Lag Screw Penetrations, minimum

[Everroux]

If a lag screw penetrates fully through the side member, is there still and 4D min penetration requirement for lateral load or is using the side member thickness for bearing okay (i.e. using 3/4" dia lag through 1-1/2" wood side member where 4D min would be 3" but the side member is only 1.5")

Thank you for any clarification on this

 

[jayrod12]

The minimum penetration is into the main member, the side member has no bearing on that. Most lag screws are smooth shank through the side member anyway.

 

[Everroux]

My bad. I meant the main member penetration in single shear as in attaching a ledger to band board.

 

[jayrod12]

Then no, you don't get to use the full value. You would have to base your design on a fastener that needs 1 1/2" minimum penetration or less. So 3/8" screws. Or through bolts.