It is time to ship your product and you need a crate. After reaching out to a few vendors you realize companies use different wood products. The most common wood products are OSB and plywood for shipping crates.
There are distinct differences between OSB and plywood. Which is stronger? Which holds up to moisture? Which material is more cost effective? Let’s dive into the pros and cons of each to determine what is right for transporting your product.
What is OSB?
Oriented Strand Board is a type of engineered wood product similar to particle board. It is formed by combining water-resistant adhesives with scrap wood chips, the mixture is arranged in layers and bonded together using heat and pressure. Depending on the manufacturer and use, it can be treated with fire-retardant, water-resistant, and insect repelling chemicals.
What is plywood?
Plywood is an engineered product made of sheets of thin wood veneer. The wood sheets are peeled away from a spinning log creating long thin sheets. The sheets are then dried and stacked with the grain arranged in alternating directions. This manufacturing technique is called cross-graining, it minimizes shrinkage and expansion while providing a very consistent and strong product that can withstand significant stress and weight. The layers of sheets combined with glue are sent through a hot pressed to cure the glue and bond the wood together.
Strength
Both items are manufactured wood products, one consists of wood chips pressed together the other is wood sheets pressed together.
There is debate from various industries on which option is stronger, but they all agree the usage makes the difference.
Plywood’s cross grain technique always consists of an odd number of layers in ply panels, this allows it to balance around its central axis. The laminated structure of plywood distributes the impact of loads over a larger area, this reduces tensile stress. Additionally, the cross-graining of plywood allows it to maintain its structural integrity and thus stable and strong under changes of temperature and moisture (more on this in the next section). Meaning it’s less likely to shrink, swell, cup, or warp.
Plywood is 10% stiffer than OSB according the NACHI, and added stiffness is beneficial during shipping, plywood bites the screws and nails more efficiently and the rigidity increases the protection for the contents inside of the plywood crate.
Moisture Resistance
In transit your crate will likely encounter rain and snow. Which option is better at handling the elements and keeping your product safe?
OSB manufacturers claim their newer technology including the press machines and chemical concoctions create a higher quality OSB that is just a strong as plywood in dry conditions. This is great for building permanent structures because the wood is covered with plastic or waterproof material or used inside for subflooring. For a crate that is transported on a flat bed or sitting in a shipping yard, wet conditions are almost a guarantee.
When compared side by side. Plywood is quicker to absorb moisture, but dries faster, returning close to its original integrity. OSB absorbs slower but holds water which gives the moisture time to warp the board. According to Pathnet.org, an online resource for homeowners and buyers, the edges of water saturated OSB can expand up to 15%, specifically on cut edges. Once the board swells it does not return to its original integrity. This will compromise the structure of the crate built with OSB. Nails and screws will start to pull away, gaps might form on the corners, exposing your product.
Budget friendly
On average OSB is 10-30% less expensive than plywood boards. Since OSB is comprised of wood chips and not full pieces of lumber it’s more cost effective. Therefore many contractors use it for building homes, it lowers material cost and since the OSB isn’t exposed to the elements it creates a sturdy structure.
However, when transporting a crate, the material savings of an OSB crate often do not outweigh the cost of potential damages to your product if the OSB becomes wet and structurally weak.
If your product is only traveling a short distance (30-50 miles) and is not extremely fragile or expensive, OSB or a heavy duty corrugate will get the job done; however, plywood gives our customers confidence their product will arrive safely.
Conclusion
Over the 30 years Cratek has been in business and manufacturing wooden crates, we’ve received frequent calls from businesses who cut corners by ordering an OSB crate and during transit their product was damaged. Although, OSB has many valuable uses overall it is not the ideal material for cross-country or trans-continental crating and shipping.
References:
Jasuja, Nikhilesh, and Pooja Sehgal. “OSB vs. Plywood.” Diffen, https://www.diffen.com/difference/OSB_vs_Plywood.
Fisette, Paul. (2005) “Choosing between OSB and Plywood.” University of Massachusetts Amherst, https://bct.eco.umass.edu/publications/articles/choosing-between-oriented-strandboard-and-plywood/.
Gromicko, Nick. “OSB vs. Plywood.” International Association of Certified Home Inspectors, https://www.nachi.org/osb-plywood.htm
“OSB vs. Plywood.” Public-Private Partnership for Advancing Housing Technology, pathnet.org/sp_id_17336.html#
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