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Plywood or OSB

MR.Gunk

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Jan 29, 2014
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2
My opinion. Use a minimum 5/8" osb with the foil on it. And use the clips between the sheets. I wish I would have.

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ForceFed70

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Apr 27, 2010
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BC, Canada
Yes Plywood is certainly better. It's also much more expensive.

My thinking is that if there is a failure/problem the OSB won't be at the root of the problem - it'll be something else. Water intrusion, failure to use the right thickness OSB, etc.

Roof leaking, structural failure, etc. When this happens - plywood or not you still have a problem and you still have damage that needs to be repaired. Worried about screws pulling out due to high wind - use thicker OSB.

People need to stop thinking in such simple terms as "Plywood vs OSB". You need to understand what your needs are and use the appropriate materials. In almost all cases, going with a thicker OSB vs plywood is still cheaper and will produce the same or better results.

I laugh at the "I only use plywood" meatheads. Avoid these builders. Your better off to use the correct OSB and use the saved money elsewhere in your build if you're looking for a high quality build. Buy better windows and doors, thicker slab, etc - spend your money on something that makes sense rather than bragging rights. Very few of us can afford "money is no object" type of builds.
 

finn

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The UP, God's country
ForceFed70 has it right.

Engineering is about specifying the right materials for the job, it is not about picking the most expensive material to build with.

Overkill is probably good for some people's ego, but it doesn't mean better.

If the roof leaks and the decking gets wet, the roof failed no mater what the deck material is.
 
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DTE

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Jul 13, 2013
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996
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North Carolina
Nice pickup load !! :thumbup:

What did you have to pay for that plywood per sheet in North Carolina ??

I ended up at Home Depot and paid 18.06 each for the 19/32 plywood and I am putting T1-11 on the gables with Cedar battens to somewhat match my house. And 2 of those sheets had a little ding on the edge so I was going to leave them off and the salesman said if I take those he will sell them for half off so I said load them up.
 

Whitworth

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Dec 26, 2011
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OSB is garbage. You can spin it anyway you want, but it's not a quality alternative building product, rather just waste product masquerading as something else.

Pros: lightweight, cheap and covered in wax.

Negs: flimsy, doesn't hold nails well, disintegrates under wet conditions, small pieces have no strength, not as strong or rigid as ply.

Take 1/2" OSB on a roof, 24" OC, will sag under weight of shingles. See that **** construction everywhere. Just because it's common doesn't mean it's good.

That same 24" OC, would you jump up and down on a roof deck made with OSB or prefer to jump up and down on 1/2" plywood?

I know it's used everywhere, but I wouldn't use it on my house.
 

GYPSY400

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Mar 21, 2013
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Location
Naughton Ontario
Up here it seems like most houses with OSB roof you will be able to see the trusses after about a decade from the house being built. I guess the weight of the snow on 24" centers will make the OSB sag.


I see this in my area too, when my builder did my garage he said he uses 5/8 osb to prevent the sagging.

In regards to steel roofing, I have never seen anyone use sheeting under the steel.. The norm here is to strap the trusses with 1x4


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FullRaceMerc

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Jan 9, 2015
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SoCal (SGV)
I used the radiant barrier osb on the roof of the shop. It was 102* yesterday and I went up in the attic to check it out. With the ridge vent, gable end windows open and the barrier sheeting, it was hot, yes, but tolerable. Otherwise I detest OSB...

We prefer to use plywood instead of OSB, unless it is a radiant barrier job. It is hot enough around here that the barrier makes a big difference.
 

engineer031

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Jun 26, 2015
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131
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Ontario Canada
If you are using a metal sheeted roof and strapping it you dont need any plywood. Your metal will screw to the strapping.
If you are using an asphalt shingle I would only use plywood OSB has much less strength
 

stikman56

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Jun 12, 2014
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I'd never opt for OSB over plywood. Plywood has greater tensile strength, impact resistance, resists de-lamination better and so on. I've seen many pickup beds lined with an un-finished sheet of plywood which held up to hard use for years. Never saw that tried with OSB. Finally; they build boats out of plywood. Try that with OSB and you'll be sitting next to the Titanic.

-Valentine

Not true at all on strenght. OSB is stronger than plywood and also today is a good product. Plywood no longer is simply because it's so full of voids now. This information comes from my Dad who was a top dog lumber salesman for 42 years and knows more about wood than anyone I've ever known. If he says it, I listen. Only issue with OSB they've never been able to solve is edge swell if it gets wet. When I use the siding I simply wipe the bottom edge with Alex Plus clear and paint it. Never had that issue on my siding.
 
