How to Install OSB Roof Sheathing
Oriented strand board, commonly referred to as OSB, is a manufactured sheet of chipped or flaked wood pieces, layered under pressure, then bonded with a resin adhesive. These sheets or panels are engineered to meet the same structural strength and applications as standard plywood panels. Although OSB is a lighter, more economical substitute for plywood roof sheathing, the installation uses the same methods of cutting and attachment. Does this Spark an idea?
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Things You'll Need
- Tape measure
- Marker
- Chalk line
- Circular saw
- Hammer
- 8d sinker or ring-shank nails
Instructions
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1
Mark the layout line for the first row of OSB roof sheathing. Measure vertically up the top surface of the last rafter at each end of the roof plane with a tape measure and place a mark at 4 feet from the outer face of the fascia. For gable roofs, mark the measurement on both of the outer rafters, referred to as "barge rafters." For hip-type roofs, mark the first jack rafter that exceeds 4 feet long. Connect the two marks with a horizontal chalk line.
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2
Lay an OSB sheet onto the rafters. Align the top edge with the chalked line and shift the leading edge to align with the centerline of the nearest rafter. Allow the excess to extend over the gable end or hip rafter to be cut later. Secure the OSB sheet in place with nails spaced 12 inches apart and 2 to 3 inches from the edges at each rafter. This will be the standard nailing pattern for all of the OSB sheets.
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3
Place the next sheet of OSB onto the rafters, with the end tight to the previous sheet and the top edge aligned with the chalked line. Verify that the leading end reaches the centerline of a rafter or cut it to length with a circular saw, as needed. Secure the OSB sheet in place with the standard nailing.
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4
Repeat Step 3 to complete the first row of OSB roof sheathing. You can allow the OSB sheathing at the end to extend over the edge of the gable or hip rafter to be cut later or trim it to length to install.
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5
Start the next horizontal row of OSB sheathing by laying the sheet in place at the starting end above the first row. Shifting the sheet horizontally to offset the end joints in the row a minimum of 32 inches from the end joints of the first row. This is a typical offset used between all adjacent rows of OSB sheathing. Cut the starting end flush with the gable or hip rafter, as needed, or allow it to extend it over to be cut later.
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6
Place the next OSB onto the rafters, with end tight to the previous sheet. Verify that the leading end reaches the centerline of a rafter or cut it to length, as needed. Secure the OSB sheet in place with the standard nailing.
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7
Repeat Steps 5 and 6 to complete the row of OSB sheathing and complete the roof section coverage. Continue to offset the end joints in adjacent rows by a minimum of 32 inches.
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8
Cut the excess OSB sheathing extending over the end of the gable or hip rafters, if necessary. Snap a chalk line aligned with the gable or hip rafter to mark a cut line for the extended ends of the sheathing and use a circular saw to cut the OSB sheathing along the cutline.
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Tips & Warnings
You can increase the sheer strength of the OSB sheathing panel. Add a bead of construction adhesive to each rafter before installing the sheet.
