Jack stud quiz

[Inspector Gadget]

Ran into this today, pitched a question to the inspectors in our shop, but felt it worth a discussion.

Story: client had intended on a larger door when the opening for his garage was constructed. The door he used is smaller. He used two jacks (only one was required) nailed together but separated from the king stud as shown here:



Question: Under NBC 2015, is this permissible? 'Splain why or why not.

 

[tmurray]

9.23.10.6.(2) requires double studs adjacent to the lintel, one (jack) running from the bottom plate to the underside of the lintel and one (king) running bottom plate to top plate. The double stud provided does not meet this requirement.

If they had KING>JACK>BLOCKING>Jack it would have been fine.

 

[ICE]

In what practical sense would this not be okay? There is room for a third stud.

 

[Inspector Gadget]

9.23.10.6.(2) requires double studs adjacent to the lintel, one (jack) running from the bottom plate to the underside of the lintel and one (king) running bottom plate to top plate. The double stud provided does not meet this requirement.

If they had KING>JACK>BLOCKING>Jack it would have been fine.

One of my lads made the same argument .... but there's no language in the above to state the two have to be adjacent to each other.

In what practical sense would this not be okay? There is room for a third stud.

Good perspective. And in this case, the span only required one jack and he's got two.

There is a way under Canadian Codes to require some corrective action, though...

 

[tmurray]

View attachment 11975

One of my lads made the same argument .... but there's no language in the above to state the two have to be adjacent to each other.

The argument I would make to that would be there is almost always a wall stud adjacent to an opening. If the code does not require that the king is adjacent to the jack, it does not require a king at all, since we could just make an argument that the next wall stud adjacent to the opening serves this purpose as well (nothing says that the second stud must be adjacent to the lintel either).

 

[Yankee Chronicler]

View attachment 11975

One of my lads made the same argument .... but there's no language in the above to state the two have to be adjacent to each other.




Good perspective. And in this case, the span only required one jack and he's got two.

There is a way under Canadian Codes to require some corrective action, though...

Not only that -- by spacing the jack studs out (in) from the king, the span of the header is reduced by 1-1/2 inches (or by 3 inches if both sides were framed the same way). IMHO, that makes the structure stronger.

 

[steveray]

Maybe not a "real" argument, but might not transfer the wind forces to the king stud as well...

 

[Inspector Gadget]

FYI, we approached this from the nailing table (T-9.23.3.4)



The nailing clause above notes that doubled studs must be attached to each other at 75cm (29+") intervals. In the case of the original photo, the client was asked to add either a third jack stud, or alternately, blocking at 29"/75cm intervals.