Supplement - Structural Use Panels - American Wood Council

GUIDELINELRFD STRUCTURAL-USETO LRFD FOR STRUCTURALPANELS SUPPLEMENTCOMPOSITE LUMBER 5• Oriented Strand Board: Oriented strand board (OSB)is comprised of thin rectangular wood strands arrangedin a minimum of three cross-aligned layers and bondedunder heat and pressure with a waterproof and boilproofadhesive. OSB’s predecessor product waswaferboard, a wood panel product that was first commerciallyproduced in the mid-1960’s. Waferboardmanufacture involved a mat-formed panel product withrandom distribution of rectangular wafers. Orientedstrand board, a significantly improved structural panelcompared to waferboard, was first produced in the early1980’s.Oriented strand board is manufactured from hardwoodspecies, softwood species, and mixed species. The hardwoodspecies used are selectively harvested from foreststhat naturally regenerate. The softwood resource is derivedfrom fast-maturing species from managed forests.Much of the softwood resource represents selectiveharvesting from these managed forests.• COM-PLY ®: COM-PLY panels are composite panelsof wood veneer and other wood-based material. COM-PLYpanels are typically manufactured with five layers. Theouter layers and the center layer are wood veneer, andthe two remaining core layers are comprised of woodfiber sandwiched between the veneer layers. COM-PLYpanels are manufactured with waterproof adhesives.COM-PLY was developed as a cooperative effort ofthe U.S. Forest Service and APA to more efficientlyutilize the wood resource.Exposure DurabilityThe following exposure durability classifications arebased on product composition and adhesive bond durability.• Exterior: Exterior panels may be used in applicationsthat are permanently exposed to the weather or to moisture.• Exposure 1: Exposure 1 panels may be used in applicationsthat are not permanently exposed to weather ormoisture, but where resistance to moisture effects dueto high humidity, water leakage, exposure during constructiondelays, or similar exposure conditions, isrequired.• Exposure 2: Exposure 2 panels may be used for interiorapplications requiring resistance to effects of highhumidity and water leakage.2INTRODUCTION2.2 Typical ApplicationsPanel ApplicationsIn addition to roof, subfloor, wall, and single-layerfloor applications, structural-use panels are used in otherapplications. Such applications include structural-insulatedpanels, I-joist webs, materials handling systems (pallets,bins, crating), transportation equipment, and concreteforming.Shear Walls and DiaphragmsStructural-use panels are used as components of wall,floor, and roof systems to resist and transfer in-plane forcesas may be imposed by wind or seismic loading. Shear wallsand diaphragms represent an important application forstructural-use panels.2.3 AvailabilityAlthough other panel constructions may be available,Table 2.1 shows constructions most typically manufactured.Check with suppliers concerning availability.APA/EWS