Comments by some very NWFA certified installers regarding OSB and links to information regarding osb and links to more information regarding this issue.

Virginia Tech has documents that show the holding power of fasteners is greatly reduced if the mc of the subfloor is high at the time of installation. Reinstalling a floor on OSB that has been dried to the normal seasonal mc range can work however i am not sure it is worth the risk. If you must install on OSB pay very close attention to your nailing schedule and the subfloor span and spacing of the joists because vertical deflection can and will be the straw that breaks the camels back.

it has always been my understanding that the main issue with staple in OSB is that the 2 points of the staples exert a lot more blunt force over the width of the staple. This tends to punch out potentially larger pieces of the OSB on the back of the subfloor. This may not be the case anymore but I know this used to be the case with OSB.....when this happens ( knocking out chunks from the back of the subfloor using staples) there is less holding power on that particular staple......of course this doesn't matter if the OSB is simply a top layer over existing plywood. With a cleat there is less chance of this "knockout" happening since there is only one point pushing through.......


http://osbguide.tecotested.com/pdfs/en/el812.pdf
http://www.rci-online.org/interface/200 ... murphy.pdf
http://www.mastercodeprofessional.com/m ... lywood.pdf

Thought I posted this before. A nice long thread hardwood installers opinions on OSB.

http://hardwoodfloorsmag.com/forum/topi ... g-osb.aspx

In the UK the main flooring left by the builder is chipboard. Not as good as plywood but still grips the nail. OSB is only for the garden shed roof.

I doubt what the spec would be for adding multiple layers or just a single one but it is pretty obvious that someone screwed up here with using the parallel one for the joist. You should consult first with the real specs.

Then check it with your builder so that you could check whether the claim would be right and so he would not have a good argument should he falter with what he chooses to present. You are at the losing end here so they are going to make it hard for you.

UPDATE:

Over six months ago, I brought in a lawyer in order to get the builder to act. We came to an agreement. The builder would pay to have a home humidifier installed in the central heating and cooling system, so that the house could be kept at a 45% humidity all year round. Once installed, the agreement was that if after 6 months, the floor was still creaking, cracking, and popping, then the builder would replace the floor.

Well, it has been 6 months now, and my house has remained at a minimum of a 45% humidity the entire time. The floor is no better than before. The question I have for the experts here is, what is the best way to replace an improperly installed hardwood floor? Should the hardwood floor planks be replaced with new wood? What about the OSB subfloor? Should the OSB subfloor be replaced, or should a new layer of OSB be added on top of the existing subfloor?

First, I want to add to the original poster. If your using a fastener that is longer than the thickness of the wood and OSB that is going to blow through the bottom of the OSB, then why not use a shorter fastener?

@ Luke, just my opinion but I think is documented in research. When OSB has been damaged by water it is not going to fix itself when dried back down or by adding moisture via humidification. When it is damaged and will not sufficiently hold a fastener it is history. So, why would you want to fasten more OSB to damaged OSB? What would be the point?

So it is best for the sub-floor to be replaced?

This is a true statement. They paid for it and they own it, to do as they wish with the report.

At this point it is up to you to get your own independent investigation done.

I would replace the sub floor,since I will be doing the same thing to my whole house(and making sure it's level too.).