NWFA Guidelines for Lumber

At Riverbank Rustic Lumber, we are proud to offer a wide selection of top-quality lumber products. We are committed to providing our customers with the best possible service and value. We recommend the following for optimum results for your projects.

Lumber should be stored properly at the jobsite - this means laying flat and out of direct sunlight in a controlled climate out of weather.

We recommend the NWFA Guidelines for Storage and Conditions and Acclimation found in Chapter 2 Part 1 Subsection A and B. The following section is the recommendation for hardwood oak flooring but can be applied to other hardwood and softwood materials as well.

CHAPTER 2 ACCLIMATION Part I – General Acclimation Guidelines

A. Storage and Conditions

1. Do not store wood flooring at the jobsite under uncontrolled climate conditions. Garages and exterior patios, for example, are not acceptable areas to store wood flooring.

2. Ideal interior climate conditions vary from region to region and jobsite to jobsite. It is your responsibility to know what your “ideal” climate conditions are and build your floor around those conditions. If the soil surrounding a structure is 3 inches or more above the floor of any level, consider that level below grade. This includes walk-out basements. In addition, the surrounding soil should be sloped away from a structure.

B. Acclimation

1. Ensure that the building is enclosed.

2. Verify that the building is maintained at normal living conditions for temperature and humidity. 3. Where building codes allow, permanent heating and/or air-conditioning systems should be operating at least five days preceding installation to promote proper acclimation.

4. If it is not possible for the permanent heating and/or air-conditioning system to be operating before, during and after installation, a temporary heating and/or dehumidification system that mimics normal temperature and humidity conditions can enable the installation to proceed until the permanent heating and/or air-conditioning system is operating.

5. Upon delivery, check wood flooring moisture content with a moisture meter to establish a baseline for required acclimation. Check the moisture content of multiple boards. A good representative sample is typically 40 boards for every 1,000 square feet of f looring. Acclimate to manufacturer’s recommendations or as necessary according to geographical location and your jobsite location.

6. Prior to installation, ensure that wood flooring is within acceptable range of moisture content with the wood subfloor. For solid strip flooring (less than 3” wide), there should be no more than 4 percent moisture content difference between properly acclimated wood flooring and subflooring materials. For wide-width solid flooring (3” or wider), there should be no more than 2 percent difference in moisture content between properly acclimated wood flooring and subflooring materials.

Additional Information

Tips for Acclimating Lumber

Tip #1: Allow Wood Flooring to Acclimate for At Least Three Days - Acclimation times vary by species and product, but a rule of thumb is to acclimate wood floor products for at least three days. You’re trying to reach an equilibrium between the moisture content of the wood materials and the air where the product is being installed. Acclimation is the process of reaching this equilibrium moisture content – that is, the point at which the wood is neither gaining nor losing moisture.

Tip #2: Break Flooring Materials into Smaller Lots Professional wood flooring installers recommend opening your flooring packages and breaking the shipment into smaller lots. This will increase exposure to airflow, which helps with acclimation. You may also wish to cross-stack planks using spacers between layers to increase circulation.

Tip #3: Site-Finished and Engineered Flooring Requires More Time to Acclimate - If you’re finishing wood floors on-site, you’ll need to plan more time for the flooring to acclimatize – as much as 5-7 days.

Site reference: https://www.oldewoodltd.com/what-to-know/resource-library/hardwood-floor-acclimation#:~:text=Acclimation%20times%20vary%20by%20species,the%20product%20is%20being%20installed.