Another Truss Blocking question

[JStructsteel]

I looked at the truss blocking thread some time ago, and it seems blocking or 'mini shear walls' are used when a heel is large (top chord to top plate distance). I have shown the plywood extend up at every other truss to a nailer between the top chord. Contractor is questioning it. The heel is about 21" tall. Would a better detail be just some diagonal 2x's from top chord to bottom chord, and let the truss connection take the shear? Its not a huge shear load.

The overhang is large, around 6'-10" so the load path is questionable, do I count on the soffit board to take shear back to the wall?

 

[jayrod12]

I've done soffit plywood when I was concerned about it. But then they complain about the blocking between trusses at the wall, and the fastening details for that plywood etc. If he doesn't like the plywood extensions, I'm ok with the 2x4 braces. I've done these fairly regularly.

 

[JStructsteel]

Thanks Jayrod12, 2x4 braces might be easier to install, cut, etc. Other thought was just plywood in the space between top and bottom chord, fastened to the vertical. There is a vertical at the bearing location on the truss.
I have a thought to call the truss manufacture and discuss, but I would think they are going to say 'no lateral load designed for'

 

[jayrod12]

A 20" tall heel will have no rollover stability. I would also be putting blocking between the trusses at the top and bottom for the braces to fasten to, as opposed to just relying on the plate connection between the vertical member and the chords.

 

[phamENG]

I agree that you need something in there. The 2x4 idea could work, but I'd be leery of the connections. The load path feels a bit more convoluted if you use the lumber bracing rather than the plywood. It's the contractor's job to pinch pennies where ever he can - I wouldn't change it unless he has a really compelling reason. "I haven't done this before" isn't usually compelling enough for me unless they have a good alternative in mind already.

 

[tonyiggy]

Not sure if your project is commercial or not The IRC Code has a few details. the plywood one is similar to what PhamENG suggested.