when to use OSB

[clare]

It's oriented flat. no strands renning surface to surface

[-MIKE-]

I can't tell if you guys are all blowing smoke up each other's rears or not. :-)

The "oriented" means, (as with plywood, where they cross hatch the grain pattern of each ply) the chips or shreds or whatever you want to call them in OSB, all have their grain oriented in the same direction on each layer they glue down, or "ply."

And it's not stronger in any direction.

[Neil Brooks]

Dunno' about that....

"Like waferboard, OSB is made of aspen-poplar strands, southern yellow pine or mixed hardwood species. However, the strands in the outer faces of OSB are normally oriented along the long axis of the panel thereby, like plywood, making it stronger along the long axis as compared to the narrow axis."

... or any number of other sources.

[-MIKE-]

I'm not going to argue your source, but when I saw it being made, the strands went north/south, east/west, every other layer.

Things may have changed since then, as they often do in anything dealing with evolving technology.

[J. Clarke]

It's an engineered product--the strands have whatever orientation give it the properties that the engineer wants it to have. If they went north/south, east/west every other layer, whichever orientation was on the faces that's the orientation of the stronger axis.

[Robatoy]

No there isn't. It is either waterproof or it isn't.

[Jack Stein]

I dunno, I always called it flake board or wafer board, and had the same question you do. I assume it's supposed to all go in one direction, but sure doesn't seem to do that, does it? Anyway, the stuff is pretty good for it's intended purposes. Of interest to me, someone who normally hates this stuff, I found it OK for doors on my TS bench... surprises the heck out of me. Even more surprising is in this very thread, someone else said/did the same thing... Also, I learned long long ago the stuff is more durable in weather than most people think, just keep it off the ground.

I think lots of people think of particle board, designed for indoor use like counter tops as so on, that stuff gets wet, it immediately swells and falls apart. If glue is not waterproof, it can't get wet. Wood is waterproof, so if you have a wood product, with waterproof glue, you should be OK. Of course, there is waterproof, and then there is waterproof...

[Hoosierpopi]

I've mainly used it for sheathing and covered it with 30# felt and siding. Have used it in the shop instead of Sheet Rock as it is better to fasten stuff to.

Just finished a small chicken coop made of the stuff (primed and painted inside and out!) and a re-enforcing beam some 18' long to tie the two walls of my shop and support the (metal - 5V Crimp) roof. There i ran a 2x10 bottom cord from wall to wall and cut and nailed and glued triangular sections to the rafters above it and itself, then ran another 2x10 nailed and glued and bolted to it like a sandwich and "sandwiched" the rafters above as well. I hope it will tie the tow walls together nicely and will try removing (it was a pole barn I expanded) one of the poles that I, now, feel is "in the way."

I think it's best not exposed to the weather as wet, it swells. Notwithstanding some of the comments I read replying to this post. At Lowes here in NC, its $5.65 a board and a bit cheaper at the local materials outlet.

[Hoosierpopi]

Why is it called Oriented when it's obvious it isn't?

"adjusted or located in relation to surroundings or circumstances;"

The chips are "oriented" (albeit randomly) with respect to on another. If they were all "oriented" in one direction, the resulting panels would not be as strong in any direction (and the panels would cost more thn solid hardwood owing to the time and effort it would take to so "orient" each little scrap one so all the grain was lined up).

[Nova]

The interior ply are oriented with each ply at a right angle to the next. It's only the outer two surfaces that are random.

[-MIKE-]

I was thinking that it would make sense to have it stronger in the lengthwise direction, since in its intended application, the width is supported by trusses and studs.

[-MIKE-]

you seen many industrial manufacturing machines and processes? They come up with incredibly fast ways to move, locate and place all kinds of things smaller and lighter than wood chips. I can't remember how they did it, but when I saw it, the chips all cam of a conveyor or belt or something, all pointing the same direction.

[else24]

I wasn't going to tell anybody but I think I have to get it off my chest. I needed a real workbench and I had to use what I had laying around, and that was some rough cut white oak two by fours and three OSB former shelf-boards boards. I laminated the three shelf boards together with yellow glue, then used the oak for the frame and to band the edges. I figured "This will last me a couple years and then I'll build a real one." Got it mostly sanded down, finished it will Waterlox and put a coat of Johnson's wax on the top. A friend gave me a couple of old quick release vises. Put some drop-down wheels on it so I could shove it around the shop when I had to. (That's pretty much required in that little shop.)

Almost five years later the top is still so flat that I can barely get a dollar bill underneath the middle of a straightedge across it the long way, the dog holes haven't crumbled, and it still serves as a clamping machine and assembly table. It's not especially long or wide but it's got a lot of mass.

I've decided to hold off > It's cheap, it's pretty tough, it's great for wall and roof

[J. Clarke]

If it's OSB intended for roof sheathing then that is in fact how it's made. If it's for wall sheathing then the strength might go the other way. There will be a marking on the faces that shows the direction of the strength axis.

[LDosser]

>> Have you seen many industrial manufacturing machines and processes?

[charlie]

>>>>> Have you seen many industrial manufacturing machines and processes?

wood magnets? try

[LDosser]

>>>>>>>> Have you seen many industrial manufacturing machines and processes?

Nothing in that about magnets. :(

[-MIKE-]

I was thinking roof or floor. There isn't really much strength need for wall sheathing, other than what it takes to help square the wall, and that's in a different direction altogether. :-)

There are home builders who will use rigid polystyrene sheets for sheathing, and just use a half sheet of ply/OSB on the corners. please.

If you're a thief, why waste your time with a door, when all you need is a cordless reciprocating saw to cut a man sized hole in the freakin wall?

[Martin H. Eastburn]

Jack I think you get indoor use strand with deck board and roof and siding mixed up.

There is outdoor water proof glue. It makes for a heavier board and is more expensive. Some builders cheap out.

A big builder in San Jose area was caught a few years after he completed a housing tract. I think insurance paid and he continues to pay high insurance.

The other one on rood decking - use stainless staples. If you use normal steel they will rust out and shingles will blow or fall off.

Mart> LDosser wrote:

[Jack Stein]

"Randomly oriented"

Ya gotta love it:-)

Almost as good as deafening silence, or cruel kindness...