Slide 64 of 67
Notes:
- What should contractors do?
- When nailing sheathing, contractors should operate their nail guns within the manufacturer’s recommended pressure range
- Pressure should be: 90 to 120 psi, but many operate at 140 psi
- Install flush nailing attachments as required
- If a soft spot is hit, add another nail
- Inspectors should reject all nails driven below the surface of the sheathing
- Hand driven nails are rarely overdriven unless a soft spot in the framing member or blocking exists where the nail is installed.
- What other problems may come up when attaching the sheathing?
- When nails are installed too close to the sheathing edge, the shear wall will fail prematurely during seismic loading.
- The greater the edge distance, the better the sheathing connection will perform.
- The 1994 UBC only requires 3/8 inch
- To increase the strength of the connection, the minimum recommended edge distance for sheathing fasteners is ½ “.
- Edge distance is very important
- We know that the greater the edge distance, the better the sheathing connection will perform. An edge distance of 3” to 4” will be the strongest.
- Edge distance makes a big difference in how the shear wall will perform
- To get the greatest edge distance, center the nails in the framing members & blocking
- Centering the nail is easy to do on sill plates, sole plates and intermediate studs.
- Centering nails in the uppermost top plate frequently requires oversized panel sheets.
- Centering nails in framing members or blocking at adjoining panel edges is impossible.
- To make up for the inability to center the nails at adjoining panel edges, wider framing members and blocking are recommended at adjoining panel edges.
- For example: 8-foot walls
- Most 8-foot walls today are framed at a height of 8 ft-0¾ inch to allow for the gypsum wallboard on the ceiling.
- As a result, the common 8-foot sheet of wood structural panel sheathing does not span the full height of the wall.
- Frequently sheathing panels are installed vertically with one end flush to the bottom edge of the sill or sole plate and the other end centered on the uppermost top plate.
- This situation cannot easily be fixed by adding 3-inch plates.
- Thicker plates require longer framing nails that are not readily available and are more difficult to install.
- Solutions?
- Use oversized sheets.
- Both oriented strand board and plywood come in 9 foot and ten-foot lengths.
- When these lengths are used, shear transfer connections can be eliminated if nailing is provided to the floor or roof-framing members.
