Fiberboard and Hardboard

8 inches and also in sizes of 3/4 by 8 inches and 3/4 by 10 inches. “Anzac” siding is 3/4 by 12 inches in size. Usually, the finished width of bevel siding is about one-half inch less than the size listed. One side of beveled siding has a smooth planed surface, whereas the other has a rough resawn surface. For a stained finish, the rough or sawn side is exposed because wood stain works best and lasts longer on rough wood surfaces. DOLLY VARDEN.— Dolly Varden siding is similar to true bevel siding except that it has shiplap edges. The shiplap edges have a constant exposure distance (fig. 4-1). Because it lays flat against the studs, it is sometimes used for garages and similar buildings without sheathing. Diagonal bracing is therefore needed to stiffen the building and help the structure withstand strong winds and other twist and strain forces. DROP SIDING.— Regular drop siding can be obtained in several patterns, two of which are shown in figure 4-1. This siding, with matched or shiplap edges, is available in 1- by 6-inch and 1- by 8-inch sizes. It is commonly used for low-cost dwellings and for garages, usually without sheathing. Tests have shown that the tongue-and-grooved (matched) patterns have greater resistance to the penetration of wind-driven rain than the shiplap patterns, when both are treated with a water-repellent preservative. Fiberboard and Hardboard Fiberboard and hardboard sidings are also available in various forms. Some have a backing to provide rigidity and strength, whereas others are used directly over sheathing. Plywood horizontal lap siding, with a medium-density overlaid surface, is also available as an exterior covering material. It is usually 3/8 inch thick and 12 or 16 inches wide. It is applied in much the same manner as wood siding, except that a shingle wedge is used behind each vertical joint. A number of siding or paneling patterns can be used horizontally or vertically (fig. 4-1). These are manufactured in nominal 1-inch thicknesses and in widths from 4 to 12 inches. Both dressed and matched and shiplapped edges are available. The narrow and medium-width patterns are usually more satisfactory under moderate moisture content changes. Wide patterns are more successful if they are vertical-grained (to keep shrinkage to a minimum). The correct moisture content is necessary in tongue-and-groove material to prevent shrinkage and tongue exposure. Figure 4-2.-Vertica1 board siding. Treatment Treating the edges of drop, matched, and shiplapped sidings with water-repellent preservative helps prevent wind-driven rain from penetrating the joints exposed to the weather. In areas under wide overhangs or in porches or other protected sections, the treatment is not as important. Some manufacturers provide siding with this treatment already applied. Applications A method of siding application, popular for some architectural styles, uses rough-sawn boards and battens applied vertically. These can be arranged in three ways: board and batten, batten and board, and board and board (fig. 4-2). Sheet Materials A number of sheet materials are now available for use as siding. These include plywood in a variety of face treatments and species, and hardboard. Plywood or paper-overlaid plywood, also known as panel siding, is sometimes used without sheathing. Paper-overlaid plywood has many of the advantages of plywood besides providing a satisfactory base for paint. A medium-density overlaid plywood is not common. Stud spacing of 16 inches requires a minimum thickness of panel siding of three-eighths inch. However, 1/2- or 4-2