Tongue And Groove Poplar Core CDX Pine Plywood Plywood For Construction

CDX plywood is used under shingles and roofing felt, on walls (just behind the siding and insulation), and as a sub floor. I've used it for creating rough shelving in a basement or garage, and it works fairly well for those kinds of projects where function is more important than appearance. CDX refers to the grade of the sheet, one side is "C" while other Is "D" meaning it will have imperfections and knots visible with football shaped plugs. "X" refers to the glue used which is stronger and may be exposed to weathering for short periods during repairs.