Hardwood Flooring Acclimation: Why It Matters

Acclimation is one of the most commonly skipped steps in hardwood flooring installation — and one of the most important. Skip it or rush it and you risk a floor that cups, gaps, or buckles within months of installation. Here's why acclimation matters and exactly how to do it right.

What Is Wood Acclimation?

Wood is a hygroscopic material — it absorbs and releases moisture from the surrounding air. As moisture content changes, wood expands (gains moisture) and contracts (loses moisture). This movement is a natural property of all wood products.

When hardwood flooring is manufactured, it's dried to a specific moisture content. During shipping and storage, the flooring is exposed to varying temperature and humidity conditions that can change its moisture content. When you bring it into your home, the flooring needs time to adjust to your home's specific temperature and humidity before installation.

This adjustment period is called acclimation.

What Happens Without Proper Acclimation

Gapping

If flooring is installed with a higher moisture content than your home's equilibrium (e.g., it was stored in a humid warehouse and you live in a dry climate), the wood will dry and shrink after installation. The result: gaps between boards.

Cupping

If flooring is installed with a lower moisture content than your home (e.g., very dry flooring installed in a humid home), the boards absorb moisture and expand. Because the floor is attached to the subfloor, this expansion causes the board edges to rise — creating a cupped appearance.

Buckling

In severe cases, expansion from moisture gain in an improperly acclimated floor can be dramatic enough to cause the floor to buckle — planks actually rising off the subfloor. This is expensive to repair.

Warranty Issues

Most hardwood flooring manufacturers require proper acclimation as a condition of warranty coverage. Installing without acclimating and then filing a warranty claim for cupping or gapping is likely to result in denial.

How Long to Acclimate

Acclimation time depends on the flooring type and the differential between the flooring's current moisture content and your home's equilibrium moisture content.

Solid Hardwood

Minimum: 3 days Recommended: 5–7 days In some cases (large humidity differentials): Up to 14 days

Solid hardwood is the most sensitive to moisture because it's 100% wood through its full thickness.

Engineered Hardwood

Minimum: 48 hours Recommended: 48–72 hours In some cases: Up to 5 days

Engineered hardwood's plywood or HDF core is more stable than solid wood, but the real wood surface veneer still moves with humidity changes.

Click-Lock LVP and Laminate

Technically these products don't require acclimation in the traditional sense, but manufacturers commonly recommend:

• Bringing the product to room temperature for 24–48 hours
• Not installing a floor that's been stored in very cold conditions immediately

Modern rigid-core LVP has extremely low moisture movement — but it does expand and contract with temperature. Let it reach room temperature before installing.

How to Acclimate Hardwood Flooring Correctly

Step 1: Prepare Your Home First

Before bringing flooring in, your home must be at its normal living conditions:

• HVAC must be running (heating or cooling, depending on season)
• Target humidity: 35–55% relative humidity
• Target temperature: 60–80°F

Do not acclimate flooring in a space that isn't heated/cooled yet. The flooring will acclimate to the unfinished space and then continue moving when HVAC is turned on.

Step 2: Bring Flooring to the Installation Space

Move flooring boxes into the rooms where they'll be installed. Stack boxes loosely with spacers between them to allow air circulation. Do not stack boxes directly against walls or in sealed piles.

Step 3: Check Moisture Content

If you have access to a pin-type or pinless moisture meter (available at hardware stores or rentable), check both the flooring and the subfloor:

• Flooring moisture content should be within 2% of the subfloor moisture content for solid hardwood
• Flooring moisture content should be within 4% for engineered hardwood

If the differential is greater, extend the acclimation period.

Step 4: Wait

Don't rush this. The cost of an improperly acclimated floor — in repair expense, replacement cost, or voided warranty — far exceeds the inconvenience of waiting a few more days.

Special Situations

Installing in New Construction

New construction homes have elevated humidity from drywall mud, paint, and wood framing that hasn't fully dried. Wait until all "wet work" is complete, HVAC is running, and humidity has stabilized before beginning acclimation.

Installing in Very Dry Climates

In the desert Southwest, homes may have humidity levels below 30% in winter with HVAC running. Very dry conditions require dry flooring (low moisture content). Check actual MC with a meter.

Acclimating Flooring from a Liquidator

Flooring from a liquidator may have been stored in a warehouse with minimal climate control. It's especially important to check moisture content before assuming standard acclimation times are sufficient.

Acclimation and Subfloor Moisture

Acclimation of the flooring is only part of the equation. The subfloor must also be at an acceptable moisture level:

• Wood subfloor: Should read 8–13% moisture content (pin meter)
• Concrete subfloor: Must pass moisture vapor emission testing before any wood-based flooring is installed

High subfloor moisture will cause problems regardless of how well the flooring was acclimated.

The Bottom Line

Acclimation is one of those steps that feels like overkill until you skip it and regret it. A properly acclimated floor installs easier, looks better, and lasts longer. Build it into your project timeline and your floor will reward you with years of trouble-free performance.