Is this OSB exposed? Is it OK?

[randynavarro]

I found this OSB used as a substrate for the exterior deck.

Is it allowed to be "exposed" like this?

I can't find anything to the contrary.

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[hausdok]

Sure, why not? It's used for roof decks all the time. There's not a whole lot of difference between a roof deck and that balcony deck, no?

OT - OF!!!

M.

[randynavarro]

I've found something . . .

And yes Mike, more specifically, I was thinking there's no difference between the application in my picture and an enclosed, ventilated crawl space.

HOWEVER, per APA's "Finishing Exposure 1 OSB Sheathing" bulletin, it's not recommended that OSB be used as underlayment for elastomeric coatings. I wasn't expecting that.

In all the APA docs I reviewed, there's very little reference to exterior applications for OSB. When discussing OSB on the outside, the only examples ever mentioned are using the product to enclose soffits; not decks, or stairs, or the underside of wall bump-outs (think gas fireplaces.)

[RobC]

Regular 3/4" plywood is the recommended sheathing for vinyl decking.

There could be a compatibility issue with adhesives and OSB.

http://www.duradek.com/_customelements/ ... 009web.pdf

[kurt]

Cramer was describing some OSB decking that was exposed after a hurricane blew through and took out the structure. The stuff laid exposed to Florida sun and weather for a couple years with only minor swelling at the seams.

The stuff is pretty tough.

I'm still waiting to see my first elastomeric deck coating......is that stuff popular out there?

[hausdok]

I'm still waiting to see my first elastomeric deck coating......is that stuff popular out there?

Like fleas on a stray dog.

OT - OF!!!

M.

[randynavarro]

Cramer was describing some OSB decking that was exposed after a hurricane blew through and took out the structure. The stuff laid exposed to Florida sun and weather for a couple years with only minor swelling at the seams.

The stuff is pretty tough.

I'm still waiting to see my first elastomeric deck coating......is that stuff popular out there?

Yea. I agree. OSB today is not the stuff our daddies were building with.

I'm planning on using it for an addition on my place I'm beginning shortyl (I've always used traditional ply.)

However, it's the edge swelling that's a concern. The product won't "fail" but if you're applying an elastomeric coating, I suppose the swelling could rupture the coating.

In fact, I noticed the seams starting to ghost through on yesterday's job. After all the research I could do in a reasonable amount of time yesterday, I concluded the OSB isn't gonna work on those decks and that it needs to get fixed somehow.

[hausdok]

I noticed the seams starting to ghost through on yesterday's job. After all the research I could do in a reasonable amount of time yesterday, I concluded the OSB isn't gonna work on those decks and that it needs to get fixed somehow.

I know a guy who did these for more than ten years; he may or may not agree that OSB doesn't perform well under this stuff. I think his experience is probably more telling than anything else we could find in print. I'll see if I can't get him to weigh in on this thread.

ONE TEAM - ONE FIGHT!!!

Mike