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APA - The Engineered Wood Association, The Leading Resource for Information About Engineered Wood Products™

Lesson 4: Oriented Strand Board (OSB)

Oriented strand board (OSB) is sometimes mistaken for "particleboard," "flakeboard," or "chipboard." OSB is none of these; it is a high quality, structural panel product. Unlike particleboard and flakeboard, OSB is manufactured in a cross-oriented pattern similar to plywood to create a panel with enhanced structural performance.


OSB is composed of rectangularly shaped wood strands arranged in layers at right angles to one another, which are laid-up into mats that form a panel. Cross-orientation makes the panels strong and stiff in both directions. This manufacturing process also ensures panel consistency; OSB contains no laps, gaps, or voids.

OSB is bonded with fully waterproof adhesives. Most panels are also treated with a sealant on the panel edges to retard moisture penetration. As an added feature, panels may be textured on at least one side to provide a slip-resistant surface for roof sheathing installation.


OSB is popular for residential, nonresidential, and industrial applications. APA-trademarked OSB is suitable for a variety of end uses including subflooring, single-layer flooring, wall and roof sheathing, sheathing ceiling/deck, structural insulated panels, webs for wood I-joists, industrial containers, mezzanine decks, and furniture.

How is OSB Manufactured?

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Recommended PDF Resources
Performance Rated Panels ( K)

Background, benefits, performance testing criteria, and code recognitions for APA Performance-Rated Panels. Covers plywood, oriented strand board, and composite panels. Typical trademarks illustrated and explained. (Form F405 - 12 pages)

Oriented Strand Board ( K)

Describes OSB composition, properties, code acceptances, and applications. (Form W410 - 12 pages)