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reader2580

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Dec 31, 2014
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Minneapolis, MN
OSB is not waste product. There is enough OSB being made that trees are harvested specifically for OSB.

The old wafer board was really a bad product and gave anything made with wood chips a bad name.
 

finn

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The UP, God's country
OSB is garbage. You can spin it anyway you want, but it's not a quality alternative building product, rather just waste product masquerading as something else.

Pros: lightweight, cheap and covered in wax.

Negs: flimsy, doesn't hold nails well, disintegrates under wet conditions, small pieces have no strength, not as strong or rigid as ply.

Take 1/2" OSB on a roof, 24" OC, will sag under weight of shingles. See that **** construction everywhere. Just because it's common doesn't mean it's good.

That same 24" OC, would you jump up and down on a roof deck made with OSB or prefer to jump up and down on 1/2" plywood?


I know it's used everywhere, but I wouldn't use it on my house.

Old people have problems ajusting to change.

Code here is 5/8" for roof decking, so OSB is no problem.

OSB is rated for longer unprotected exposure than plywood is also.
 

speed bump

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Butte Montana
Not true at all on strenght. OSB is stronger than plywood and also today is a good product. Plywood no longer is simply because it's so full of voids now. This information comes from my Dad who was a top dog lumber salesman for 42 years and knows more about wood than anyone I've ever known. If he says it, I listen. Only issue with OSB they've never been able to solve is edge swell if it gets wet. When I use the siding I simply wipe the bottom edge with Alex Plus clear and paint it. Never had that issue on my siding.

The plywood comment depends on the grade you buy. Buy really good stuff it won't have voids or fill in repairs but it is expensive. Buy cheap stuff and it can have so many voids, so much cheap **** in it, and so many repairs to the plys.

As far as roof decking 5/8" OSB costs about 1/2 of what 1/2" plywood does at Menards. My sister is getting ready to buy a house my dad redid the roof on 28+ years ago and the 5/8" OSB they put up way back then is still in good shape without any bows or issues. Just because its different doesn't make it bad.
 

Whitworth

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Dec 26, 2011
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Old people have problems ajusting to change.

Code here is 5/8" for roof decking, so OSB is no problem.

OSB is rated for longer unprotected exposure than plywood is also.

I doubt you've even ever been on a roof deck.

OSB:

Splinters like crazy.

Blows out with pneumatic fasteners.

Swells like crazy.

Terrible underlayment.

Not as workable as ply (eg, hand plane or a spur bit)

A lot of apples to avocados in this discussion. Hi price OSB properties compared to low end plywood. I hate CDX almost as much as OSB. They're both garbage to a great extent.
 

yeldogt

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Jan 2, 2012
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Plywood comes in different grades. I never use OSB -- I have seen so many issues with OSB and moisture -- never use it.

I also don't like the off gassing.
 

valentine

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Oct 27, 2008
Messages
239
When they start using OSB to build boats, I'll start using it in my house. Since that isn't going to happen in my lifetime, I'll stick to plywood. I'm all for new technology and better materials but my experience with OSB hasn't been positive. Plywood has proven itself to me.

-Valentine
 
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finn

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The UP, God's country
I doubt you've even ever been on a roof deck.

OSB:

Splinters like crazy.

Blows out with pneumatic fasteners.

Swells like crazy.

Terrible underlayment.

Not as workable as ply (eg, hand plane or a spur bit)

A lot of apples to avocados in this discussion. Hi price OSB properties compared to low end plywood. I hate CDX almost as much as OSB. They're both garbage to a great extent.

I've personally done quite a few over the years, and paid for more.

Paying for them trumps building them with someone elses money.
 

Dbn107

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Joined
Mar 10, 2014
Messages
7
Advantech is best known for their osb subflooring, but they make roof and wall sheathing as well. Huber is the manufacturer (they make the zip panels as well). Aside from maybe marine grade plywood there isn't anything more water resistant. I've seen advantech hold up to ponding water on new construction where any construction grade plywood would have been a delaminated mess. So no, not all osb is garbage. I had a 1 1/8' full sheet sitting on saw horses outside for almost a year as a work table and it had almost no appreciable swelling.
 

DGS

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Mar 12, 2007
Messages
6
Location
Smithers B.C.
OSB used here in northern Canada, If it works here not sure why it wouldn't work elsewhere. If your roof sheathing is getting wet, it shouldn't be. Fix the problem. If you do have a roof leak you will have to rip up the shingles to repair, and in the worse case you will have to replace a couple sheets of 4x8.
 
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