Floor Attic For Storage Question

[GDay]

Am sure there will be a variety of opinions to this question. My floor plan has an option for a Game-room above the garage.My house does not have the Game-room. The builder used the same 2x10 joists over the garage at 24” OC. I plan to spray Insulation to the top of the joists and floor most of it for Holiday Decorations and other things. The floored area will be 16’x25’. I plan on using 19/32 OSB. I am thinking I can get by with using Sheathing clips on the unsupported ends of the OSB sheets. I have seen 30 men and materials on roofs around here and that is the system used.
I just thought I would see what the reaction is to going with Sheathing clips as opposed to using wood framing for support.
Gary

I stated the wrong size area to be floored. It is 8’x25’ down the center.

[srv52761]

.... The builder used the same 2x10 joists over the garage at 24” OC. ......The floored area will be 16’x25’. I plan on using 19/32 OSB. I am thinking I can get by with using Sheathing clips on the unsupported ends of the OSB sheets. I have seen 30 men and materials on roofs around here and that is the system used.
I just thought I would see what the reaction is to going with Sheathing clips as opposed to using wood framing for support.
Gary

I will assume you have looked into code. With that said...
1. 2x10 at 24" oc seems just a tad small for a 16' span. Not much, but a little.
2. 19/32" seems thin for 24" centers

3. At 24" centers, run them perpendicular to the joists and use osb designed for flooring... tongue and groove... and consider gluing the tongue.
Take a look at the Advantech osb flooring system.

Don't skimp on materials. An extra couple hundred dollars now is cheap insurance for a satisfactory result later.

[Snipe Hunter]

Sheathing clips aren't intended for a live load. They're intended to keep roof sheathing from buckling. Roof sheathing buckles due to many factors, live loads aren't one of them so the H clips aren't designed for it. They're just stamped sheet-metal or extruded aluminum. Why not just use tongue and groove subflooring intended for this use?? Personally, I think using 19/32 without the support of the tongue and groove is a recipe for disaster.

If I remember correctly, 15' is the max for live spans using #1 2x10 at 24" on center.

If I were doing this... I'd put in a support beam to make the span "legal" for a live load. To do it and meet code, you'll need engineered drawings (at least here) and ether adequate footers or a way to distribute the load over the existing garage floor slab. Again though, you'll need the engineered drawings and calculations to pull permits.

All that being said...

If I were going to forgo a proper support beam, I'd use a 23/32 sub-floor material called AdvanTech. It's made by Huber. Lowes (Not Home Depot) sells it in 23/32 for about $20 a sheet. It's a very high density and very flat tongue and groove OSB.  You'll see the difference between it and generic T&G OSB as soon as you look at it, feel it and lift it. Much less deflection, much more water resistant, much better shape retention (stays flat). It's very hard so you might want to use a nail gun for install. If you don't have a nail gun, consider using construction screws like these "partial thread" Spax 2-1/2" #8  Here
Make sure you use the "partial thread" with the flat head to pull the sub-floor tight to the joists. I'm guessing you could find a larger qty. box at a better price online somewhere.

[Wild Turkey]

When you see guys walking on a roof I'll bet they spend most of their time along the supported parts and avoid the edges that are unsupported.

That plus the American "pack rat" syndrome would make me err on the side of caution -- since you're going to the trouble of making a floor I'd make it heavy enough to take a load at some time in the unforeseen future.


19/32 OSB might hold up but I'd sure put some 2x4's between joists at least at the joints if not every 24". Easy to get to before the insulation is sprayed and cheap insurance.

[GDay]

I made a real goof on this thread. The useable space is only 8’x25’ down the center of the garage. The tongue and groove might be worth the cost. The 2x4 blocking on 19/32 is also a good option. Thanks for all the help and waking me up.
Gary

[rwe2156]

I made a real goof on this thread. The useable space is only 8’x25’ down the center of the garage. The tongue and groove might be worth the cost. The 2x4 blocking on 19/32 is also a good option. Thanks for all the help and waking me up.
Gary

If that was retrofitted for a potential floor, the 24" centers surprise me, 2x10 or not.

If its just storage, what you're wanting to do is probably OK, afterall you're walking around on it like a floor, right?

If there is a definite plans to convert to usuable space (or have the potential), I would bite the bullet now & use 3/4" T/G ply.  Rather than blocking I would use 2x4's layed down flat on 16" centers under the ply. You're only losing 1 1/2" of height.

[GDay]

If that was retrofitted for a potential floor, the 24" centers surprise me, 2x10 or not.

If its just storage, what you're wanting to do is probably OK, afterall you're walking around on it like a floor, right?

If there is a definite plans to convert to usuable space (or have the potential), I would bite the bullet now & use 3/4" T/G ply.  Rather than blocking I would use 2x4's layed down flat on 16" centers under the ply.  You're only losing 1 1/2" of height.

This will never be used for anything except Decorations and old photos and slides my wife wants to keep.

[Snipe Hunter]

The tongue and groove might be worth the cost.

imho... T&G is always worth the cost for subflooring. Can't remember the last time I saw anything different.

[srv52761]

.... The useable space is only 8’x25’ down the center of the garage. 

even if.... 
If the joist are running the entire 16' width then the deflection, especially in that 8'x25' part down the middle will be the same.  (It would be better if you had said we are only going to be storing stuff very close to the sidewalls).

Wrt just pictures.  I took thousands of pictures of my kids growing up.  My wife has saved them all (despite me spending the first month of retirement scanning about half of them).  Some of those tubs weigh more than a bag of readymix.  

Never say never.

[GDay]

even if.... 
If the joist are running the entire 16' width then the deflection, especially in that 8'x25' part down the middle will be the same.  (It would be better if you had said we are only going to be storing stuff very close to the sidewalls).

Wrt just pictures.  I took thousands of pictures of my kids growing up.  My wife has saved them all (despite me spending the first month of retirement scanning about half of them).  Some of those tubs weigh more than a bag of readymix.  

Never say never.

The plan is to store mostly against the sidewalls as u mentioned. We need to be able to get to it from the middle. I am looking at all the options suggested here. I really appreciate the comments.