Lag Bolt Edge Distance

[SteelPE]

I know NDS has a requirement for lag bolts placed near the edge of a wood member. I believe the minimum distance is 1.5xdiameter of the bolt.

I need install a metal plate on the outside of a house that has a built up wood column (3-2x's). The lag need to go into the 1 1/2" side of the built up section (3- 1 1/2" members for a total width of 4 1/2"). Does this minimum edge distance apply to the individual members, or does it apply to the overall wood section.

 

[Colostruct]

The edge distance is to each piece. I don't do anything larger than 5/16" diameter into the center of a 2 x member. Usually, I will defer to the Simpson catalogue to see what their tested edge distances are and use one of their engineered screws (such as SDS series)

This is a detail, IMO, that is fraught with potential for failure in installation. It is very difficult to convince framers that they really do need to hit the center of a stud. Depending on what sort of loads are carried, I might not rely on this detail except for a secondary member of little importance. Keep in mind that if you are going through sheathing, there may be additional reductions in capacity.

 

[SJBombero]

Unless the members of the built-up column were built similar to a glulam, I would say that the minimum edge distance applies to each individual member. The obvious problem with considering it as a single member is the case in which the lag screw falls on a seam. Even though it has 1-1/2" edge distance, no one would consider that structurally sound.