My dad swore by (and sometimes at) using resin-coated finish nails to quiet squeaks in floorboards.
My understanding of the "why" is that either nails pull loose from the joist below the floor, or the the floorboard softens, giving slack. Over time the board lifts a little, and moving up and down on the nail results in the noise. Resin, heated by the friction of driving, melts and adheres the nail to both the floorboard and joist.
I realize that if rot has occurred in the joist where the nail is secured, this eliminates all simple nail-replacement solutions; other solutions are possible, though, in this case.
Are resin-coated nails still the best solution for squeaks? Indeed, are they still available?
Thanks,