World Library  
Flag as Inappropriate
Email this Article

Oriented strand board

Article Id: WHEBN0000276546
Reproduction Date:

Title: Oriented strand board  
Author: World Heritage Encyclopedia
Language: English
Subject: Particle board, Engineered wood, Pulpwood, Framing (construction), Wood processing
Collection: Composite Materials, Engineered Wood
Publisher: World Heritage Encyclopedia

Oriented strand board

OSB is easily identifiable by its characteristic wood strands.

Oriented strand board (OSB), also known as sterling board, sterling OSB, aspenite, and smartply in British English, is an engineered wood particle board formed by adding adhesives and then compressing layers of wood strands (flakes) in specific orientations. It was invented by Armin Elmendorf, California US in 1963 OSB Patent. OSB may have a rough and variegated surface with the individual strips of around 2.5 × 15 cm (1" × 6"), lying unevenly across each other and comes in a variety of types and thicknesses.


  • Uses 1
  • Manufacturing 2
  • Related products 3
  • Production 4
  • Properties 5
    • Types 5.1
  • References 6
  • External links 7


OSB is used in housing construction.

OSB is a material with high mechanical properties that make it particularly suitable for load-bearing applications in construction.[1] The most common uses are as sheathing in walls, flooring, and roof decking. For exterior wall applications, panels are available with a radiant-barrier layer pre-laminated to one side; this eases installation and increases energy performance of the building envelope. OSB also sees some use in furniture production.


OSB in production before gluing in a thermal press

Oriented strand board is manufactured in wide mats from cross-oriented layers of thin, rectangular wooden strips compressed and bonded together with wax and synthetic resin adhesives (95% wood, 5% wax and resin). The layers are created by shredding the wood into strips, which are sifted and then oriented on a belt or wire cauls. The mat is made in a forming line. Wood strips on the external layers are aligned to the panel's strength axis, while internal layers are perpendicular. The number of layers placed is determined partly by the thickness of the panel but is limited by the equipment installed at the manufacturing site. Individual layers can also vary in thickness to give different finished panel thicknesses (typically, a 15 cm layer will produce a 15 mm panel thickness). The mat is placed in a thermal press to compress the flakes and bond them by heat activation and curing of the resin that has been coated on the flakes. Individual panels are then cut from the mats into finished sizes. Most of the world's OSB is made in the United States and Canada in large production facilities. The largest production facilities can make over 1,000,000 square feet (93,000 square metres) of OSB per day.

Related products

Materials other than wood have been used to produce products similar to oriented strand board. Oriented structural straw board is an engineered board that is made by splitting straw and formed by adding P-MDI adhesives and then hot compressing layers of straw in specific orientations.[2] Strand board can also be made from bagasse.


In 2005, Canadian production was 10,500,000 m2 (113,000,000 sq ft)(38" basis) of which 8,780,000 m2 (94,500,000 sq ft)( 3⁄8" basis) was exported, almost entirely to the United States.[3] In 2014, Romania became the largest OSB exporting country in Europe, with 28% of the exports going to Russia and 16% to Ukraine.[4]


OSB, closeup of corner

Adjustments to the manufacturing process can impart differences in thickness, panel size, strength, and rigidity. OSB panels have no internal gaps or voids, and are water-resistant, although they do require additional membranes to achieve impermeability to water and are not recommended for exterior use. The finished product has properties similar to plywood, but is uniform and cheaper.[5] When tested to failure, OSB has a greater load-bearing capacity than milled wood panels.[6] It has replaced plywood in many environments, especially the North American structural panel market.

While OSB does not have a continuous grain like a natural wood, it does have an axis along which its strength is greatest. This can be seen by observing the alignment of the surface wood chips.

All wood-based structural use panels can be cut and installed with the same ease and types of equipment used with solid wood.

The resins used to create OSB have raised questions regarding the potential for OSB to emit formaldehyde. Industry trade groups assert that formaldehyde emissions from North American OSB are "negligible or nonexistent".[7]

Some manufacturers treat the wood chips with various borate compounds which are toxic to termites, wood boring beetles, molds, and fungi, but not mammals in applied doses.


Four grades of OSB are defined in EN 300 in terms of their mechanical performance and relative resistance to moisture:[8]

  • OSB/1 – General purpose boards and boards for interior fitments (including furniture) for use in dry conditions
  • OSB/2 – Load-bearing boards for use in dry conditions
  • OSB/3 – Load-bearing boards for use in humid conditions
  • OSB/4 – Heavy-duty load-bearing boards for use in humid conditions


  1. ^ Technical information from the European Panel Federation
  2. ^ Han, Guangping, Cheng, Wanli, Manning, Mark, and Eloy, Pierre (2012). "Performance of zinc Borate Treated Oriented Structural Straw Board against Mold Fungi, Decay Fungi, and Termites - A preliminary trial" (PDF). BioResources 7 (3): 2986-2995. 
  3. ^ Review of Canadian Structural Panel Market
  4. ^ "Romania has become the largest OSB exporting country in the EU". Fordaq (Fordaq S.A.). 7 April 2014. 
  5. ^ Choosing Between Oriented Strandboard and Plywood
  6. ^ Experts Talk About Engineered Wood
  7. ^ Oriented Strand Board Frequently Asked Questions
  8. ^

External links

  • How it's made OSB on YouTube video showing OSB manufacturing process
  • Structural Board Association OSB resource library from the now defunct SBA
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.