Nail-down installing pre-finished solid wood floor

1. Choosing wood floor

Always choose reputable brand names through authorized dealers or stores, because they have much better quality control, storage and transportation system than smaller ones. Their products usually meet industry standards in terms of specifications, moisture content, grading, warranty, finish and other regulations. Accordingly the prices are slightly higher than cheaper counterparts.

2. Delivery and acclimation

Never deliver wood floors during raining day. Never store your wood floor in garage, because it is cold and not humility controlled. If floor is packed in plastic sheet, the package must be opened for acclimation. Acclimation is critical for successful wood floor installation. The purpose of acclimation is: 1. bringing moisture content of wood floor or sub-floor to equilibrium level; 2. bringing the temperature to a room condition. Therefore, understanding your local equilibrium level becomes very important. A good moisture meter is a must-have device for any hardwood floor installation job. The meter will tell if your wood floor or sub-floor is safe for your local equilibrium level. In other words, if your moisture content is good, the acclimation is redundant.

3. Jobsite environment

Permanent air conditioning and heating systems should be in place and operational. The installation site should have a consistent room temperature of 60-75 degree F and humidity of 35-55% for 14 days prior, during and until occupied.

4. Sub-floor qualification

Preferred sub-flooring: ¾” CDX plywood sub-floor; or ¾” OSB sub-floor with joist spacing 19.2” on center or less. Make sure the sub-floor is level well. The sub-floor should be flat to within ¼” in 10’ or 3/16” in 6’.  If not, have general contractor or builder correct it. Sometimes, a structure engineer is needed. 5/8” and ¾” thickness construction plywood are good for wood floor installation. The direction of the wood floor should be perpendicular with the joists, otherwise another layer of plywood minimum of 3/8”thickness need to add on top of existing one. Nail-down installation must be applied on ground level over basement, or above ground level. The difference between the moisture content of the sub-floor and the wood floor must not exceed 4% for strip, 3% for plank.

5. Tools and materials

Pneumatic hardwood floor nail gun; Pneumatic finishing nail gun; Tape measure; String; Weighted rubber mallet ; Circle or miter saw; Electric under-cut saw; Electric drill; Flooring screws; Chalk; 15-lb. felt floor liner/paper or rosin paper; 2" flooring nails; Finishing nails; Pull bar; Tapping block; Screw driver; Wood filler; Broom and dust pan; Eye protection;

6. Installation

Place 15lb. felt paper, or building paper over wood sub-floor. Snap a line parallel to the starting wall allowing ¾” expansion gap between and the edge of the first plank, and around the perimeter. Racking rule of thumb: stagger end joint a minimum of 6” between pieces on adjacent rows. Top nail first or second row, and blind nail the rest of rows with floor nailing gun until top nailing required again. Blind nail through the tongue using 2” barbed flooring cleat, 7d or 8d flooring nail, or 2” staples with ½” crown. Use 1-1/2” length nails with ¾” plywood sub-floor direct to concrete slab. Nails or staples should be spaced approximately every 8”