I'm replacing a kitchen floor. The original underlayment was masonite so I pulled it up. I'm going to put down a new layer of plywood underlayment on top of a 5/8 plywood subfloor. I will then put vinyl tile on top. My question is how to attach the plywood? Various sources have said staples, nails, screws, and glue. Nails seem to be the most popular answer, but part of the reason I'm replacing the floor is that the original underlayment was nailed and the nails were pulling loose and coming up through the tile. How do you recommend attaching the underlayment?
I think that you have the answer: "part of the reason I'm replacing the floor is that the original underlayment was nailed and the nails were pulling loose and coming up through the tile." Staples and nails will not hold for long, screws can do the job. You will want to figure out the location of the floor joists and install the screw so that they connect the new underlayment to the floor joists. In that way, you will "sandwich" the sub-floor between the joist work and the new underlayment.
I like to use "square drive" screws. These screws are installed with a square ended screw drivers or a screw gun bit. I find them very easy to use. Screw guns - electric screw drivers are great!
By the way, I just heard another story about vinyl flooring failure. The reason for the failure was the use of a glue which was not designed for the product in question. Always make sure that you are using the correct underlayment and glue for the selected flooring material. George