Difference Between OSB and Plywood

When it comes to adding a roof sheathing or getting some new furniture built for your home, you have several wood types to choose from. One of the most preferred forms is what is known as engineered wood. The two prime types of wood used by contractors for home construction are plywood and OSB. While plywood boards are quire widely known, OSB is not that well-known.

Difference Between OSB and Plywood

Both plywood and OSB are similar in many ways. Both are indeed wood products but they differ in the way they are manufactured.

Basic Differences
The manufacturing of plywood begins by peeling of thin layers of wood from the surface of a log. These thin layers, known as veneers, are placed in a cross laminated fashion and subsequently glued together. This structure then undergoes metamorphosis into plywood as it is hot pressed. The adhesives, combined with the heat and pressure creates a plywood, that is made out of layers of wood, whose grains are perpendicular to each other. The strength of the plywood will depend on the kind of wood used for manufacturing and the number of layers hot pressed to create it. Plywood grades decide the thickness of a piece of plywood and its strength. There are many plywood sizes and types for you to choose from, according to your requirement.

OSB (Oriented Strand Board) is created in a similar manner as plywood, but the elements that are thermally compressed together are strands of wood, instead of layers. It is also known as waferboard or Sterling board. Just like the plywood layers, the strands that make the OSB are arranged in a cross fashion, before adhesive is applied and the whole structure is compressed together. The bonding material used for these boards is resin adhesive and wax in particular. They have a more rough exterior compared to plywood. They are used as wall or roof sheathing and find many other applications. Most importantly, it is manufactured from sustainable trees,

In terms of weight, an OSB piece mostly weighs more than a plywood piece of similar dimensions. Most importantly, it is more uniform internally compared to plywood. These boards can be comparable in strength to plywood. In terms of roof sheathing, you will find both materials to be comparable in strength. My research revealed only one minus point for OSB. It has higher water retention and therefore decays faster compared to plywood, if it is not sealed properly by a waterproofing sealant or paint.

So make sure that the OSB roofing you use, has waterproofing paint applied. In terms of stiffness, plywood has an edge over OSB. On the other hand, it is a fact that OSB panels can be considerably larger than plywood ones. A strength comparison will reveal that both materials are comparable in this aspect.

Cost
When it comes to cost, OSB tends to be slightly less costly, compared to plywood. If you make a per panel comparison of OSB and plywood panel costs, you will find that OSB costs around $5 lesser. This small difference can magnify into large savings in home construction, where a substantial volume of these engineered wood types are used.

The usage of non-formaldehyde based binders means that OSB is a more eco-friendly choice compared to plywood and hence, I would highly recommend that you opt for it. Using eco-friendly materials is a need of the day, as the impact of toxic construction materials on the environment can be ghastly. Otherwise, performance wise, OSB and plywood are both at par. Weigh the pros and cons carefully before opting between the two!