How to Acclimate Flooring Before You Install It

What acclimation does

Wood-based flooring takes up and gives off moisture, and it expands and shrinks as it does. The NWFA says wood flooring simply needs to reach a moisture content in equilibrium with the room, at or near normal living conditions, and that failing to acclimate it may cause excessive expansion, shrinkage, dimensional distortion or structural damage.

The NWFA also notes that some manufacturers do not require acclimation for certain products, and says to always follow the manufacturer on how and whether to acclimate. Your carton's instructions come first; the figures below show what makers write, not a universal rule.

How long, by product type

Laminate: one maker says to let unopened cartons lie flat in the install room for 48 to 96 hours depending on climate, and at least 96 hours in very dry or very humid climates. Cartons should sit at least 2 ft from walls.

Floating luxury vinyl: the instructions we read say 24 to 48 hours at 71 degrees F, with cartons lying flat and out of direct sunlight, and warn that poor acclimation can cause gapping, buckling or joints that will not engage.

Engineered hardwood: one maker requires at least 72 hours at the jobsite, cartons unopened until installation, and 5 days of stable room conditions beforehand.

Solid hardwood: the NWFA gives no number of hours. It says to run permanent heating and cooling for at least five days before installation and to measure moisture rather than count days.

Room conditions that matter

The laminate guide wants relative humidity between 30 and 90 percent and at least 65 degrees F during acclimation and for two days after installation. The engineered hardwood maker wants 60 to 80 degrees F and 35 to 55 percent. The NWFA describes the best range for wood as 30 to 50 percent humidity and 60 to 80 degrees F, with some climates differing.

Do not stack cartons on bare on-grade concrete or against exterior walls. The engineered instructions ask for at least a 4 in air space on or around cartons. Keep them in the installation area, not a garage.

If the permanent heating and cooling cannot run beforehand, the NWFA says a temporary heating or dehumidification system that mimics normal temperature and humidity can let the installation proceed until the permanent system is operating. Use a thermometer and hygrometer in the room so you are working from readings, not guesses.

Checking moisture

For wood, use a moisture meter on the subfloor and on several boards. The NWFA suggests a sample of about 40 boards per 1,000 sq ft. For solid strip flooring under 3 in wide, keep the difference between flooring and wood subfloor to 4 percent or less, and to 2 percent or less for planks 3 in or wider. The engineered maker also says 2 percent and caps wood subfloors at 14 percent.

Write the readings down. The engineered instructions say site tests should be documented because the records matter if you file a warranty claim.

Common acclimation mistakes

The worst case, according to the NWFA, is storing wood flooring on the jobsite in an uncontrolled environment, especially one with excess moisture. It says that does no good and is likely harmful, because the wood adjusts to conditions that the finished room will not have.

Another mistake is counting days instead of measuring. The NWFA's own approach is to take a baseline moisture reading on delivery and acclimate until the flooring is within the allowed difference of the subfloor. Opening cartons early, stacking them on bare slab, and installing before paint, plaster and concrete are dry all undercut the process. The engineered hardwood maker wants new concrete and plaster cured at least 30 days before moisture testing.

Finally, remember that acclimation does not replace the expansion gap. The NWFA notes that on floors wider than 20 ft, row spacing may need adjusting for the climate and time of year, and the engineered maker adds 1/16 in of gap for every 3 ft beyond 25 ft. Acclimate, test, then leave room for movement.

A simple plan

• 1. Finish wet work such as painting and plastering first, and run heating and cooling normally.
• 2. Move unopened cartons into the room, laid flat, away from walls and vents.
• 3. Wait the time in your instructions, longer in extreme climates.
• 4. Meter wood subfloor and flooring, and compare to your maker's limit.
• 5. Open cartons only when you are ready to install, and mix planks from several cartons.

Frequently asked questions

Sources: NWFA Installation Guidelines (copy of the 2007/2008 edition; older than the current edition), Laminate maker Installation Essentials Guide (Pergo), Floating luxury vinyl DIY installation instructions (STAINMASTER, Novalis), Prefinished engineered plank installation instructions (manufacturer PDF). Read 7 November 2026.