Plywood & OSB Sheathing

[richburton]

What is the difference between OSB Sheathing and Structural OSB Sheathing? Just the stamp?

Thanks

 

[SLTA]

Check out "Panel Design Specification" by the APA.

http://www.apawood.org/level_b.cfm?content=pub_main

and type in the title. That gives some wonderful information.

My guess, out of context, is that "OSB Sheathing" refers to general OSB, while "Structural OSB Sheathing" refers to a specific grade.

Can you give more context for the two phrases?

 

[boo1]

Structural OSB must meet U.S. Department of Commerce Voluntary Performance Standard PS 2 “Performance Standard for Wood Based Structural Use Panels” and/or Canadian performance standard CSA O325 “Construction Sheathing”.
“ PS 2 specifies performance tests for concentrated and uniform static loads under wet and dry conditions. Impact tests are also specified as well as racking performance and fastener holding capability.”

 

[MiketheEngineer]

If both are rated as "APA" then their are definite design values that apply to each. And as you can buy APA rated OSB that is much cheaper and more available than the "Structural" grades - you see it quite often - when applicable.

As STLA stated - APAwood has all the info you need.

BTW - even though the new OSB's are moisture resistant - I always insist that it be kept dry - esp for floors.

 

[richburton]

The IBC Table 2304.7(1) lists a minimum roof panel thickness of 5/8" for roof trusses spaced at 24" O.C.
Simple enough.

But then the next Table 2304.7(3) allows for a thickness of only 7/16" for STRUCTURAL panels with a span rating of 24/16.

This would suggest that there are two types of panels.

The drawings call for OSB roof sheathing. No other information is given.

Then I must guess if they are going to use STRUCTURAL OSB with a minimum 24/16 span rating or the cheapest thing they can find at the lumber yard. I want to AVOID acid reflex when the problem is not identified until AFTER the roof sheathing is nailed to the rafters.

That's the issue I am trying to avoid by call for "STRUCTURAL OSB" if there is such a thing. I will simply include a note on the drawings, "OSB sheathing with a roof span rating of 24/16".

Thanks everyone for your help.

 

[OldPaperMaker]

richburton,
Structural I & Sheathing are just different grades of wood structural panels. They can be constructed from either OSB (Oriented Strand Board) or plywood.
If you look at the shearwall or diaphragm tables in the NDS or the IBC you will notice that Structural I and Sheathing grades have different allowable shear values. But, the values for the different grades are the same for both plywood or OSB.
I don't think that there is a grade called Structural OSB. It is probably a typo on the drawings.