2742 



Chapter 23 



WOOD 



WATER 



PULP 



BOARD 



WATER 



WET PROCESS 



WOOD 



I 



I 



PULP 



ADHESIVE 



BOARD 



DRY PROCESS 



Figure 23-2. — Schematic representation of wet and dry fiberboard processes. (Drawing 

 from Suchsland and Woodson 1985.) 



exterior, interior, and industrial; the exterior products account for about half tiie 

 tonnage manufactured (fig. 23-3). The market for sheathing, a major exterior 

 product, is expected to decline because of competition from gypsum board and 

 foil-backed structural-foam panels. Stricter flame-spread restrictions in building 

 codes, which favor mineral board and plastic substitutes, are also expected to 

 reduce use of interior building board and mobile-home board. 



Exterior. — Exterior-class boards are categorized as follows: sheathing, a 

 low-price board used in house construction for its moderate insulation value, 

 noise-control properties, and bracing strength; roof decking is laminated with 

 water-proof adhesive from sheets of insulation board to provide insulation and a 

 finished interior ceiling surface; roof insulation provides insulation but not a 



