# Solid Maple Flooring over OSB



## Ron6519 (Mar 28, 2007)

Previous 5" ash floor was removed during a frozen pipe episode. That floor was glued and stapled down. The floor was in place when the house was purchased 3 years ago. It seems the subfloor is 3/4" OSB, glued and nailed down to 2x10 joists with a 12 foot span. The plan is to install 4 1/4" wide, maple, solid wood(3/4") T&G flooring.
This is the second water issue the house has been subjected to in it's brief(7 years old ) life. The OSB is in reasonably good shape with no swelling and little delamination. 
Any issue with OSB as a nailing surface?
Ron


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## Termite (Apr 13, 2008)

OSB is commonly used as floor sheathing, and you should have no issues with a hardwood floor....Properly installed....Over it.


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## AtlanticWBConst. (May 12, 2006)

Some of the best floor sheathing (IMHO) are modern manufactured forms of OSB. Don't confuse OSB Floor Sheathing (specifically engineered to be used as floor sheathing), with OSB Wall sheathing. Two completely different materials.

Example of the good stuff: http://www.huberwood.com/main.aspx?pagename=advantechflooring


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## Termite (Apr 13, 2008)

Be sure to put down red rosin paper or another good building paper under the flooring.


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## KUIPORNG (Jan 11, 2006)

*but these is my life experience*

Me and my neighbour got the same model of house built in the same year by the same builder around 2003. The difference is , I spent 2 thousands and somthing to upgrade my subfloor from OSB to PLYwood....

the builder give us both free first floor hardwood.

now the difference is... my neighbour's hardwood floor on the first floor have sound in various spots here or there... My don't have any....same story for the second carpet floor....

Was this bad workmanship as a coincident that both my first/second floor are somehow get good workmanship? Or it is difference in subflooring....

I would think these probably the cause:

our builder is cheap and use some cheap OSB boards and end up my 2000 somthing expense well worth it....


My neighbour happen needs to move away and his house is for sale for more than 3 months.... one comment his real estate agent tell him is asking him to replace all the hardwood flooring because people compain about the sound....


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## Termite (Apr 13, 2008)

KUIPORNG said:


> Me and my neighbour got the same model of house built in the same year by the same builder around 2003. The difference is , I spent 2 thousands and somthing to upgrade my subfloor from OSB to PLYwood....
> 
> the builder give us both free first floor hardwood.
> 
> ...


OSB and plywood are equally ideal for subflooring. If you've ever priced 3/4" subfloor...OSB or plywood...There's nothing cheap about either. Floor sqeaks and noises are more often attributed to poor installation of the subfloor or hardwood floor. Subfloor material has nothing to do with it.


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## KUIPORNG (Jan 11, 2006)

Here in Toronto OSB is about Half the cost of Plywood 4x8.... I did price it before....

I heard many people give the same comment as you.... but may be this thing is a regional thing... here in Toronto may be the OSB is of the bad quality type.... aslo , by the theory of physics.... OSB board is basically compressed broken small pieces of woods.... where as plywood is nature original piece of wood relatively speaking... which you would said will hold the nails stronger or last longer without loosening up.... or you can do an experiment... nail a piece of wood on OSB and Plywood with same nail(s) and pull them out... which one you think is easier to pull out... I bet OSB is easier, isn't it....


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## Amra (Aug 24, 2009)

> Here in Toronto OSB is about Half the cost of Plywood 4x8.... I did price it before....
> 
> I heard many people give the same comment as you.... but may be this thing is a regional thing... here in Toronto may be the OSB is of the bad quality type.... aslo , by the theory of physics.... OSB board is basically compressed broken small pieces of woods.... where as plywood is nature original piece of wood relatively speaking... which you would said will hold the nails stronger or last longer without loosening up.... or you can do an experiment... nail a piece of wood on OSB and Plywood with same nail(s) and pull them out... which one you think is easier to pull out... I bet OSB is easier, isn't it....


If properly installed, then a peice of OSB board would be equally difficult to pull a nail from as plywood.

There are a lot of factors that go into determining whether you will succeed or fail when using OSB (is it rated for floor sheathing, whats the span rating, what thickness etc etc), but most of the problems are simplified into two common issues.

Problem 1: Is the OSB you are using rated for for the amount of moisture present for your application, or only for use in an area completely protected from moisture. -- There are two main types of OSB, usually termed Exposure and Exterior. The exterior rated OSB uses wax, and waterproof glues/resins, allowing it to be used in areas of high moisture or weather, the Exposure rated (after installed) should be completely protected from moisture.

Problem 2: Did you SEAL the edges of the OSB after making any cuts that would expose the wood fibers? -- You should re-seal the edges after your cuts. It comes from the factory with waterproof paint on the edges, but if that is cut away then the edge CAN absorb moisture.

Assuming that you have sealed your edges and/or are using the proper OSB for your application, you should not be having an issue.

Plywood and OSB are constructed using nearly identical methods, they are both peices of wood stacked in different directions coated in wax and resin and hot pressed together to create sheets. The main difference is that plywood uses long strips of veneer instead of small chips of veneer like OSB.

Also, dont forget the importance of location location location. If your in an area where humidity, rain, snow or other forms of moisture are more prevalent, then naturally you will require using plywood or osb that has a higher rating against moisture, and using the "cheaper" osb/plywood in these situations will only result in problems, both immediately and down the road.

