Acclimation

Gaps and cracks… These are the number one wood flooring complaint phone call that happens annually across the United States from December to April every year. We close the doors and windows and turn on the heat and never look back.

Have you ever had chapped lips? Your skin splits and cracks from moisture loss. The same thing is happening to a wood floor in the winter that is developing gaps. Just as your skin is alive, your floor is alive to an extent and let me explain…

When a tree is still alive conducting water, its wood fibers are saturated (about 25% moisture content). To make flooring, the tree is cut down and often allowed to air dry. The log is then rough sawn and stacked where it heads into a kiln. The process of kiln drying reduces the moisture content of the boards to approximately 6-9%. Kiln drying a wood floor close to 0% moisture content would be detrimental to the wood fibers. Wood flooring needs a certain amount of bound water in the cells to maintain its cellular integrity (6-9% is ideal). Decreasing the bound water below this will lead to cellular wall collapse and tearing.

How the problem begins

When a hardwood floor leaves a good manufacturer it will be bundled or boxed with a moisture content that is close to the 6-9% range. Afterwards, the wood flooring travels through several stops, where it can gain or lose moisture depending on the ambient conditions. Upon arrival to your home, most manufacturers require an acclimation period prior to installation…This is where facts and figures often turn into myths and misinformation.

Before ANY wood floor is installed anywhere, it is essential to determine the moisture content at that time. This requires the use of a properly calibrated moisture meter, which any experienced installer should have. Although my experience suggests 80% of wood floor contractors either do not own or choose to use a moisture meter. Checking wood flooring moisture at the time of an installation is akin to weighing yourself prior to beginning a diet. It provides the starting point for the goal of having a ready to install wood floor…

For example:

Let’s say that your wood flooring arrives at 8% moisture content, whereas normally it arrives at 6% MC. Your contractor shows up on the day of the job, but his moisture meter is at home with a dead battery. He decides that because he knows the mill, the weather around Central Oregon, and is an “expert” that the floor is fine to install. A week later everything looks great and everyone is paid. That is basically when your floor starts to experience life in your home and all its cracked up to be (punny huh?)

Installing an 8% moisture content floor in Bend, Oregon without expecting gaps is like walking through Tijuana with a huge bag of cash expecting not to be robbed. Wood flooring that has acclimated to this region prefers to be approximately 6% moisture content. So if you install a wood floor that loses 2% moisture content, then you should expect significant issues with gaps or dry cupping from shrinkage.

The RIGHT? answer  

The relative humidity of your home can fluctuate considerably, especially in Bend. Without supplemental moisture, the interior RH of most homes is approximately 15-20% on the best days. Virtually every wood flooring manufacturer REQUIRES a constant 30%-50% relative humidity level in your home to meet installation and maintenance guidelines. 

In the simplest of terms: If you live in Bend, Oregon or anywhere east of the cascade mountains you will need to add a humidification system to your heater unless you like gaps and cracks. If the retailer of your wood flooring does NOT mention this, then they could be liable for the resulting issues with your floor.

The Essentials

• If anyone is installing a wood floor in your home, they MUST measure the moisture with a meter to provide accurate information. Failing to do this WILL void any warranty by the manufacturer if a problem develops and later needs to be investigated.
• The relative humidity level in the air in your home is dynamic and not static
• Acclimation is ONLY a preparation period for your wood flooring. After a wood floor is acclimated, then proper relative humidity levels MUST be maintained to retain your warranty.