Roof sheathing is a complicated process, and it is best done with a team of 2 or 3 people working together. The best product to use for roof sheathing is plywood particle board or wafer-board, as they’re both relatively low cost items and are fairly easy to work with.
Check your local building codes to determine which thickness is acceptable to use in your area, and if you can, round up an air compressor with a nail gun – it’ll make the work go much, much faster.
Getting Started on the Roof
1) Before you do anything, double-check the rafter tails to ensure they’re sitting on a straight line – if not, you’re going to have to correct it, lest you look up from the ground and see crooked rafters. Yes, it will be very visible. Draw a chalk line across the tails, and then saw off any excess wood, creating a straight line.
2) When you’re ready to put the sheets up, start from the eaves and work your way to the peak, or roof ridge. The last course at the top may need to be cut away, if the roof wasn’t built according to 4-foot increments, but this isn’t a cause for great concern.
What you do need to keep in mind is that the sheathing at the eaves line must be perpendicular to the roof rafters – this is even more important than making sure they’re flush, since you can add a piece of tapered sheathing later to fill in the eave. Having them perpendicular means the sheet will meet at the center of the rafters, so that you can put the nails in.
Nailing Things Down
3) Local code often requires nails in the roof sheathing placed every 6 inches on the edge, but check with your code to be sure. If this is the case, you probably need a nail every 12 inches in the sheet field, so use a piece of chalk to draw a line across the wood sheets as a guide for nailing.
4) Make sure you stagger the joints of each sheathing course, just like you would for bricking or tiling. Cut a panel in half, and use the half sheets to start each alternate course of sheathing. You can also purchase metal clips that are specifically made to add stability to these splice areas where the wood sheeting comes together.
5) As you work up toward the roof peak, continually check your alignment and end support. One way to ensure your safety on the project is to nail down a 2 x 4 board, sometimes referred to as a “toe board”, across the lower panel of sheathing. This will give you something to brace against while you lay down the next courses of sheathing.
Sheathing with Patience
6) Only try to sheath one slope of the roof at a time – don’t bounce back and forth to either side, trying to get both done at once. When you get to the top ridge, rip off any excess wood and draw yourself a chalk line down any of the edges that need to be trimmed. If you’d rather cut before nailing these ones, that works as well, but take your time.
7) Finally, use a circular saw at the necessary angle and depth, and cut along the edge on your chalk line. This gets rid of an excess, useless overhang, and helps give the roof that clean look.
8) Done on one side? Great: now repeat the process on the other side or on any smaller sloped areas of the roof.