Types of Canadian plywoods commonly used in construction/industrial applications are Douglas Fir Plywood (DFP), Canadian Softwood Plywood (CSP), Aspen/Poplar Plywood (Poplar). DFP is produced to the manufacturing standard CSA O121 Douglas Fir Plywood where front and back faces are Douglas Fir. Plywood containing other selected Canadian softwood species in face and back plies is labelled CSP and is manufactured toCSA O151 Canadian Softwood Plywood. These standards specify minimum requirements for sizes, grades, specialty panels, manufacturing tolerances and glue bond quality.
Both Douglas Fir and Canadian Softwood Plywoods are manufactured in several grades. The grades are dependent upon the appearance and the quality of the veneers used for the outer plies. The three qualities of veneer are designated by the letter A (best appearance), B, and C (the lowest appearance grade). The manufacturer, using these veneer grades in various combinations, can produce panels suitable for a variety of uses as shown in Table 1.
Sheathing grades which are not specified for appearance usually carry the grade stamp on one of the faces, and the grades such as Good Two Sides carry the stamp on the edge so that it does not mar appearance.
|Table 1: Plywood – Standard Grades|
|Grade||Governing Canadian Standard||Individual Veneer Grades||Characteristics||Typical Applications|
|GoodTwo Sides (G2S)||CSA O121(DFP)||A||C||A||Sanded. Best appearance both faces. May contain neat wood patches, inlays or synthetic patching material.||Used where appearances of both sides is important. Furniture, cabinet doors, partitions, shelving, and concrete formwork.|
|GoodOne Side(G1S)||CSA O121(DFP)||A||C||C||Sanded. Best appearance one side only. May contain neat wood patches, inlays or synthetic patching material.||Used where appearance on one side is important. Furniture, cabinet doors, partitions, shelving, and concrete formwork.|
|Select-Tight Face(SEL TF)||CSA O121(DFP)orCSA O151(CSP)||B1||C||C||Unsanded. Permissible face openings filled.May be Cleaned and Sized (C&S).||Underlayment, combined subfloor and underlayment, sheathing, and hoarding.|
|Select(SEL)||CSA O121(DFP)orCSA O151(CSP)or Poplar||B||C||C||Unsanded. Uniform surface with minor open splits. May be Cleaned and Sized (C&S).||Underlayment, combined subfloor and underlayment, sheathing, hoarding and packaging.|
|Sheathing(SHG)||CSA O121(DFP)orCSA O151(CSP)||C||C||C||Unsanded. Face may contain limited size knots and other defects.||Roof, wall, and floor sheathing.|
|Medium Density Overlaid(MDO)||CSA O121(DFP)orCSA O151(CSP)or Poplar||Smooth, resin-fibre overlaid surface.Best paint base.||Siding, soffits, paneling, built-in fitments, signs, or any use requiring a superior paint surface.|
|Notes:1.openings filled with wood patches or putty.2.All gradesbonded with waterproof phenolic glue.3.Veneer grades: A: highest appearance grade; B: medium appearance grade; and C: appearance grade.|
Veneer Grade Characteristics
|Grade A||Grade B||Grade C|