Chapter 5 Interior Finish of Walls and Ceilings

CHAPTER 5 INTERIOR FINISH OF WALLS AND CEILINGS Builders are responsible for finishing the interior of the buildings of a construction project. Interior finish consists mainly of the coverings of the rough walls, ceilings, and floors, and installing doors and windows with trim and hardware. In this chapter, we’ll discuss wall and ceiling coverings, including the closely related topics of insulation and ventilation. In the next chapter, we’ll look at floor coverings, stairway construction, and interior door and wood trim installation. DRYWALL AND OTHER COVERINGS LEARNING OBJECTIVE: Upon completing this section, you should be able to describe drywall installation and finishing procedures, and identify various types of wall and ceiling coverings and the tools, fasteners, and accessories used in installation. Though lath-and-plaster finish is still used in building construction today, drywall finish has become the most popular. Drywall finish saves time in construction, whereas plaster finish requires drying time before other interior work can be started. Drywall finish requires only short drying time since little, if any, water is required for application. However, a gypsum drywall demands a moderately low moisture content of the framing members to prevent “nail-pops.” Nail-pops result when frame members dry out to moisture equilibrium, causing the nailhead to form small “humps” on the surface of the board. Stud alignment is also important for single-layer gypsum finish to prevent a wavy, uneven appearance. Thus, there are advantages to both plaster and gypsum drywall finishes and each should be considered along with the initial cost and maintenance. DRYWALL There are many types of drywall. One of the most widely used is gypsum board in 4- by 8-foot sheets. Gypsum board is also available in lengths up to 16 feet. These lengths are used in horizontal application. Plywood, hardboard, fiberboard, particleboard, wood paneling, and similar types are also used. Many of these drywall finishes come prefinished. The use of thin sheet materials, such as gypsum board or plywood, requires that studs and ceiling joists have good alignment to provide a smooth, even surface. Wood sheathing often corrects misaligned studs on exterior walls. A strongback (fig. 5-1) provides for alignment of ceiling joists of unfinished attics. It can also be used at the center of a span when ceiling joists are uneven. Gypsum wallboard is the most commonly used wall and ceiling covering in construction today. Because gypsum is nonflammable and durable, it is appropriate for application inmost building types. Sheets of drywall are nailed or screwed into place, and nail indentions or “dimples” are filled with joint compound. Joints between adjoining sheets are built up with special tape and several layers (usually three) of joint compound. Drywall is easily installed, though joint work can be tedious. Drywall varies in composition, thickness, and edge shape. The most common sizes with tapered edges are 1/2 inch by 4 feet by 8 feet and 1/2 inch by 4 feet by 12 feet. Regular gypsum board is commonly used on walls and ceilings and is available in various thicknesses. The most common thicknesses are 1/2 inch and 5/8 inch. Type X gypsum board has special additives that make it fire resistant. Figure 5-1.—Strongback for alignment of ceiling joists. 5-1