Slide 63 of 67
INSTALL NAILS FLUSH TO THE SHEATHING
- The 1994 UBC stated that the nail should “not fracture the surface of the sheathing”.
- The 1997 UBC has clarified the language to state that the “head or crown of the nail is flush with the surface of the sheathing.”
- Nails installed with their heads resting on but not into the sheathing can cause problems for roofing and other finishes.
- Nails should be driven so that the top of the nail is flush and not above the surface of the sheathing.
- What happens during an earthquake?
- Nails will try to pull through the thickness of wood structural panel sheathing during an earthquake
- For this reason, it is important that nails should be driven flush with the surface of the sheathing and not overdriven and that they be placed correctly
- Overdriven nails:
- Reduce the shear wall strength by effectively reducing the thickness of the sheathing.
- At panel edges, overdriven nails allow easier nail punch-through.
- At intermediate studs, overdriven nails allow easier panel buckling.
- Why are nails overdriven?
- Excessive air pressure in the nail gun
- Too long of a driving pin on the nail gun.
- When the spacing and framing member thickness allow, nails should be added to replace any overdriven nails.