doubling up 7/16 osb

[richard7]

framing office in shop roughly 13x17 . 2x10 floor joist on 16 center for 2nd floor . I have a whole lot of 7/16 osb wanted your opinion on doubling it up for the flooring will be used for storage space. Run it both ways with glue between ? what do you all think thanks

 

[ItsNemo]

framing office in shop roughly 13x17 . 2x10 floor joist on 16 center for 2nd floor . I have a whole lot of 7/16 osb wanted your opinion on doubling it up for the flooring will be used for storage space. Run it both ways with glue between ? what do you all think thanks

Doesn't matter what we think, this is entirely down to the building inspector and local laws.

 

[PassnThru]

So the office would be on the second floor? If so, I would personally just put blocking in the joists if you want it to be less bouncy. No need to double it up. It would be fine structurally with one layer but would deflect some without the extra blocking. Laminating two sheets together would be harder than extra blocking.

 

[richard7]

1st floor office 2nd floor is storage

 

[PassnThru]

OK - so you're building an office and want to put a floor on the top for storage. Same answer - add some blocking to the ceiling joists in the office and the 7/16 will be firm.

 

[richard7]

Plan was nail down 1st layer then nail down second layer running the sheets the opposite direction with maybe glue between sheets.posting here cause i wanted your opinion not the counties . I am pretty sure 3/4 osb would be recommended but would 7/16 x 2 perform just as well or even better? I have atleast 80 sheets of it would like to put it to use.

 

[richard7]

Thanks passnthru,

 

[Dissident]

There is an installation document from Huber for their Advantech system. Just search the google for '2-Layer Subfloor with AdvanTech.' Even though their stuff is tongue and groove, if it were me, I would use this method. Like it says, I don't think adhesive is needed between the two layers, only on the first. The part about having it dried in though before the second layer is most important. I used Advantech 1-1/8" and I'm happy with it, although I had to put more screws in after I got the roof on because it swelled from a bit too much rain.

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[Dissident]

Here is a link:

https://www.huberwood.com/uploads/d...oring-Technical-Tip-Subflooring-AdvanTech.pdf

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[ddawg16]

When I was doing my 2-story addition, the architect had me using 1 1/8" T&G plywood. WTF?

So glad I did. I used 2x12's on 16" OC floor joists, with that thick plywood, walking on my second floor is about par to walking on concrete.

On the second floor of my garage....I had a brain fart and ran the subfloor the wrong way (parallel to the joists). So, I ran a second layer perpendicular.... glad I did. Nice and stiff.

 

[Michigan Mike]

As long as the building inspector doesn't have a problem with it I would do it. I wouldn't run it different direction. Stagger the joints. Start with a two foot piece not a four foot. and stagger the end joints.

 

[theoldwizard1]

1st floor office 2nd floor is storage

So the office would be on the second floor? If so, I would personally just put blocking in the joists if you want it to be less bouncy. No need to double it up. It would be fine structurally with one layer but would deflect some without the extra blocking. Laminating two sheets together would be harder than extra blocking.

Concur ! Blocking, especially at the seams, will make a huge amount of difference. It will still be "bouncy" but it will be fine.

 

[The Cobbler]

doubtful it would pass , assuming its being inspected

 

[richard7]

Here is a link:

https://www.huberwood.com/uploads/d...oring-Technical-Tip-Subflooring-AdvanTech.pdf

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good read i wonder if their product is osb material?

 

[strutaeng]

1st floor office 2nd floor is storage

So the second story is like an attic or walk-out-attic?

If it's an attic I don't think the Building Code actually requires any floor decking. 7/16" OSB is nice. And if you are doubling 2 layers, well, that's extra nice.

Just don't call it "storage" because building official may confuse it for industrial storage and then will require 125 psf live load, then you'll be screwed. Not sure if it matters or not.

Good luck.

 

[Dissident]

good read i wonder if their product is osb material?

Yes, it is OSB. Only difference is the T&G and probably some proprietary glue.

The IRC has 7/16 @ 16oc material in their subfloor table so I don't see any problem with doing it that way.

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[like2wheel]

But that stuff costs $25/ sheet these days.
Wouldn't it be better to sell it & buy something that won't be 2x the labor + 5x the glue?

 

[James-W]

But that stuff costs $25/ sheet these days.
Wouldn't it be better to sell it & buy something that won't be 2x the labor + 5x the glue?

That is an interesting idea, and it would be nice if he could, but who would he sell it to? He will need to find a buyer and what price should he sell it for? Also, will a buyer want to buy all 80 sheets, or just a few sheets?

Selling the OSB may work out OK, but in my opinion, I think if he can use it for flooring that is the best route to take.

 

[matt_i]

I would do it as you suggest, place squiggly patterns or "X" patterns of construction adhesive between the layers. I don't think its necessary to alternate the directions, just overlap the seams.

My situation: The previous owner who built the first part of my shop put 1/2" ply on 24" centers in the attic section. Walkable but a spongy mess. I realized I had two choices, tear out the 1/2" or do as you suggested and add a 2nd layer. ~10 years later I still believe it was a good decision.

 

[mmb617]

If I didn't have to worry about satisfying an inspector I'd do it. I don't think running the second layer the opposite way adds anything as long as you stagger the joints but I would go with the glue as it would make me feel better. In my mind gluing them together would be close to using one piece twice as thick.

 

[MadMechMaster]

Sounds like a mezzanine inside a pole building. Using what you have already is probably fine. Especially with sheet prices today.

 

[38Chevy454]

A single layer of 7/16 OSB will be a little bouncy on 16 inch centers. Doubling that will be very nice and solid feel. OSB doesn't really have directional properties, so changing direction won't have any significant effect. Ensuring seams do not overlap is going to make a difference. IMHO, gluing between layers is probably good idea, although more for squeaking than an outright strength benefit.

Use what you have, save the money.

 

[CTyankee]

As long as you're not going to store engine blocks up there, one layer should be fine. I'd just screw it down. IMO any gain by adding another layer will be offset by the added weight of it.

 

[Kev442]

I've done it.
No way I would do only one layer, I've seen way too many things punch through 7/16's OSB like it isn't even there over the years.

 

[mepstein]

I just purchased 25 sheets of 7/16 osb. I also had some older sheets from 2005 that I had laying around. What a difference. The old stuff feels like wood. The new stuff like compressed cardboard. If I tip the new stuff on it's corner, the corner breaks off.

If you already have the material, I would double it up.

 

[duneslider]

unless you do a full spread of glue it won't do much good gluing it. Run the same direction but stagger joints both directions. blocking will help it feel more solid but won't increase capacity at all and where this is just storage why bother and waste the time.

If you care about potential squeaks glue to the joists, or screw it all down.

For just storage I think your plan is great.

 

[richard7]

Thanks everyone for the advise.Running 2 layers same direction, staggering joints both directions sounds like the best advise.