{{short description|Engineered wood particle board}} [[Image:Oriented strand board at Courtabœuf 2011.jpg|thumb|OSB is easily identifiable by its characteristic wood strands.]] '''Oriented strand board''' ('''OSB''') is a type of [[engineered wood]], formed by adding [[adhesive]]s to layers of [[wood]] strands (flakes) laid in specific orientations and compressing them. It was invented by Armin Elmendorf in California in 1963.<ref>{{cite web |url=https://depatisnet.dpma.de/DepatisNet/depatisnet?action=pdf&docid=US000003164511A |title=Dokument US000003164511A |format=PDF |website=DEPATISnet |publisher=Deutsches Patent- und Markenamt |access-date=2 May 2016 |archive-date=13 December 2023 |archive-url=https://web.archive.org/web/20231213033059/https://depatisnet.dpma.de/DepatisNet/depatisnet?action=pdf&docid=US000003164511A |url-status=live }}</ref> OSB may have a rough and [[variegation|variegated]] surface with the individual strips of around {{convert|2.5|×|15|cm|in|1|abbr=in}}, lying unevenly across each other, and is produced in a variety of types and thicknesses.
Oriented strand board is sometimes confused with ''chipboard'', a synonym for [[particle board]], whose "chips" are of a size that a lay person would likely describe as "particles".
==Uses== [[Image:LSFosb05.jpg|thumb|OSB is frequently used in light [[steel frame]] house construction.]]
OSB's mechanical properties make it suitable for load-bearing applications in [[construction]].<ref name="osb-info1">{{cite web |url=http://www.osb-info.org/technical.html |title=Technical Information |publisher=Osb-info.org |access-date=2016-05-02 |archive-date=2016-05-09 |archive-url=https://web.archive.org/web/20160509234841/http://www.osb-info.org/technical.html |url-status=dead }}</ref> In North America, it is more popular than [[plywood]], commanding 66% of the structural panel market in 2016.<ref>{{cite news|last1=Marotte|first1=Bertrand|title=Toronto's Norbord riding the rising wave of OSB sales|url=https://beta.theglobeandmail.com/report-on-business/forest-products-firm-norbord-riding-the-rising-wave-of-osb-sales/article30985989/|access-date=20 September 2017|work=[[The Globe and Mail]]|date=19 July 2016|archive-date=12 August 2019|archive-url=https://web.archive.org/web/20190812215615/https://beta.theglobeandmail.com/report-on-business/forest-products-firm-norbord-riding-the-rising-wave-of-osb-sales/article30985989/|url-status=live}}</ref> The most common uses are as [[Siding (construction)|sheathing]] in walls, flooring, and roof decking. For exterior walls, panels are available with a [[Radiant barrier|radiant-barrier]] layer laminated to one side; this eases installation and increases energy performance of the [[building envelope]]. OSB is also used in [[furniture]] production.
==Manufacturing== [[Image:OSB production.jpg|thumb|OSB in production before pressing in a thermal press]]
Oriented strand board is manufactured in wide mats from cross-oriented layers of thin, rectangular wooden strips [[compression (physical)|compressed]] and bonded together with [[wax]] and synthetic [[resin]] [[adhesive]]s.
The adhesive resins types used include: [[urea-formaldehyde]] (OSB type 1, nonstructural, nonwaterproof); [[isocyanate]]-based glue (or [[PMDI]] poly-methylene diphenyl diisocyanate–based) in inner regions with [[melamine-urea-formaldehyde]] or [[phenol formaldehyde resin]] glues at surface (OSB type 2, structural, water resistant on face); phenol formaldehyde resin throughout (OSB types 3 and 4, structural, for use in damp and outside environments).<ref>{{citation | url = https://sciencing.com/types-glue-used-osb-8615640.html | first = Tony | last = Oldhand | title = Types of Glue Used in OSB | date = 25 Apr 2017 | work = sciencing.com | access-date = 1 August 2018 | archive-date = 1 August 2018 | archive-url = https://web.archive.org/web/20180801190656/https://sciencing.com/types-glue-used-osb-8615640.html | url-status = live }}</ref>
The layers are created by shredding the wood into strips, which are sifted and then oriented on a belt or [[wire-mesh caul]] (a heated, ventilated support) and coated with the resin.<ref>{{cite book |last1=Koch |first1=Peter |title=Utilization of hardwoods growing on southern pine sites |date=1985 |publisher=U.S. Dept. of Agriculture, Forest Service |location=Washington, DC |oclc=13459178 |page=2423}}</ref> The layers thus built up are transferred to a forming line and cross-oriented so that strips on the external layers are aligned to the panel's strength axis, while the internal layers are perpendicular.<ref>{{cite book |last1=Hedges |first1=Keith E. |title=Architectural Graphic Standards |date=2017 |publisher=[[Wiley (publisher)|Wiley]] |location=Hoboken, NJ |isbn= 9781119312512 |chapter=Oriented Strand Board|edition=12}}</ref> The number of layers placed is determined partly by the thickness of the panel, and is limited by the equipment used. Individual layers can also vary in thickness to give different finished panel thicknesses; typically, a {{convert|15|cm|1|abbr=on|adj=on}} layer will produce a {{convert|15|mm|2|abbr=on|adj=on}} panel thickness{{cn|date=April 2016}}. The mat is placed in a thermal press to compress the flakes and bond them by heat activation and curing of the resin. 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. <!-- uncited, out of date The largest production facilities can make over {{convert|1000000|sqft|m2|abbr=on}} of OSB per day.{{Citation needed|date=April 2008}} -->
