Lay out several rows of loose boards along the length of the floor, following your plan. Mix boards from several bundles to avoid noticeable color changes from one bundle to another. Arrange lengths, wood-grain patterns and variations in board colors to create a balanced look. To avoid confusion when installing random-width strips or planks, lay out the boards in alternating courses based on width.
Choose long boards for the first row and align them along your chalk line with the board tongues facing out toward the center of the room (image 1). Place the first board in the row so that its groove end aligns with the chalk line at the end wall. Be sure there is a 1/2-inch gap between this row and both the side and end walls.
The first row needs to be face nailed. To prevent the wood from splitting, drill pilot holes along the gap edge every 10 to 12 inches then top-nail the starter course with 10d finishing nails (image 2). Try to make sure they go through the sub-floor and into the floor joists. Use a nail set to sink the nail heads slightly below the wood surface (image 3). Secure this row by blind-nailing or stapling through the tongue joint with the power nailer.
After the first row is firmly attached, begin at one end and use the power nailer to install the next row of boards (image 4). If the boards don’t fit together easily, use a mallet with a scrap piece of flooring as a tapping block to knock them into place (image 5). Be careful not to damage the edges or board surfaces. Install one complete row at a time from end-wall to end-wall. Place at least two nails in every board — the rule of thumb is to nail every 10 to 12 inches.
Flooring is typically bundled in random lengths. Vary board lengths as you install so you will have staggered end-joints in a random pattern (image 6). Avoid repeating patterns — a repetitive joint pattern can result in a weaker floor. Installers recommend staggering end-joints a minimum of 6 inches for narrow-strip flooring, 8 to 10 inches for planks that are up to 5 inches wide, and 10 inches or more for wider planks. When a row approaches an end wall, select final pieces that will be a minimum of 12 inches long. Don’t forget to leave a 1/2-inch gap at the wall. Measure and cut off the ends, then use these cutoffs — with their tongues or grooves intact—as starter pieces for the next row.
Do not attempt to cut boards to length within the floor pattern. Flooring strips have chamfered edges to help them lay flat where they meet. Cut boards to fit only at the end of a row where refinishing the board ends is not necessary.
Make sure each board is locked tightly against the preceding row, because even a small gap can cause the entire floor to be off. Any variation must be corrected when and where it appears. Gaps between boards can be caused by misalignment, poorly milled edges, wood splinters in the grooves and other obstructions. If you have a gap, pry out and discard the board, eliminate the damage or obstruction and reinstall a new board.
When installing up to a threshold, it is not critical to cut each row’s end to an exact length. After the floor is complete, you can use a circular saw to cut across the ends for a precise fit.
As you near a wall or other obstacle, clearance for the flooring nailer may be restricted. Where necessary, drill pilot holes and hand-nail the boards, blind-nailing through the tongue joint if possible, or face-nail and set the nail heads below the board surface.
Where the final row meets the wall, it may be necessary to rip boards lengthwise to fit. Narrow end boards are usually hidden by base molding.