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Piffin

02:12PM | 07/29/05
Member Since: 11/06/02
1284 lifetime posts
it sounds like since you are already closed in, you can control moisture, so OSB would suffice, as long as you use a thickness approved in your area for subfloors. I would use a minuiomum 3/4"

Excellence is its own reward!


homebild

09:02AM | 07/31/05
Member Since: 01/28/03
694 lifetime posts
Piffin:

Thanks for the input on the topic but allow me to clarify some of your misconceptions.

You said:

"There is a fine error here. OSB has not been on the market for thirty years....OSB has only been with us for a little over twenty years - perhaps as much as 25, but no more. before that, its predecessor was waferboard which is the source of much bad publicity, well deserved."

--Right, but I never said I have used OSB for all of those 30 years and the articles I have posted from the researchers indicate the rpoblems with the earliest forms of OSB and 'aspenites' and 'waferboards' whioch should not be confused with modern OSB.

Piffin also said:

"But I will never allow it on any roof that I build. It is not acceptable for that use. Seams will telegraph and dips will show through an asphalt roof. it has not the same lateral strength needed to support snow loads. Perhaps you live in an area where snow is light."

-Well that is your opinion, but it is not mine. OSB does NOT 'telegraph' through shingles unless it is improperly installed.

And it is just plain FALSE that OSB does not have greater lateral strenght. In fact the opposite is true. OSB has GREATER sheer and load bearing strength which is why you can user thinner sheets of OSB than plywood for equal spans. The scientific and code research backs this up universally: OSB is stronger than plywood, but for all intents are treated as equals for simplicity sake for load bearing and sheer strength. And YES I live in a region of high snow load and have never seen any failures due to the use of OSB alone.

Piffin then said:

"You don't suppose there would be a market for this newest generation of chipboard product if the old OSB was really any good do you? OSB is going the same way that waferboard did - because of its reputation as a second rate product."

-OSB by any other name is till OSB. OSB simply means an engineered sheet wood product made using the technique of using "oriented stands" of wood fibers that are pressed and glues into place...The process name has nothing to do with product or trademark identity....But it is true that OSB, like all engineered wood products even plywood, is an EVOLVING product and process and was also addressed in my links.

The reality is that no matter what you call it or how you package it, as long as the basic process stays the same it is still OSB.

So I disagree completely that OSB is going anywhere. OSB was 'waferboard" and OSB is now 'Advantech' and OSB will be other things in the future as this product remains.

Piffin finally said:

" The OSB has been with us for a generation and deserves the rap it gets. The builders who favor it base their choice not on studies of factual experience, but on price. Experrience shows different. If you can cover it up fast enough to keep it from ever getting damp, it is probably OK in light load conditions. But it will deteriorate when wetted. It will sag in roof situations. You fight a losing battle to defend it against those of us who know better from long experience. "

Again, this is completely FALSE and the research concludes oppositely from what you have stated and I can only base you acceptance of these myths based on not having read any research on the issue...and if you can produce any research to refute what I have stated I'll be glad to consider it. But the reality is:

-OSB is superior to plywood for load conditions as the research openly states

-OSB does not sag when wet anymore than does plywood.

-OSB is BETTER at repelling water than plywood because it takes longer to saturate than plywood. The only issue with OSB is that when it swells from having been wetted, it does not return to its original shape as easily or as readily as plywood.

-OSB does NOT rot as easily as plywood. Their characteristics in this area are the same.

And again, MY experience and the scientific research does not agree with your claims....


homebild

09:12AM | 07/31/05
Member Since: 01/28/03
694 lifetime posts
Piffin brought up price as being one of the few reasons to use OSB.

Well, it is certainly ONE reason, and is essentially the same reason that homes are no longer sheathed with true 1x12s.

The price of 1x12s is so much greater than plywood per square foot that plywood replaced solid wood sheathing DESPITE THE FACT THAT PLYWOOD IS INFERIOR IN MANY WAYS TO SOLID WOOD SHEATHING.

The same might be said about the reasons why OSB is rapidly replacing plywood sheathing considering that OSB cost can be 2-5X LESS than plywood depending upon location.

Right now OSB cost about 1/2 that of comparable plywood in my region and was as great as 5 x cheaper just before Bush Iraq war artifically drove up the cost.

So having a cheaper cost product does not necessarily indicate a bad thing, and price is ultimately the driving force in constuction which is why we don't hand dig or build stone foundations anymore or why we don't frame homes with true 2x stock lumber anymore...

