Many homeowners are not aware of how humidity affects wood floors until they experience it first hand. Oftentimes, the wood floor installer has laid the floorboards too quickly and skipped a critical first step. This step is known as acclimating your wood floor. This procedure is important for all varieties of wood floors like hardwood, prefinished and engineered.
Before laying a wood floor, you want to measure the moisture content of the atmosphere in the room where the floor is being laid as well as the floorboards themselves. This can be done with a hygrometer or a moisture meter. This can be purchased online or at your local electronics store. Stay away from the cheap metal ones. They will not give you an accurate moisture reading. They should be close in their moisture content (MC). You should measure the moisture content over the span of a few days to notice any fluctuations and to get a more accurate reading. Typically, 72 hours or 3 days should do the trick.
If they are not close, you should not be laying your floor yet. Instead, you should be letting them sit in the room allowing them to reach the relative humidity of the room. You need to be patient at this time. If you rush, chances are you will have warped floorboards in the future. If your flooring contractor insists on laying your floorboards right away, personally I would question his workmanship. With all varieties of wood floors, you need to acclimate. This is never an instant process. Besides, chances are that when you receive your floorboards, they are coming off a boat that has been on the ocean for awhile coming from a faraway place like Asia. You have no idea what the moisture content of the wood is at and it will probably take some time to adjust and acclimate.
The floorboards have to become accustomed to and reach an equilibrium of the relative humidity (RH) level of your house. This may take as much as several weeks to reach a moisture reading of 9 or 10% in a climate like Florida and with solid wood floorboards. This will prevent moisture damage in the future. You should never bring your wooden floorboards home and install them right away. It is asking for immediate shrinking or swelling, depending on the humidity level of your house and the time of year.
If acclimated correctly, the floor will not shrink or swell once it is installed. This is only true if you are responsible and make sure that the atmospheric humidity of your home does not fluctuate significantly. You should put your floorboards in a room with 1 percent more than the intended equilibrium moisture content (EMC). The EMC is when the wood is not going to absorb or lose any more water. The room should also have some fans to move the air throughout the room. If the floorboards are too wet, you can correct this by putting them in a room that has 1 or 2 percent less moisture than the intended moisture level.
It is up to you to keep your relative humidity consistent and stabilize your indoor environment. Keep your wood floor beautiful! Also, think twice before getting a wood floor in your kitchen and bathroom. These are two rooms in your house that will always have water problems. No matter how well you have acclimated your boards, you will just be asking for trouble.
I suggest reading my article, "The Science Behind Moisture and Wood Floors" to learn about how and why wood reacts to humidity.