Acclimation and Moisture Control

Once you received your hardwood flooring your first step is to acclimate the new flooring to the normal lived-in conditions. It is allows best to follow the NWFA’s Acclimation and Conditioning of Wood Flooring (Chapter 2). Solid hardwood floors typically take anywhere from 5-14 days to acclimate. During this time, you will want to a Moisture Content Reader to keep track of both the Moisture Content of your sub-floor as well as the Moisture Content of the hardwood flooring. Moisture Content is the amount of free water being held within the wood. For hardwood flooring 4” or wider you are looking for no more than a 2% Moisture Content difference between your plywood sub-floor and the hardwood flooring being installed. For board widths less than 4” you can have a 3% difference between the hardwood floor and sub-floor. Actual acclimation time consists of the HVAC system being on for at least 48 hours, the windows or doors (except for coming in and out) of the home not being opened during the acclimation period, and the wood flooring spaced properly throughout the areas where hardwood is being laid.


Wood and Moisture Control

Wood is made up of small cells which are hydroscopic; porous and capable of absorbing moisture. When flooring is exposed to moisture from ground water, leaks or plumbing, humidity it will absorb this water and expand. Wood will absorb and will expand during warm, humid months in the summer and contract during cold and dryer times in the winter. Expansion and contraction of wood is perfectly normal during changes in weather. Wood is a natural material that seeks to be in balance with its surroundings and will take on, or give off, moisture with changes in relative humidity.

To achieve the best presentation, you will want to keep your home between 60°-80° Fahrenheit and within 35%-55% range of Relative Humidity, the moisture level within your home. It is recommended to purchase a Hygrometer, a device that measures the moisture in the air, to help maintain the proper Relative Humidity. They are inexpensive and can simply placed on a shelf or bookcase.

Some species of hardwoods as well as wider width plank floors are less stable which means they are more prone to fluctuations. The most popular of these species will include: Brazilian Cherry, Brazilian Walnut, Brazilian Teak, Santos Mahogany, and Tigerwood. You will want to pay extra attention to acclimation at the time of installation and relative humidity throughout the year.


Tips to Help Maintain potential Moisture Related Obstacles


Dehumidifier in the Summer Months

Summertime brings hot air which holds more humidity, this can cause wood planks to swell as they absorb the extra moisture. During the summer months you might want to run a dehumidifier to control moisture levels within your home. Again, check to maintain a relative humidity level between 35% and 55%.


Humidifier in the Winter Months

In the winter months, the cold air will draw moisture from your floor, causing it to shrink and contract. You can use a humidifier to add moisture into the environment. A humidifier adds several pints per hour to the house, therefore keeping the humidity at an acceptable level. Once again, check to maintain a relative humidity level between 35% and 55%.

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Anthony Civitello