How much does decking cost for a roof?
Short answer. Roof decking is sold in 4 by 8 foot panels of OSB or plywood; OSB is usually the less expensive of the two, and thicker panels cost more. Panel prices move with the lumber market, so check a current local price, and remember that on a reroof the installed cost per sheet, including removal of the old sheathing, matters more than the panel price, since many reroofs need only a few sheets.
The material choices
- OSB (oriented strand board). Wood strands pressed with resin. Common on newer Georgia homes and usually cheaper.
- Plywood. Cross-laminated veneers. Typically costs more and many roofers like how it holds nails and handles moisture.
- Radiant barrier sheathing. OSB with a foil face toward the attic. Costs more and can reduce attic heat gain in Georgia summers when installed with an air space.
Thickness
Required thickness depends on rafter or truss spacing and the roof load, set by the residential code tables. Newer homes with trusses 24 inches apart often have 7/16-inch OSB; older homes may have 1/2-inch plywood or wide boards. Replacement sheets should match the existing thickness so the roof surface stays flat.
What drives the price
- The lumber market, which can swing panel prices noticeably within a year.
- Thickness and grade.
- Installation: cutting out old sheathing, fastening new panels and disposal.
- How many sheets your roof needs. Area divided by 32 square feet gives the count for a full redeck.
A note on the word
"Decking" also means outdoor deck boards. On a roof, it is the sheathing nailed to the rafters that the shingles are fastened to. See OSB vs plywood roof decking and attic heat and shingles.