Sheathing Orientation and Associated Shear Capacity

[JohnnyB_]

Hello -

I have always assumed that the shear strength of an OSB sheathing panel is greater when installed horizontal (8' direction perpendicular to studs) than vertical (8' direction parallel to studs). I have been reviewing table 4.3A of the SDPWS 2021 and it doesn't state which direction the panels should be installed in order to meet the stated shear capacities. This leads me to believe that regardless of which way the shear panel is installed vertical or horizontal it will still provide the given shear capacities assuming the the other design variables are followed.

I would love to get some opinions on directing the contractor to install the panels vertical or horizontal.

Thank you!

 

[kissymoose]

It doesn't matter for shear strength. It can matter for perpendicular loads.

 

[JohnnyB_]

Thanks kissy

 

[phamENG]

Correct for shear walls. Not for diaphragms. Sheathing layout and orientation does matter for diaphragms.

 

[JohnnyB_]

Thanks pham

 

[DoubleStud]

If I am not mistaken, it does not matter for wall because you always block the edge so you can nail all edge (6" o.c. or smaller). UNFORTUNATELY, this is not always the case. Framers miss this a lot and not put blocking at the seams. So technically if that happens, horizontal has more value if the plywood is too short to go to the top of wall.

 

[JLSE]

An old engineer once told me that the staggered edges used in a vertical layout provides better racking resistance. I always figured, if it matters for diaphragm shear.. it matters for shearwall shear. But NDS T 4.3A footnote 2 states the values for shear can be increased...... if ..... the panel is applied with long direction across stud. APA has some good resources.