Clip to Plywood

[dreber]

I would like a clip that I can use to transfer shear out of the roof diaphragm into the blocking without having to remove and replace the shingles above. The ply is 1/2" thick and the loads are really low. Is there anything rated for this application?

 

[jdgengineer]

Yes, see the Simpson Strong-Tie catalog or website.

https://www.strongtie.com/framingan...-a34-a35_productgroup_wcc/p/ltp4.ltp5.a34.a35

They have an option to install PH612l screws to the underside of the plywood with A35 clips (A35 Connection Type 5). These are proprietary short screws made by Simpson Strong-Tie. They used to specify SPAX screws prior to manufacturing their own screw, so would think either screw could be acceptable.

On a side note, I don't believe you can bend an A34/A35 clip. I would use an LS clip to the underside of the roof so you can have an angle other than 90. I don't believe they have testing with the LS clips with the short screws, but I think you could use engineering judgement for the connection or call Simpson Strong-Tie to see if they have any testing.

 

[jdgengineer]

On a side note, do you need the upper clip anyways? wouldn't their be plywood edge nailing to the blocking? Or is this new blocking? We typically only put in the clips to the underside of sheathing if we are putting in new interior shearwalls. At the exterior there should already be nailing between the plywood and the blocking.

 

[dreber]

Thanks for the lead on the PH612l screws! It seems that my google-foo may be lacking.

Regarding why to do it, this is a seismic retrofit to an existing structure and we have determined the existing edge nailing to be inadequate.

 

[Ron247]

I have no input on this post but I am curious what a "mystery screw" is. Never heard the term.

 

[dreber]

It was a bit of a joke on my part. Didn't know what kind of screw to specify.

 

[Ron247]

Geez, I thought you had found the Holy Grail of fasteners.