No this is standard installation procedure. Theres no way to nail every strip into every joist. The osb will do just fine. Make sure that the osb is tightly screwed to the joists.

Thanks. Can you clarify the statement "There is no way to nail every strip into every joist." Can't you hit every joist If you are laying the oak strip perpindicular to the joists if you mark the locatin in advance or use a lazer line?

I also concur that it is not standard installation procedure. You might think that attaching your finish flooring through the subfloor and into the joists makes for a better job, but it actually can lead to problems with an installation.

For example, I once did a maple floor that was problematic. The house in which it was installed had joists directions that changed from room to room. The flooring ran continuous throughout these rooms. I thought it a good idea to fasten into the joists wherever I could do that. Well...when the wood shrank, due to a improperly designed HVAC system for the house, the boards fastened into the joists could not move with the rest of the flooring and very unattractive twists and splits occurred wherever the flooring was attached through to the joists.

Same thing with many other flooring materials, such as vinyl sheet or tile over panel underlayments. Underlayment manufacturers specify that underlayments not be fastened into the joists, apparently for similar reasons. The finish flooring needs to move if environmental conditions insist that it be required to do so.

The only situation where I have seen solid T&G strip wood flooring nailed into the joists is in single construction floor systems where there is no subfloor and the T&G flooring is nailed directly to the joists.

Yes i will explain further. When i said you cannot nail every board to the joist. Not all the strips are the same size. Some will be less that the joist span. Another reason as the other poster pointed out is that you want the floorvto be able to expand and contract independantly of the joists. Some of the nails will hit the joists but not deep enough to secure it. Depending on the type of nail and or staple the contractor uses it will hold just fine.

Thanks much! I really appreciate the full explanations of "why" as well as "how." Your information raises two other questions.

1. Will the nails or staples hold in 3/8 inch plywood, which part of the room has?

2. In a 60-year old house(a different house) that has slats instead of OSB or plywood subfloor, I would like to eliminate squeeks. I was planning to locate joists and use long screws. I believe the kits they sell to eliminate squeeks use long nails or screws. I suppose this would not work?? What would work?

Let me address your questions independently. First the 3/8 plywood will hold just fine. It raises the question is there going to be a height difference ? Meaning is the hardwood being layed going to run continusously into the 3/8 or is that in a different part of the house. The fasteners will hold but it raises concern about stability of the floor. Usually hardwood is layed over 3/4.

Second question. In a older home that has slates are you talking about securing the slates to the joists? Are you trying to eliminate the squeeks from the hardwood floor? If the slates are exposed meaning theres no floor layed over it you can just nail or screw(screws hold better) to the joists. Now if the floor is already layed over the slates you can nail or screww the floor to the joists but you will see the nails. And will look like crap. Typically the squeeks are not just in one place and before you know it you have 300 nails through out the floor. If you dont care about that then no problem. Or you can just lay carpet. But to secure hardwood to it with that method of nailing and wanting to keep the hardwood. You are better off replacing.

Thanks Gregg.
First question: The room is a 13 x 19 ft. kitchen, where about half the room is a bump-out added by previous owners about 18 years ago. The bump-out (about 9 x13 ft.) has the joists in front to back, whereas the rest of the house is left-right. To complicate matters, the floor of the bump-out is slightly higher than original house (yes there was a small bump in the middle of the room). So to get all the floors even and even with the dining room, the contractor is using 3/8 inch subfloor on older part of the kitchen and 3/4 subfloor where the bump-out is. The oak florring (tradditional 3/4 inch strips) will go the long way in the room and the entire room is supposed to look the same. Will this floor be stable?

Second Question: The floor in the older house is already layed over the slats and I thought I would just select some especially bad squeeks and not do the entire floor, so it won't look too bad. I would counter-sink nails or screws and use wood filler, topped with polyurethane. I realize I will see the filled in spots, but would use some judgement as to not do too much of the floor.
Do I follow the rule you mentioned earlier to avoid nailing or screwing into joists, or to not use screws that are too long into the joists?

Your first question. The floor will be ok. No worries about the height difference. Your flooring guy is doing it correctly.

Second. With the old house this is what you can do. Do you have access to a finish nailer?? That would be ideal since you can quickly nail the floor while leaving minimal evidence. If not find some 2.25-2.50 inch finish nails. And the pre drill then hammer in desired spots. The reason behind using finish nails is that finish nails have a small head and wont be as noticable in the floor. You can use screws but you would need a drill bit with a counter sink to make sure you can bury the head of the screw but hence you will have a noticable spot to fill with putty.

Good luck!