How to Install Hardwood Floor in an Attic

How to Install Hardwood Floor in an Attic
From: diynetwork.com

Step 1: Lay Out the Underlayment

Vacuum the subfloor thoroughly, lay out underlayment and cut it to fit using a utility knife.
Use a chalk line to keep your boards square with respect to the walls.

Step 2: Cut and Install the End Boards

Using a miter saw, cut your end boards to size and install them along the wall at a distance of about 3/8" from the wall. You can cover the gap later with trim. Secure the boards using a nail gun.
Slide the next course of boards into place, staggering your seams and tapping with a rubber mallet.

Step 3: Secure the Boards to the Subfloor

As you work, use an angle nailer to secure the boards to the subfloor. Nail every six inches.
Tip: You can rent an angle nailer from a rental or home center, typically for about $50 a day.
Ease the last board into place with a cats paw and secure with a nail gun. You may have to cut the "tongue" off the board to make it fit.