OSB Nailing Requirements
Contractors commonly use Oriented Strand Board (OSB) for wall and roof sheathing. OSB is manufactured from wood chips compressed with glue and formed into boards. Also used in other applications, OSB sometimes is used interchangeably with plywood. OSB is commonly marketed in 4-by-8 foot sheets and is available in a variety of thicknesses.
OSB installed over a 2-by-4 inch stud framework is generally either 5/16 or 3/8 of an inch thick. The common nailing pattern utilizes 6d nails placed every 6 inches along the edges of the OSB sheet, and every 12 inches into the studs in the interior of the sheet. Allow a gap of 1/8 inch around the OSB sheet and also between the OSB sheet and any other structural member.
OSB installed on roofs is commonly 3/8 of an inch thick when placed over rafters spaced 16 inches on center, and up to 1/2 inch thick on roofs where the rafters are spaced 24 inches on center. The nailing pattern is similar to the pattern used on walls. Place a 6d nail every 6 inches on the edges of the sheet with spacing of about 12 inches in the center of the sheet. The website Building a Garage suggests using 8d nails with 2-by-6 inch rafters. Place the nails with a framing nailer, if available, to save time during installation.
The website OSB Guide suggest extra nails may be necessary for projects built in areas prone to high wind or seismic activity. This would include parts of the U.S. prone to hurricanes or earthquakes. Spacing the nails closer, or using tie down clips installed according to manufacturer's instructions is commonly necessary in these high risk areas. Consult local building codes for any special nailing requirements or structural changes necessary in your region of the country.