Installing hardwood floors, or how to use all your power tools at once...

First, you need to clean out all the old junk on your subfloor (carpeting, and old flooring), and check the floor for being level. In my case it wasn't, and unfortunately unless your house is very very old or very very new, it also has a warped floor. If the floor is not level, you have several options. If the floor is off by 1/8" to 3/8", you can put down a metal lath and pour concrete. In my case, the floor was about 1/2 inch higher in the center than it was on the sides, and at one spot on the center it was almost an inch higher. Flooring will bow and crack if installed on a floor like this, so something had to be done. If the basement was unfinished, you can saw up into the joist which usually relaxes the stress and levels it out (make certain you reinforce the area you cut into.) In my case, since I finished the basement and didn't want to do touch it ever again, I decided to pull up the subfloor and shave the main support joists back to level with the surrounding floor. This task is a bitch!

 
After you have leveled the joists, you need to replace the subfloor and then I recommend that you screw the entire floor down using either decking screws or drywall screws that are at least 2 1/2" long. This way you can almost ensure that you have none of those horrid squeaks. Getting rid of all those squeaks was a joyous moment for me!
Now the truly horrid task. The floor was almost perfectly level lengthwise, but settling has caused the sides to droop to far. I picked up a bunch of self leveling flooring concrete, and went to work. Note the metal lath in the far corner. This is necessary to strengthen the concrete!

On the right, notice that the concrete is hardened, and the floor is pretty damn level... I went over it a second time just to make sure, and with one or two low areas fixed, I was ready to go...

Here is the flooring installed over the subfloor... Notice the train track I installed in the dining room in the photo on the left. By the way all of these pictures are clickable if you want to see a larger result.

Here is the flooring installed over the subfloor... Notice the train track I installed in the dining room in the photo on the left. By the way all of these pictures are clickable if you want to see a larger result.
The small things make a difference, I replaced the old ugly floor registers with bright new ones... The only thing left to do was put in the moulding and clean up!