OSB vs Plywood for Roof Decking

Strength, Moisture Resistance & Cost Compared

OSB and CDX plywood are both code-approved for roof sheathing, but they behave differently. OSB is 10-15% cheaper, more dimensionally consistent, and made from sustainable fast-growth wood; plywood is more moisture-tolerant (dries faster), holds nails better, and weighs slightly less. Both meet APA span ratings for 24-inch rafter spacing at 7/16 OSB or 15/32 plywood. In humid coastal climates, plywood is the safer long-term choice; everywhere else, OSB is the modern standard.