==Related products==
'''Waferboard''' belongs to the subset of reconstituted wood panel products called [[flakeboard]]s.<ref>{{cite web |title=AP-42: 10.6.1 Waferboard/Oriented Strandboard Manufacturing |url=http://www.epa.gov/ttnchie1/ap42/ch10/final/c10s06-1.pdf |url-status=dead |archive-url=https://web.archive.org/web/20111216021325/http://www.epa.gov/ttnchie1/ap42/ch10/final/c10s06-1.pdf |archive-date=2011-12-16 |access-date=2013-10-08 |publisher=epa.gov}}</ref> It is a structural material made from rectangular wood flakes of controlled length and thickness bonded together with waterproof [[phenolic resin]] under extreme heat and pressure. The layers of flakes are not oriented, which makes it easier to manufacture. Waferboard is used as a material to build cheap furniture. This type of furniture is usually laminated.
Materials other than wood have been used to produce products similar to OSB. [[Oriented structural straw board]] is an engineered board made by splitting straw and formed by adding P-MDI adhesives and then hot compressing layers of straw in specific orientations.<ref>{{cite journal |url=http://www.ncsu.edu/bioresources/BioRes_07/BioRes_07_3_2986_Han_CME_Zn_Borate_OS_Straw_Bd_Termite_Trial_2741.pdf |journal=BioResources |title=Performance of zinc Borate Treated Oriented Structural Straw Board against Mold Fungi, Decay Fungi, and Termites - A preliminary trial |author=Han, Guangping, Cheng, Wanli, Manning, Mark, and Eloy, Pierre |date=2012 |volume=7 |number=3 |pages=2986–2995 |doi=10.15376/biores.7.3.2986-2995 |archive-date=2015-12-25 |access-date=2015-09-23 |archive-url=https://web.archive.org/web/20151225074421/https://www.ncsu.edu/bioresources/BioRes_07/BioRes_07_3_2986_Han_CME_Zn_Borate_OS_Straw_Bd_Termite_Trial_2741.pdf |url-status=live }}</ref> Strand board can also be made from [[bagasse]].
==Production== In 2005, Canadian production was {{convert|10.5|e6m2|e6sqft|abbr=off}} ({{convert|3/8|in|mm|abbr=on|disp=or}} basis) of which {{convert|8.78|e6m2|e6sqft|abbr=off}} were exported, almost entirely to the United States.<ref>{{cite web |url=http://www.fordaq.com/fordaq/news/Canadian_structural_panel_market_13586.html |title=Review of the Canadian structural panel market |date=24 August 2006 |publisher=Fordaq.com |access-date=2016-05-02 |archive-date=2016-04-06 |archive-url=https://web.archive.org/web/20160406190234/http://www.fordaq.com/fordaq/news/Canadian_structural_panel_market_13586.html |url-status=live }}</ref> In 2014, [[Romania]] became the largest OSB-exporting country in Europe, with 28% of the exports going to [[Russia]] and 16% to [[Ukraine]].<ref name="Fordaq">{{Cite news |work = Fordaq |publisher = Fordaq S.A. |title = Romania has become the largest OSB exporting country in the EU |url = http://www.fordaq.com/fordaq/news/Romania_OSB_exports_EGGER_Kronospan_36635.html |date = 7 April 2014 |archive-date = 3 June 2016 |access-date = 1 August 2014 |archive-url = https://web.archive.org/web/20160603054915/http://www.fordaq.com/fordaq/news/Romania_OSB_exports_EGGER_Kronospan_36635.html |url-status = live }}</ref>
==Properties== [[Image:OSB-Platte.jpg|thumb|OSB, closeup of corner]]
Adjustments to the manufacturing process can affect thickness, panel size, [[Strength of materials|strength]], and [[Stiffness|rigidity]]. OSB panels have no internal gaps or voids, and can be water-resistant, although they do require additional [[Artificial membrane|membrane]]s 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.<ref>{{cite web |url=http://www.umass.edu/bmatwt/publications/articles/osb_vs_plywood.html |title=UMass Amherst: Building and Construction Technology » Choosing Between Oriented Strandboard and Plywood |publisher=Umass.edu |date=2015-09-04 |access-date=2016-05-02 |archive-date=2009-04-10 |archive-url=https://web.archive.org/web/20090410144456/http://www.umass.edu/bmatwt/publications/articles/osb_vs_plywood.html |url-status=live }}</ref> When tested to failure, OSB has a greater load-bearing capacity than milled wood panels.<ref>{{cite web |author=Chaya Kurtz |url=http://www.networx.com/article/experts-talk-about-engineered-wood |title=Experts Talk About Engineered Wood - Articles |publisher=Networx.com |date=2010-05-12 |access-date=2016-05-02 |archive-date=2016-06-01 |archive-url=https://web.archive.org/web/20160601213122/http://www.networx.com/article/experts-talk-about-engineered-wood |url-status=live }}</ref> It has replaced plywood in many environments, especially the North American structural panel market.
