Before anyone gets cracking on installing new wood floors however, two very important facts of wood must be understood. The first and foremost rule is that wood moves even after it is installed into flooring, wood continues to "breathe", so to speak, taking in and releasing moisture into its cells. This moisture transfer results in swelling and shrinking, which can be hardly noticeable, or very damaging if a inexperience wood floor installer take care for your flooring installation. In Oakland Wood Floors, we make sure we always have the acclimation time for any new floor installation and this warranty ensures you will not have a problem in the future.
Now knowing this, it is also important to understand the second rule: Nothing can stop this movement entirely, but generally that is months after a new installation. You may hear a strong crack in the floor every now and then when the material is expanding or contracting. This usually settles after a full year or after the wood floor been exposed to all four weather seasons .
It appears that wood swells and shrinks across its width, but not a substantial amount along its length. This has to do with the longitudinal structure mentioned above, similar to a bundle of straws. At equilibrium, the bundle of straws stands up straight. During instances of high humidity, the bundle will cinch at the middle and create pressure, but expand at the ends. In instances of low humidity, the bundle will shrink and constrict. The length, however, remains virtually unchanged in all of these scenarios.
One of the worst types of movement is warp, which is the expansion or contraction in uneven patterns which deforms the original shape of the sawn or milled wood floor board. Warping mostly occurs during the initial drying stage because the wood is shrinking at a rapid rate; however, it can continue after the wood is dry. Much of wood movement can be limited though, depending on how your wood is cut. Between plainsawn, riftsawn, and quartersawn, the best bet is the latter. It is the most dimensionally stable material and provides the most even movement along the annular rings, decreasing the chance of warping. Also, a smart woodworker would choose a dry or "seasoned" wood for their project because it has been properly dried and retains an acceptable moisture content.
This minimizes unpredictable hardwood floor movement and warp or cupping in your wood floors.
Depending on the project, wood movement can also be controlled by designing the floor to allow the movement. For example, leaving a 1/2" gap between the floor and the wall lets the wood expand and contract without putting stress on the other wood floor boards. On the other hand, gluing a frame floor with inadequate acclimation time will eventually result in some kind of failure, which can break the floor boards joints or split the paneljoints. Making sure the room is the proper relative humidity (RH), and not too high or low, will prevent expansion or contraction is recommended to acclimate your new wood floors for at least 1 week inside the property with an average temperature.
Multiple coats of a good wood floor finish will help keep moisture from releasing from your wood floor or from entering it.