NWFA Installation Instructions

NWFA Installation Instructions

Your installation professional should follow the installation guidelines set forth by the NWFA. These are industry standards and are available by calling 1-800-422-4556.

Before Installation

Before installation any concerns about the milling or grading of this product must be directed to and resolved with the manufacturer. After the product is installed the customer assumes all responsibility. The manufacturer will not be liable for any costs of product or replacement if issues are not resolved prior to installation.

Job Site Conditions*

Kiln-dried flooring should be stored in an enclosed building that is well ventilated. Flooring should not be exposed to excessive periods of high humidity or moisture. All concrete masonry, sheetrock and framing members, paint, etc. should be thoroughly dry before flooring is delivered to the job site. The average moisture content of the sub flooring should be within 4% of the moisture content of the flooring before installation. From the time flooring is delivered and until occupancy, temperature and humidity should be maintained at occupancy levels.

Sub Floor*

Installation over a concrete slab or radiant heat will void our warranty. Plywood, 5/8” or 3/4″ performance rated products are preferred. Also, 3/4″ OSB is an acceptable substrate. Particleboard of any thickness is not recommended.

Laying and Fastening the Flooring*

Cover the sub floor with a vapor retardant such as 15lb asphalt felt or rosin paper, overlapping the ends 2-4”. Direction of the flooring should be at right angles to the joists. For strip flooring (3 ¼ width and narrower) use a 1-1/2” barbed flooring cleat or staple. Spacing between nails should be 8-10” apart. Nailing is required within 2” of the end joints and at least 2 nails are required per board. End joints should be staggered at least 6” apart. An expansion gap of ¾” should be left around the walls.


Maintain the relative humidity in the areas with hardwood flooring. Excessive swings in humidity will cause the flooring to crack, shrink or expand. The recommended range in relative humidity is 35%-50%. Use protector pads underneath chairs and heavy furniture. Place mats by exterior doors and high traffic areas use rugs that allow the floor to breathe (avoid rubber backed rugs). Vacuum or sweep floors to remove loose dirt then clean with Bona wood floor cleaner.

*Please refer to the NWFA Instruction Manual for more detailed instructions.

Sunshine Hardwood Flooring is a wood flooring contractor in Ada County that specializes in hardwood floor installation, dustless hardwood floor refinishing, custom wood floor makeovers and historically accurate repairs for older homes.