Does Hardwood Flooring Need to Be Acclimated? What Homeowners Should Know

Yes, hardwood flooring often needs to be acclimated before installation, but proper acclimation is about more than simply letting wood sit in a house for a certain number of days. Hardwood flooring needs to reach an appropriate moisture content for the environment where it will be installed and remain after installation.

Proper hardwood flooring acclimation involves several factors, including the moisture content of the flooring, moisture content of the subfloor, board width, wood species, indoor temperature, relative humidity, and the conditions of the home during construction.

At Signature Custom Flooring, we don't determine when flooring is ready based only on how many days it has been inside. We measure the moisture content of the flooring and subfloor and look for the appropriate relationship between the two.

What Is Hardwood Flooring Acclimation?

Hardwood flooring acclimation is the process of allowing wood flooring to adjust to the temperature and humidity conditions of the environment where it will be installed.

Wood is a natural material that continually gains and loses moisture. As its moisture content changes, the wood can expand or shrink.

The purpose of acclimation is to get the flooring to an appropriate moisture condition before it is permanently installed.

The Goal of Acclimation Is Moisture Equilibrium

The most important thing to understand about hardwood acclimation is that time alone doesn't determine whether flooring is ready to install.

As a general installation guideline:

• Strip flooring: The moisture content should generally be within approximately 4 percentage points of the subfloor's moisture content.
• Wide-plank flooring: The moisture content should generally be within approximately 2 percentage points of the subfloor's moisture content.

The exact requirements can vary based on the flooring manufacturer, species, construction, installation method, and other conditions. The manufacturer's installation instructions should always take priority.

Why Wide-Plank Flooring Requires More Attention

Wood expands and contracts primarily across its width. Wider boards can therefore experience more noticeable dimensional changes when their moisture content changes.

Some Wood Species May Need More Time

When installing wide hickory flooring, we prefer to give the flooring additional time to adjust before installation. There isn't a specific number of days that automatically means hickory is acclimated. We want the flooring to have enough time to reach equilibrium and verify that through moisture measurements.

Acclimate the Flooring to the Home It Will Actually Live In

One of the most important parts of hardwood flooring acclimation is making sure the home is in an appropriate condition before bringing the flooring inside.

The goal is to acclimate the flooring to the environment it will experience after installation, not the temporary conditions of a construction site.

Complete Wet Construction Before Bringing Hardwood Flooring Inside

When possible, moisture-producing construction should be completed before hardwood flooring is brought into the home for acclimation. This typically includes painting, tile installation, grouting, drywall finishing, concrete or mortar work, and other wet construction processes.

The home should also be enclosed, and the heating or cooling system should be operating so the indoor environment is reasonably representative of normal living conditions.

How Should Hardwood Flooring Be Stacked During Acclimation?

Flooring should be stacked in a way that allows air to circulate around the boards. If boards are packed tightly together with little air movement, the material may not adjust as evenly or efficiently.

How Long Does Hardwood Flooring Need to Acclimate?

There is no universal number of days that applies to every hardwood floor. Factors include wood species, board width, flooring thickness, solid vs. engineered construction, initial moisture content, subfloor moisture content, indoor temperature, relative humidity, air circulation, and manufacturer requirements.

The important thing is not the number on the calendar. The important thing is whether the flooring has reached the appropriate moisture condition for installation.

Why Moisture Testing Matters

Moisture testing provides information that simply counting days cannot. A professional flooring installer can measure the moisture content of the hardwood and the subfloor and determine whether they are within the appropriate range.

The Subfloor Is Just as Important

If the hardwood flooring has the correct moisture content but the subfloor contains excessive moisture, the floor can still develop problems after installation. For concrete installations, appropriate concrete moisture testing is particularly important.

What Happens If Hardwood Flooring Is Installed Too Wet?

If hardwood flooring is installed with too much moisture for the conditions in the home, the flooring may lose moisture after installation. As the boards dry, they can shrink, resulting in gaps, open joints, cracks, separation, and changes in appearance.

What Happens If Hardwood Flooring Is Installed Too Dry?

If flooring is installed too dry and later absorbs moisture, the boards can expand. Excessive expansion can contribute to cupping, crowning, buckling, tight joints, and pressure against walls and other fixed objects.

Does Every Type of Hardwood Flooring Need to Acclimate?

No. Different flooring products can have different requirements. Solid and engineered hardwood, different species, board widths, thicknesses, manufacturers, and installation methods can all affect the requirements. Always follow the manufacturer's installation instructions.

What About Wisconsin Homes?

Wisconsin homes experience significant seasonal changes. Winter heating can make homes very dry, while summer can bring higher humidity. Wood responds naturally to these changes. Some seasonal movement is normal, and maintaining consistent indoor humidity can help reduce excessive movement.

What Should Homeowners Ask Their Flooring Contractor?

1. What is the moisture content of the flooring?
2. What is the moisture content of the subfloor?
3. What moisture-content difference are you looking for?
4. Does this particular flooring need to acclimate?
5. What does the manufacturer recommend?
6. How is the flooring being stacked during acclimation?
7. Is there enough air movement around the flooring?
8. Has the wet construction work been completed?
9. Is the HVAC system operating normally?
10. How will you determine when the flooring is ready to install?

Hardwood Floor Acclimation: The Bottom Line

Hardwood flooring often needs to be acclimated before installation, but acclimation is not simply about leaving the flooring inside for a predetermined number of days.

Proper acclimation means allowing the flooring to reach an appropriate moisture condition for the environment where it will be installed.

At Signature Custom Flooring, we consider flooring moisture content, subfloor moisture content, board width, wood species, indoor temperature, relative humidity, air circulation, manufacturer requirements, and the condition of the home.

As a general guideline, strip flooring should typically be within approximately 4% of the subfloor, while wide-plank flooring should generally be within approximately 2%, subject to the specific flooring manufacturer's requirements.

We also stack flooring to allow air movement and may allow wider material or species such as hickory additional time to reach equilibrium.

Most importantly, we want the flooring acclimated to the conditions it will actually live in. That means completing major wet construction such as painting and tile work before bringing the hardwood into the home whenever possible.

Proper preparation takes time, but it can help reduce moisture-related flooring problems after installation.

The goal isn't to install hardwood flooring as quickly as possible. The goal is to install it when the flooring and the home are ready.
If you're considering new hardwood flooring in Central Wisconsin, contact Signature Custom Flooring to discuss your project and the proper preparation for your flooring.