But cost is NOT the only factor in using OSB over plywood, performance is.

homebild

09:14AM | 07/31/05
Member Since: 01/28/03
694 lifetime posts
"I am having hardwood floors installed. I am combining two rooms and the one room is a step lower. I added the floor joists to bring the floor up and now want to square off all the floor with wood then put the hardwood floors on top. Can I use OSB down or wood plywood be better? Cost is an issue and that is why I was thinking of OSB."

There should be no issues using OSB since it has been shown that OSB flooring has the same or better nail holding charcteristics as plywood and OSB costs less.


ama572

03:25PM | 11/10/07
Member Since: 11/09/07
1 lifetime posts
Homebild-Do you work for an OSB manufacturer?

You guys may be comparing apples and oranges a bit here. keep in mind that there are 2 grades of plywood (interior /exterior). OSB has different types of grades depending on usage.

I think most would agree that if the usage is for an area that may sustain more than one month of periodic rain/wetness before being able to be 'roofed' over or vapor barriered, that plywood is much better in general.

For example, OSB floor edges will turn up if it stays wet for longer than a month, whereas plywood would take a lot longer. Obviously depends on how often it rains and how wet it stays. Some builders are notorious slow and behind the gun and cut corners.

Homebild, BTW, most OSB that builders use has LESS sheer and lateral strength than plywood. Keep in mind that tobacco companies told folks smoking was safe and didn't cause cancer either.

And while you 'builders' sit and crow about years of experience, mull over this information is coming from a retiring PhD Structural Engineer with 40 years "experience" with copious laboratory/field testing experience.

OSB is almost always used because it's cheaper, not because it gives superior structural support over plywood. Give it a rest folks.

Hydrexsanjose

10:48PM | 06/07/09
Member Since: 06/07/09
1 lifetime posts
I am a termite inspector and find that in most cases OSB products become damaged quiclky when exposed to excessive moisture. If you can be sure that you will never have a roof leak, shower leak, plumbing leak or any type of adverse moiture conditon you will be fine but we all know that this is far from reality. Leaks will cause damage and require replacement of OSB if not caught fairly quickly. Plywood and sheathing boards clearly hold up to adverse conditions much more that OSB. I can only hope that this will be corrected in the future and that our scientists and manfacturers would gain a great deal of true data if they would perform detailed inspections of many differet structures built in many different condtions and enviroments 10 -20 years after construction. I know that superior products equal not only strength but also longevity. So what is better and how many trees and how much construction cost do we actually save if we have to replace the wood materials more often? It is less expensive for the 1st builder but for the consumer it may be much more down the line

I know that when I inspect a structure that OSB materials are present my pen tends to get used much more and the repair cost is much higher than stuctures built with conventional building materials.

I do appreciate that this is an attempt to use more product than waste and the overall cost effectiveness to the actual builder is much lower.

I have seen a few nightmares that would have not been so horrible if other products were used other that OSB

1QualityRoofing

05:25AM | 11/27/09
Member Since: 11/26/09
3 lifetime posts
Embrace New Technology & Ecology Methodologies.

If we are speaking about Standard “CDX” Plywood and not “Treated”.

Today “OSB” meets or exceeds every important spec above “CDX” plywood. Period!

After installing over 10,000 new roofs and specializing in re-decks, I would never again install standard 1/2" CDX plywood, over standard 7/16" OSB. As far as price goes, yes on a normal size home OSB is about $100.00 cheaper. However I would up sell it even if it was more. It’s better and saves millions of trees.

Test It: Try leaving out in the rain 1pc. of OSB outside next to 1pc. of standard CDX. Wait a couple days and then reply to say "I was wrong"

Old School vs. New School

Quality Roofing

007bond7

01:24PM | 01/25/10
Member Since: 01/24/10
1 lifetime posts
ever laid a hardwood floor.Would you choose OSB or ply?

I would never lay a hardwood floor on OSB.It is cheaper sure.OSB is used because its cheaper not superior.I have a home bulit in 1850 post and beam.The siding is wood.Aluminum and Vinyl are superior right?

BV001141

09:21AM | 05/26/13
We have OSB subfloor in bedrooms and upper hall; wish to replace carpet with hardwood flooring. Should the OSB be replaced with plywood? One issue is lining things up with existing hardwood staircase. Should contractor replace OSB with thinner subfloor to use 3/4 nail down oak (which I intuitively wonder "what" it is being nailed into due to the thinness of the subfloor) or is it better longterm to go with a thinner oak flooring choice installed over the existing OSB? Told existing subfloor is in good shape and just needs a few more nails for a couple of joint squeaks (pulled back hall carpet to check out subfloor). Getting mixed opinions from contractors.

Also, we have existing hardwood flooring downstairs that needs refinishing (25 yrs and faded, but in good shape). Is it a big upcharge to "lighten" the existing medium brown stain (vs re-staining medium shade)?
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