backfill material. On the other hand, backfilling may be done before the floor frame is installed. This offers two advantages: it makes delivery of lumber easier and allows convenient access for the start of framing. As described in Chapter 9, Footings and Foundations, a carpenter must make sure the foundation wall is adequately braced against damage or cave-in from the pressure of the back- filling. This is critical with concrete block walls. In any case, the site should be brought to rough- grade level after backfilling. The building’s basic design—such as one-story, two-story, or split level—often determines the type of framing used. Other factors may also influence the decision. In some parts of the country, for exam- ple, buildings must be constructed with special resis- tance to wind and rain. In other areas, earthquakes may be the greatest hazard. In cold climates, heavy loads of wet snow may require sturdier or special roof framing. All structures should be built to reduce the effects of lumber shrinkage and warping. They must also resist the hazard of fire. 10.1 Types of Framing There are three basic types of framing used in residential construction: Platform framing, also called western framing, is the most popular for residential construction. See Figure 10-1. Balloon framing is no longer used in new construction, but carpenters who remodel Learning Objectives After studying this chapter, you will be able to: Explain the difference between platform, balloon, and post-and-beam framing. Identify the main parts of a platform frame. Calculate the load on girders and beams used in residential construction. Lay out and install sills on a foundation wall. Describe how layouts are made on a header joist. Explain the correct procedure to follow when correcting problems with floor frames. Identify the parts of a floor truss. Describe materials used for subflooring. Estimate materials (sizes and amounts) required to construct a specific floor frame. Technical Terms balloon framing band joist blocking bridging cantilevered chord cross bridging crown deflection girder hanger header herringbone bridging I-joist joist ledger mudsill platform framing post anchor post-and-beam framing ribbon rough flooring sill sill plate sill sealer solid bridging span steel post stirrup subflooring tail joist trimmer underpinning web wide flange CHAPTER 10 Copyright Goodheart-Willcox Co., Inc.
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