Originally Posted By: ccoombs This post was automatically imported from our archived forum.
I would suggest you call APA at 253-620-7400. They can typically answer your question on the first call. Their web site is www.apawood.org. But I find calling is faster.
Originally Posted By: John Green This post was automatically imported from our archived forum.
“This side down” applies to when it’s used as subflooring. That side should be facing down, against the joists. When used as wall sheathing, that side should be against the studs.
Originally Posted By: srowe This post was automatically imported from our archived forum.
does the OSB have to be side down not how to put the side down.
I was just curious if anyone knows if the manufacturers put "This Side Down" for roof sheathing for safety reasons or because there is a structural reason for it.
One side is clearly rougher (safer to walk on) than than the other.
Originally Posted By: John Green This post was automatically imported from our archived forum.
Sorry, I misunderstood your question. Since you inquired about sheathing, I assumed the OSB was on the walls, and you were thinking “this side down” applied to the vertical orientation.
The indicated down-side is the rough side, correct? I'm thinking that by having the rough side against the studs, you end up with better shear strength. I seriously doubt that there is any structural implication either way. But checking with the manufacturer is of course the best bet. Let us know what you find.
Originally Posted By: ccoombs This post was automatically imported from our archived forum.
Shawn
I just called APA. They provide approval for most wood structural panel (OSB and Plywood). They stated that they do not have special requirements for a specific side up or down. However, they stated that some manufactures like to have the rough side up for safety issues.
Originally Posted By: mkober This post was automatically imported from our archived forum.
“This Side Down” is stamped there for a definite SAFETY reason. The stamp is on the smooth side, which will mean the rough side is up on roof rafters or trusses. I’ve heard of workers sliding off of roofs because of uninformed or careless roof sheathing installers putting the smooth side up. OSB manufacturers don’t like ambulance-chasing lawyers any more than we do.
Originally Posted By: rray This post was automatically imported from our archived forum.
- provide a safe, secure, nonslip surface for roofing installers wearing rubber-soled boots, according to comprehensive testing conducted by Forintek Canada Corp., a major Canadian independent research firm.
Tests were conducted under both wet and dry climatic conditions using OSB panels from a variety of SBA-member mills.
Bold text mine. So I suspect, as stated earlier, that it is safety and that the "this side down" side is the smooth side.
Originally Posted By: sbonilla This post was automatically imported from our archived forum.
As previously stated, building inspectors want to be able to look up and see the stamps, the other reason is there is a special coating on the non stamped side that is suppose to be water proof sealer.
Originally Posted By: Scott Drake This post was automatically imported from our archived forum.
Feel Free to look at the www.tecotested.com website for questions related to structural panel products.
Reversing the "This Side Down" is not a structural issue, it however can be a problem if the inspector can not see the stamps after installation.
The rough side is an industry "requirement" and is only there to prevent some of the potential for a slick panel. The slope and weather conditions play a much bigger role than the rough surface. North American producers are the only ones that make a rough surface, so if you see any European or S. American panels used they will not have a rough surface.