Lastly, Physics is not a theory, it is based entirely on real world phenomenon that are measured, and then constantly and consistently repeated and verified using the scientific process by thousand of independent sources. Theories on the other hand, while based on evidence cannot (yet) be verified for whatever reason. (i.e. we cant go back and watch the big bang, even though we see that all galaxies are moving away from each other).


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## Gary in WA (Mar 11, 2009)

I have to disagree. In the mid '80's, I started installing 3/4"OSB decking rather than 3/4"plywood. We all noticed a difference right away, the OSB was not as strong between joists, it was harder on the feet (more dense), and a lot noisier! When we dropped our material- headers, studs, plates, etc. on the deck- it banged like a gunshot. Unlike plywood, which is softer, stiffer, and quieter. You can tell the difference of which framers are using what by the loudness of the decking being dropped on the glued joists. (Instead of lowering the edge of the sheet down onto the joists, utilizing the time and effort of the glue installation). 

When I built my addition in '88, the lumber truck driver brought me OSB when I specifically ordered plywood decking. He said it's equal, I said it weighs more per sheet- among other points listed above. I had a bath scale nearby in garage, showed him ---- plywood = 35# OSB = 70# I believe it's all that glue because of all the tiny chips = weight, density, hardness, stiffness, and noise. 

If over a moisture area, use a vapor barrier or vapor retarder like tar paper or Aqua B- by Fortifiber found at box store. Or rosin paper, with no moisture stopping qualities, but good for squeaks. As mentioned by Kc, already.

Be safe, G


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## Amra (Aug 24, 2009)

I would also disagree if we are talking about OSB built back in the 80s. OSB back in the 1980s was a far cry from the stuff we use today.

You will find that the people who recommend plywood over OSB are generally an older generation of builders. In fact, its no different then when Plywood first started being used in houses, and all the older generations would recommend solid wood over plywood. Plywood stood the test of time, and now the same arguments pop up from plywood versus OSB. It happens with all newer technology, when engines became mostly computerized, older mechanics swore by the older carbureted engines, some still do.

Also, using words like softer, stiffer, quieter, lighter are all sell points that are based entirely on personal opinion (nothing wrong with that though), but if you do physical tests (i.e. actually build something with the materials) you will find that most of those words are issues that arise from completely unrelated problems. 

For example, if you use a span of 16 inches on center of your joists, then you can use thinner sheathing (7/16~5/8) but if you use 24 inches on center, then you need to use thicker sheathing (23/32~7/8). Using thinner wood on a wider span would make either wood "feel" like its weaker, but the issue is not the building material but rather improper construction.

Another example, if you do not use builders adhesive on the top of the joists, then eventually if/when the wood warps slightly and you walk on that area, if will flex, and will squeak. The same can happen if you do not use an underlayment before laying a floating floor or a laminate floor, without the underlayment it will eventually squeak. That of course is not the fault of the plywood or osb, but rather improper construction.

The point is that regardless of the building material used, assuming that you do the project to code and take all the proper precautions and necessary steps to prevent those future issues, then both OSB and Plywood are perfectly acceptable for nearly all types of construction. Thats not an opinion, thats a time tested fact, and eventually when particle boards such as MDF reach the quality of OSB and Plywood, we will be having this same discussion again.

Ultimately, if having plywood in there makes you "feel" better about the project, then by all means, buy it! It doesnt hurt anything except your pocketbook to use a more expensive material, so if you have the money to spend, go for it. The feeling of security is an important facet of owning a home, and while statistically it makes no difference, it might make a difference on a personal level, and that is the most important issue of all. No matter how good a performer OSB is, if you honestly are not confident in its ability, then it was always nag you in the back of your mind, and peace of mind is more important then the few hundred dollar difference in construction cost.


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## Gary in WA (Mar 11, 2009)

Ron, when I quit production framing (18-20 big houses a year) in 2003, we were using the "new" OSB. When nailing our spring braces to the floor, we always added a block to hold them down, unlike plywood. Of course, you probably won't be doing that application with your project. Lol. After we framed the first floor deck, I drilled 1/2" holes between the joists every 10' apart as it rains here, and this would drain the water off before it could puddle too deep. The OSB would settle a lot lower for deeper puddles, and the joists would show everywhere. At insulation, the vapor barrier would be spread in the crawl space, over the damp earth. Our feet were always sore from walking on the harder OSB and looked forward to framing on real plywood, every time it came up. It's one of the things you notice when working with something day in-day out for over 36 years of framing. We had a laborer that dropped a 2x4 stud from the roof to the first floor, it went right through the OSB. A year later it happened again, on plywood, it bounced off, no hole. (These are very precise, controlled experiments, lol) Here is some interesting reading for you about OSB* wall* sheathing, when wet. Granted, it is not the same as subfloor/underlayment. A little water won't hurt anyone...You always give info out for DIY'ers to read, now it's payback time: http://www.rci-online.org/interface/2003-06-haughton-murphy.pdf
http://www.eima.com/pdfs/The Perfect Storm Over Stucco.pdf
Be safe, G ps. You are not doing your own plumbing again, are you? Lol.


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