Plywood Grades

August 22, 2022

Channel Lumber is a leading supplier in plywood. There are many different types of plywood from structural to finish. There is a comprehensive system of grading for each plywood category. Let’s take a look at the many types of plywood, and define the grades. 

Grades of Pywood


  • ABX is factory sanded on the face and the back and ready for finish. It is a marine grade plywood that is perfect for applications where there is moisture. 
  • ACX has one face sanded, and the other face rough. This type of plywood has very specific applications. 


  • Marine-grade plywood has a somewhat misleading name in that it is not 100% waterproof. Marine is a high/good-quality plywood made with waterproof glue. Marine grade will work effectively for any plywood project, and is often used for projects where moisture is involved such at boats, docks, bathrooms, etc. 
  • Due to the high quality glue, marine plywood is the strongest and toughest grade of plywood. 


  • CDX and OSB panels are created with strands of wood mixed with resins. They are bonded under heat and pressure, and sealed for moisture resistance. The layered strands provide dimensional stability, as there are no grains or knots. 


  • Siding is primarily used for residential and non-residential exterior applications. This is a high-quality plywood manufactured to look good as well. The term "OC" refer on On Center, and describe the width between grooves on the plywood face. Grooves made every eight inches would be 8" OC. 


  • Sheathing is a structural plywood. It is strong, inexpensive and unfinished. It is not suitable for places that can be seen. 


  • A: sanded, smooth, paintable
  • B: Some repairs on the surface, usually football-shaped patches or wood filler
  • C: Can have small knows up to 1.5 inches
  • D: Can have knots of knot holes up to 2.5 inches

For more inormation about Channel Lumber and our plywood products, please contact us

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