The new hardwood that I plan on putting down is this: http://www.homedepot.com/p/t/202700081?catalogId053&langId=-1&storeId051&N=5yc1vZbejw&R 2700081 .
The subfloor that it is going on top of used to look like this:
That is old 3/4-inch thick tongue and groove subflooring that goes across floor joists that are 16 inches on center. But, since taking that photo, I added a layer of 30 lb roofing felt on top of that subfloor, and then put 1/4-inch SurePly Premium Underlayment on top of that. I added the roofing felt to help with absorbing sound, and I added the underlayment to make sure the floor was smooth and even, and to allow me to run the new hardwood across the floor joists and parallel to the 3/4-inch subflooring boards.
Rather than hiring a regular hardwood flooring installer to install the new hardwood, I decided to try doing this one "in-house" -- meaning I will use a contractor that I know and use for a lot of other stuff, and he and I will do the hardwood installation ourselves.
The plan is to rent a hardwood flooring nailer or stapler from a nearby tool rental place.
Does it make a difference whether we go with a hardwood flooring NAILER vs. a hardwood flooring STAPLER? I am leaning toward the nailer instead of the stapler, but I wonder if people here think that one is better than the other to use.
I have heard that it is a good idea to try to hit the floor joists if possible when nailing the new hardwood down. But, when I watch YouTube videos about this, I don't see anyone actually doing that.
With the 1/4-inch underlayment on top of the 3/4-inch subflooring, that adds up to 1 inch thick under the hardwood before getting down to the floor joists. The hardwood is 3/4-inch thick, so it is probably about 1/2-inch from the top of the tongue where the nails or staples will go in down to the bottom of the hardwood. So, the total depth down from the top of the tongue down to the top of the floor joists will be about 1-1/2 inches.
This is where the math part comes in. I think the nails or staples end up going in at a 45 degree angle -- is that correct? If not, that would make a big difference in calculating the length of the nails or staples and whether they will reach the floor joists.
But, if 45 degrees is correct, and if I use 2-inch nails or 2-inch staples, am I correct that the nails or staples wouldn't even reach the floor joists anyway? I'm doing the right angle triangle formula where A-squared plus B-squared equals C-squared, meaning the hypotenuse would be the square root of 4.5 inches which is the sum of 1.5 inches squared (A-squared) plus 1.5 inches squared (B-squared). And the square root of 4.5 is about 2.1 inches -- which would be the length of the nail BEFORE it would reach the joists).
My questions really are: how long should the nails or staples be?; should I bother trying to hit the floor joists underneath?; and, I assume I nail every board but how far apart should the nails/staples be placed along each board when nailing?
And, of course, any other thoughts or suggestions on this would be appreciated.