SPDWS wood structural panel sheathing requirements

[PI31415]

In TABLE 4.3A of the SDPWS (2015 edition), wood structural panels have a higher unit shear capacity than regular plywood siding. However, I am not seeing what constitutes a wood structural panel. APA Structural I or APA rated sheathing stamps are easy enough to read, but I cannot tell if the following meets the requirements.

PS1-22 EXT AC 15/32 CAT. Grp. 4 0 0.453 IN
MEETS UNDERLAYMENT REQUIREMENTS

I specified Structural I or APA 24/16 rated sheathing, but the contractor wants to use plywood stamped with the info above.
My question is: what constitutes a wood structural panel? (What standards does it need to meet?)

C4.3.3 (in the 2015 SDPWS) somewhat gets into this, but it does not explicitly state where the line is drawn, or I am not understanding it.

Thank you all for your thoughts.

 

[RWW0002]

My understanding is that Structural I should be stamped along with the other information

When to Use Structural I Sheathing - APA – The Engineered Wood Association

www.apawood.org

 

[jerseyshore]

Great graphic above. Rated sheathing and Structural I will be labeled as such.

The APA website that RWW also linked has endless plywood info to answer all of your questions.

If it doesn't say "rated" then I don't approve it as such.

 

[XR250]

I avoid specifying S1 panels due to the difficulty in contractors finding them.

 

[PI31415]

I appreciate all the feedback.

@RWW0002 I read through a lot of the APA resources and they are immensely helpful understanding for Structural I and APA rated plywood. Thank you!

@XR250 I also avoid Structural I when possible. That's why I gave the option for APA 24/16 rated sheathing as an alternative.

From my understanding of the APA, the APA rated plywood meets the specs of PS1 & PS2 as well as additional APA specs. However, I am wondering if this is the minimum requirements to consider plywood a wood structural panel and treat it as such for unit shear capacities (SDPWS table 4.3A) or if plywood that meets PS1-22 (but not APA rated req's) could also be considered a wood structural panel sufficient for the shear loads given in the aforementioned table.

I know the plywood already partially installed by the contractor does not meet the requirements specified, but I am wondering if it needs to be replaced or if it meets the minimum requirements to be considered WSP and therefore can work for the shear walls.

 

[lexpatrie]

Having seen Structural I on several plans (one multi story residential and one high end single family OUTSIDE California) I have yet to see the stamp on the supplied product, eight to ten years after it was built, so I would suggest engineers outside California avoid using this material if at all possible, and if they do, the FEET must be held to the fire (via ON SITE verification). That would be my recommendation.

I'd be concerned something that "meets underlayment requirements" isn't really meant for use as a wall panel. It's possible, but my curiosity is raised. That sounds like it's rated as floor sheathing and roof sheathing, not strictly intended for (highly stressed shear) walls.

Maybe it's just me, but Structural I (capitol "I") sheathing isnt something most engineers would just randomly slap into their general notes as some kind of "screw it i don't care" specification, meaning the structure needs it.

AWC has a technical support desk, I'd start there for your documentation in the file.

Slight wifi situation.

Anyway, if the contractor is not meeting the specifications, the job (at minimum) should receive a credit for the less expensive material, the switch, if it is a switch, needs to be accepted by the EOR as an RFI as the Structural I in a shear wall is higher capacity versus generic wall sheathing (sheathing grade).