How to Plywood Sheath an Exterior Wall

Plywood sheathing adds stability to the walls of a wood frame house. Since plywood has come into use, the construction of wind braces within a wood frame is no longer necessary. The laminated material also serves as a vapor barrier to a building, especially when it is covered with a moisture-proof plastic material. As a result most wood frame buildings built today use plywood sheathing as an exterior building material.

Things You'll Need

• Saw horses
• Tape measure
• Chalk line
• 20-ounce hammer
• 8-penny galvanized nails
• Framing square
• Exterior grade 1/2- to 3/4-inch plywood

Instructions

Installing the Plywood

1. Begin installation on the back side of the building (the rear of the building is likely to have fewer openings, making it the easiest side to complete). Chalk a line from one end of the building to the other to establish the bottom edge of the plywood. Be certain to follow the builder's instructions, as to what height the first row of plywood is placed and use pressure-treated plywood if required.

2. Place the first sheet of plywood at the bottom of the back wall so the edge of the plywood is located at the midpoint of the wood frame wall. If the wall is framed correctly, both vertical edges of this piece of plywood will fall dead center on a vertical stud.

3. Place the second piece on the other side of the wall's midpoint, so the second piece's vertical edge abuts the first piece. This means the first two sheets of plywood will be joined at the center or midpoint of the wall.

4. Place additional sheets of plywood, working away from the center in both directions, until reaching each end of the building. The bottom edge of each sheet of plywood must be flush with the chalk line. If there are no door or low-level window openings, you can run the first row across the length of the wall with the only cut being the one made at the end of the row. For doors and windows, cuts will have to be made in the appropriate locations.

5. Install the next row of plywood above the first row. The first sheet is positioned in the center of the wall but is staggered four feet, provided the stud frame wall has 16- or 24-inch on-center framing. This stagger will position the edges of this sheet line up above the midpoint of the sheet located below it. This creates rows of plywood that are offset from each other by four feet.

6. Continue this row in both directions to the far edge of the building and cut the last piece so it is flush with the outside of the building. Continue upward with alternating rows until you reach the top of the wall. The top row will have to be ripped lengthwise so that it can fit underneath the roof.

7. Repeat these steps for each side of the house.

Tips & Warnings

• Make sure corners are covered with plywood.

• When nailing plywood, place the nails every 6 to 10 inches in a vertical row along the stud. Always have someone assist you with the installation task.

• Don't leave plywood exposed to the elements when finished. Cover the plywood with plastic as soon as it is put up.

References

• Stucco Guru: Plywood Sheathing
• Dan Vandervort's Hometips: Sheathing Exterior Walls