Step #1: Prepare the Sub-floor.

Prepare you sub-floor by making sure it is level as possible, all damaged spots are repaired, and that it is sound and has the strength to hold you new wood floor. Make sure it is smooth, clean and moisture-free. Remove all baseboards and trim in places where it will interfere with your installation. If you don't want to remove trim around your doorways, saw a gap big enough at the bottom for the flooring to slip under without leaving too much of a gap, especially if you will not be using shoe molding. Further prepare your sub-floor by laying 15-pound asphalt felt (roofing felt) or some other type of vapor barrier such as resin paper and tacking it to your sub-floor with staples. Seams in the felt or paper should overlap about three inches. A vapor barrier will help your floor be more resilient, resist moisture, and create sound absorption. Once the vapor barrier is in place, mark the center of your room with a carefully measured chalk line parallel to the wall you will start installation on.

Step #2: Start Installation.

You will want to install your hardwood floor running perpendicular to your floor joists for structural reasons if you can. For large rooms, it is best to start the installation of your tongue and groove hardwood floor in the center of the room. It isn't necessary to start installation in the middle of the room for smaller rooms, but begin at one wall. Your wood floor will expand and contract as the humidity of your home changes. As you install your flooring, leave a ½ inch perimeter around your room to allow for expansion and contraction. Start with your longest, straightest boards and nail them parallel to your chalk baseline.

Step #3: Installation.

Continue from your starting point attaching each new piece with the tongue of the prior piece. Use a flooring nailer or hammer and nail-set to nail down each board. Depending on the tongue and groove make-up of your flooring, you may snap boards into the groove of the previous board, or you may use a rubber mallet to tap them into place. When using the mallet method, leave enough room between boards for expansion. Use a jigsaw to cut irregular shapes at the edges of the room. When installing the edge pieces around your room, you probably won't be able to tap them into place, so use a pry bar or counter-lever to make sure they fit snuggly into place. Don't worry too much about damaging the edges as most of the board will be partially covered by baseboard and shoe molding.

Step #4: Finishing.

With a pre-finished floor, you won't have much finish work to deal with. Re-install your baseboards and trim work to cover the ½ inch gap at the edges of your room and if needed install a shoe molding as well. If any nails are below the level of your flooring, use wood filler that matches your flooring or a drop of urethane finish.