All wood-based structural use panels can be cut and installed with the same types of equipment as for solid wood.
=== Health and safety === The resins used to create OSB have raised questions about their emission of [[volatile organic compounds]] such as [[formaldehyde]],<ref>{{cite journal |author1-link=George Mantanis |last1=Mantanis |first1=George I. |last2=Athanassiadou |first2=Eleftheria Th. |last3=Barbu |first3=Marius C. |last4=Wijnendaele |first4=Kris |date=2018-03-15 |title=Adhesive systems used in the European particleboard, MDF and OSB industries |journal=Wood Material Science & Engineering |volume=13 |issue=2 |pages=104–116 |doi=10.1080/17480272.2017.1396622 |issn=1748-0272}}</ref> although industry trade groups assert that formaldehyde emissions from North American OSB are "negligible or nonexistent".<ref>{{cite web |title=Oriented Strand Board Educational Bulletin, Frequently Asked Questions |url=http://osbguide.tecotested.com/pdfs/en/el814.pdf |url-status=dead |archive-url=https://web.archive.org/web/20160304041656/http://osbguide.tecotested.com/pdfs/en/el814.pdf |archive-date=4 March 2016 |access-date=2 May 2016 |website=OSBGuide |publisher=TECOTested.com}}</ref> [[Urea-formaldehyde resin|Urea-formaldehyde]] is more toxic and should be avoided in home use. [[Phenol formaldehyde resin|Phenol-formaldehyde]] products are considered to be relatively hazard free. Some newer types of OSB, so-called "new-generation" panels, use [[isocyanate resin]]s that contain no formaldehyde and are considered nonvolatile when cured.<ref>{{cite web|last1=MacLeod|first1=Ian|title=I'm concerned about toxic offgassing from OSB subflooring and roofing|url=http://www.greenhomeguide.com/askapro/question/i-m-concerned-about-toxic-offgassing-from-osb-subflooring-and-roofing-are-safer-products-available|website=Green home guide|access-date=2015-11-14|archive-date=2016-06-05|archive-url=https://web.archive.org/web/20160605121604/http://www.greenhomeguide.com/askapro/question/i-m-concerned-about-toxic-offgassing-from-osb-subflooring-and-roofing-are-safer-products-available|url-status=dead}}</ref>
Some manufacturers treat the wood chips with various [[borate]] compounds that are toxic to [[termite]]s, wood-boring [[beetle]]s, [[Mold (fungus)|mold]]s, and [[fungi]], but not [[mammal]]s in applied doses.
In 2024, a hotel in [[Dublin]], Ireland, lost its [[fire safety certificate]] after an inspection found fault with the composition of OSB in its flooring and walls.<ref>{{cite news |title=Operators of Dublin hotel with fire safety issues seeking order for €4.2m remedial works |url=https://www.irishtimes.com/business/2025/11/03/dublin-hotel-potential-fire-danger-after-original-construction-issues-discovered/ |access-date=3 November 2025 |newspaper=The Irish Times |date=3 November 2025 |location=Dublin |language=en |archive-date=3 November 2025 |archive-url=https://web.archive.org/web/20251103204932/https://www.irishtimes.com/business/2025/11/03/dublin-hotel-potential-fire-danger-after-original-construction-issues-discovered/ |url-status=live }}</ref>
===Types=== Five grades of OSB are defined in EN 300 in terms of their mechanical performance and relative resistance to moisture:<ref name="osb-info1"/> * OSB/0 – No added formaldehyde * 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
==See also== * [[Medium-density fibreboard]], engineered board with much smaller flakes
==References== {{Reflist}}
{{Wood products}} {{Woodworking}} {{DEFAULTSORT:Oriented Strand Board}} [[Category:Composite materials]] [[Category:Engineered wood]]