Exterior Sheathing Calculator

How to Use This Calculator

1. 1Calculate total wall area (perimeter × wall height).
2. 2Subtract rough opening areas for doors and windows.
3. 3Click Calculate.

About This Material

Exterior wall sheathing is the structural panel layer applied over the wall studs before housewrap and siding. Its primary function is providing racking (shear) resistance against lateral forces from wind and earthquakes, while also serving as a nail base for siding attachment. The standard material is 7/16-inch or 1/2-inch OSB, which costs $15 to $30 per 4x8 sheet. CDX plywood offers better moisture performance at a higher price ($25 to $45 per sheet). Panels are installed vertically (long dimension running floor to ceiling) for maximum racking resistance and are nailed to the studs following a specific nail schedule — typically 8d nails at 6 inches on center along panel edges and 12 inches in the field. Some builders in hot-humid climates prefer structural insulated panels or rigid foam sheathing with metal bracing for better moisture management, though these require engineering approval. Sheathing is required on all exterior walls in most wind and seismic zones.

Installation Tips

• •Orient panels vertically (long edge vertical) for best racking resistance.
• •Leave 1/8" gaps at all panel edges.
• •Nail 6" OC on panel edges, 12" OC in the field.
• •Use 8d nails or staples per code.

Common Mistakes to Avoid

• ⚠Running panels horizontally — reduces shear resistance.
• ⚠Skipping the expansion gap — panels buckle and bow.
• ⚠Under-nailing — racking resistance depends on nail schedule.

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