Plywood panels are rated for three end uses: sheathing for roofs, floors and walls, single-layer flooring and exterior siding. Panels that are performance rated carry a stamp indicating the panel’s performance rating, performance category, maximum span ratings, and bond classification. Performance rated plywood is frequently specified by architects and engineers to ensure that building materials meet or exceed design requirements and building codes. Exposure 1 panels are intended to resist the effects of moisture on structural performance due to short-term weather exposure that panels may be subjected to on a job site.īond classification is not indicative of a panel’s resistance to mold, fungal decay or physical breakdown. Exterior panels are capable of withstanding repeated wetting and redrying or long-term exposure to weather. Panels are manufactured in two adhesive bond classifications – Exterior or Exposure 1. In short, performance category is the nominal thickness of the panel. Frequently used softwood species such as Southern Yellow Pine and Douglas Fir from the northwestern United States and western Canada are Group 1 species. Wood species are divided into five groups according to strength and stiffness, Group 1 containing the strongest/stiffest and Group 5 the least strong/stiff. The specific type used contributes to its overall strength and stability. There are many species of wood used in the manufacture of plywood. For example, an “A-C” panel, will have a face with few, if any, repairs or splits while the back will have many repairs. The grade reflects the veneer quality relative to its natural growth characteristics and the number and size of repairs and imperfections allowed during the manufacturing process. Gradeįace and back veneers are graded in descending order of quality, A, B, C-plugged, C, and D. Here’s what you need to know about each attribute. Plywood is specified according to the grade of the face and back veneers, the species of wood used to make the panel, performance category, bond classification, and performance rating. In fact, plywood that has fewer plies will be weaker than plywood with more plies, even if the two plywoods have the same thickness. When more ply is used, the board is stronger and thicker. The “ply” in plywood refers to a layer of veneer that is used to create the different thicknesses of the plywood. Manufactured from thin sheets of cross-laminated veneer and bonded under heat and pressure with strong adhesives, plywood panels have superior dimensional stability, an excellent strength-to-weight ratio and can be highly resistant to impacts, chemicals, and changes in environmental temperature and humidity. Plywood is one of the most recognized and trusted wood building products. Understanding the various grades and material qualities of plywood will ensure that you stock the types of plywood your customers need. Plywood is manufactured across a wide variety of grades and thicknesses. Plywood is necessary for a broad range of commercial, residential, and DIY projects, making it a high demand item throughout the year.
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