Terminology

• Strands: rectangular wood pieces about 2.5 × 15 cm
• Waferboard: panel of non-oriented flakes with phenolic resin
• PMDI: isocyanate adhesive used in some OSB cores
• EN 300 grades OSB/0 to OSB/4: European grades by mechanical performance and moisture resistance
• Type 1 to Type 4: resin classes, from nonstructural to damp or outdoor use

History and demand

Invention

• 1963: invented by Armin Elmendorf in California

Sourcing

• 2023: China produced about 11 million m3, falling to 9.1 million m3 in 2024; Canada about 7.42 million m3; EU27, UK, and EFTA 6.6 million m3; Germany 1.213 million m3 in 2024
• Romania became Europe's largest OSB exporter in 2014

Demand trend

• 66 percent of the North American structural panel market in 2016; Canada produced 10.5 million m² in 2005, mostly exported to the United States

Composition and production

Raw materials

• Strands bonded with wax and synthetic resin; urea-formaldehyde (Type 1, nonstructural, not waterproof); isocyanate (PMDI) in the core with melamine-urea-formaldehyde or phenol-formaldehyde on the surface (Type 2); phenol-formaldehyde throughout (Types 3 and 4, damp or outdoor)

Manufacturing process

• External layers align with the panel's strength axis and internal layers run perpendicular; pressed in a heated press

Properties

Mechanical

• Greater load-bearing capacity than milled wood panels when tested to failure

Thermal and moisture

• No internal voids; can be water-resistant but needs membranes for full water protection and is not recommended for exterior use

Standards

Material specifications

• DOC PS 2: wood structural panels (named in the building code)
• EN 300: European OSB grades

Uses in buildings

Building elements

• Wood-Framed Walls, Wood-Framed Floors, Shear Walls: wall, roof, and floor sheathing and structural panel diaphragms
• Wood I-Joists: web material

Pros and cons

Pros

• No internal voids
• Cheaper and more uniform than plywood
• Holds 66 percent of the North American structural panel market

Cons

• Not recommended for exterior use without protection
• Formaldehyde emissions are a concern with urea-formaldehyde types (industry calls North American emissions negligible)

Sustainability

Health

• Isocyanate-based panels contain no formaldehyde; urea-formaldehyde is the most toxic option

Manufacturing and cost

Main manufacturers and suppliers

• LP Building Solutions
• Weyerhaeuser
• Huber Engineered Woods
• Georgia-Pacific

Trade association: APA – The Engineered Wood Association.

Sources

• Wikipedia: Oriented strand board, https://en.wikipedia.org/wiki/Oriented_strand_board
• UpCodes: 2024 IBC Chapter 23 wood, https://up.codes/viewer/department-of-defense/ibc-2024/chapter/23/wood
• Wikimedia Commons: Oriented strand board at Courtabœuf 2011.jpg, photo by Lionel Allorge (CC BY-SA 3.0), https://commons.wikimedia.org/wiki/File:Oriented_strand_board_at_Courtabœuf_2011.jpg
• IndexBox: China oriented strandboard market overview 2024, https://www.indexbox.io/blog/oriented-strandboard-osb-china-market-overview-2024-4/
• Reportlinker: oriented strand board production in Canada, https://www.reportlinker.com/dataset/896d7b6c90bb1e79b120d9ff564426d8d0039564
• EUWID: German OSB production on par with prior year level in 2023, https://www.euwid-wood-products.com/news/wood-based-panels/german-osb-production-on-par-with-prior-year-level-in-2023-100424/