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What Size Screws Should I Use?

Question: I am building a small addition on the back of my house. I am at the point where I will be screwing the OSB sub-floor to the floor joists. My next-door neighbor said that the screws that I chose (2") are to long and that they would pop up of the sub-floor!

It would seem to me that the longer the screws the better the holding power and if the holding power is better they would be less likely to pop up. Is he right?

Answer: I can understand your dilemma, it would seem to make sense that the longer the screw, the less likely it would be to pop up. But, your neighbor is 100% correct, the longer the screw the more likely it is to pop up and release its grip.

In the vast majority of cases, flooring fasteners pop up because the joist lumber will shrink. Staples pop up more than common nails and common nails more than long screws and long screws more than short screws.

If you follow the link, you will find a detailed explanation of lumber shrinkage and screw length. Because of the inherent holding power of screws, they do not need to penetrate the joist more than 3/4".