How is osb

We're committed to clean, renewable options that meet environmental standards and coexist with sustainable forestry. We're focused on climate change solutions, creating sustainable homes for everyone, and supporting thriving rural communities. For more than a hundred years, Weyerhaeuser has been building and enhancing a reputation for responsible corporate citizenship.

We offer a range of exciting career opportunities for smart, talented people who are passionate about making a difference. A: Contract or Weyerhaeuser loggers come into a designated area to select and cut down trees that are ready to be harvested.

Branches are taken off and the trees are transported to an OSB mill. The knives spin as the wood goes through a ring, cutting the tree into individual strands with specific target width, thickness and length. Then, in a separate operation, they are passed over mesh screening to filter out different sizes. Larger strands are selected for the surface layers of OSB panels while smaller strands are used for the core layers.

A: The different strand sizes are blended in a rotating drum with resins and wax. Strands with resin and wax are then transported to the orienters. The orienters align the strands so that strands for the top and bottom surfaces of the panel go one way while the interior strands go in the opposite direction.

This adds stability to the panels. A: Before it goes into the press, the mat can be up to eight inches thick. Similar to plywood, OSB is often a go-to product and preferred for its many common uses. OSB can be fabricated into panel that are larger than plywood. Regardless of their differences, OSB and plywood are comparable products fabricated to meet the same standards of strength and structural performance.

Nonetheless OSB provides exceptional light-weight strength and durability. With the province of British Columbia recognized as a global leader in sustainable forest management, you can specify BC forest products with confidence. Connect with suppliers of OSB today. Wood products What is OSB? How is OSB made? The finished product is an engineered wood panel that shares many of the strength and performance characteristics of plywood.

Plywood is made from thin sheets of veneer layers of wood that are peeled from a spinning log that are cross-laminated and glued together with a hot press. Throughout the thickness of the panel, the grain of each layer is positioned perpendicular to the adjacent layer. The finished product is made from an odd number of layers so that a balance is maintained around its central access. Since it is made from whole layers of logs rather than small strands, plywood has a more consistent and less rough appearance than OSB.

In favor of OSB:. Get Started. To begin with, the composition of each material is different. Plywood is made from thin sheets of veneer that are cross-laminated and glued together with a hot-press. Imagine the raw log as a pencil being sharpened in a big pencil sharpener. The wood veneer is literally peeled from the log as it is spun.

Resulting veneers have pure tangential grain orientation, since the slicing follows the growth rings of the log. Throughout the thickness of the panel, the grain of each layer is positioned in a perpendicular direction to the adjacent layer. There is always an odd number of layers in plywood panels so that the panel is balanced around its central axis.

This strategy makes plywood stable and less likely to shrink, swell, cup or warp. Logs are ground into thin wood strands to produce oriented strandboard. Dried strands are mixed with wax and adhesive, formed into thick mats, and then hot-pressed into panels. Osb is different. The strands in osb are aligned. This structure mimics plywood. Waferboard, a weaker and less-stiff cousin of osb, is a homogeneous, random composition.

Osb is engineered to have strength and stiffness equivalent to plywood. Performance is similar in many ways, but there are differences in the service provided by osb and plywood. All wood products expand when they get wet.

When osb is exposed to wet conditions, it expands faster around the perimeter of the panel than it does in the middle. Swollen edges of osb panels can telegraph through thin coverings like asphalt roof shingles. The term ghost lines or roof ridging was coined to describe the effect of osb edge swelling under thin roof shingles. The Structural Board Association SBA , a trade association that represents osb manufacturers in North America, has issued a technical bulletin outlining a plan to prevent this phenomenon.

SBA correctly indicates that dry storage, proper installation, adequate roof ventilation and application of a warm-side vapor barrier will help prevent roof ridging. Irreversible edge swelling has been the biggest knock on osb. Manufacturers have done a good job of addressing this issue at the manufacturing facility and during transportation by coating panel edges.

The edges of cut sheets are seldom if ever treated in the field. Houses under construction get rained on.

And if you use osb in an area of very high humidity, like over an improperly vented attic or over a poorly constructed crawlspace, you are asking for trouble. Osb responds more slowly to changes in relative humidity and exposure to liquid water. It takes longer for water to soak osb and conversely, once water gets into osb it is very slow to leave.

The longer that water remains within osb the more likely it is to rot. Wood species has a significant impact. If osb is made from aspen or poplar, it gets a big fat zero with regard to natural decay resistance. Many of the western woods used to manufacture plywood at least have moderate decay resistance.

Rigid foam insulation was applied over osb and coated with a stucco-like covering. When the exterior foam boards were removed, wet, rotted, crumbling osb was exposed. Osb was slammed in the press.