Another how to fix it thread

[TRAK.Structural]

So a contractor I do work with from time to time called me out to look at something. The inspector failed his floor framing because he over-notched the joists due to an existing 2x4 ledger strip (dark colored wood) rather than the typical 2x2 strip (it's a renovation job). So now I'm trying to rationalize if/how I can make this work. My first thought is to just have them put hangers on each joist and nail them to the 2x4 ledger strip, but this 2x4 is only face mounted to the rim/band behind it with no vertical support from below. Ideally I want most of the load being transferred directly to the band which is vertically supported by the foundation wall instead of to the 2x4 and then to the band through nail shear. Am I over thinking this? What does the group think?

 

[EngDM]

You learn something new every day - this is why I visit this forum
Going to start speccing structural air screws in my future designs

Just FYI, you should consider adding the "N" designation to your callup for that premium nitrogen air. The nitrogen is colder so it causes the screw to shrink, and then expand once it is shot into the sheathing for even more grip. So now you have another mechanism aside from just the moisture really gripping the nails.

 

[ChorasDen]

Now I have a real problem. I am constantly picturing a free-body diagram of a nail into air. I have 14.7 psi air pressure applied to the exposed surface of a 16d nail. If we can find a reference with the coefficient of friction between steel and air, we might be onto something. Its like a song you can't get out of your head. Until we can solve this, I am not tackling the structural air screw, much more difficult.

Gosh, I need a nap.

maybe this is only a west coast concern, but what exactly is the developed diaphragm capacity of a 23/32" subfloor panel nailed to air?

 

[gte447f]

I wouldn't worry about relying on the ledger strip to transfer load back to the rim joist, since this is analogous to a ledger strip on floor girder and has been standard practice for decades to century(ies) and is still permitted by the code. Use 3-16d commons or per joist or more if necessary, since you will be running numbers. Just for the heck of it, I would spec a long screw to reinforce the crack that they have already conveniently started. There is a document floating around somewhere that I remember seeing that outlines how to assess this situation for reinforcement purposes. Then I would look for a short joist hanger that would work only fastened to the 2x4 ledger strip.