When humidity conditions are high, which they can be here in Omaha, wood will absorb moisture and swell or expand. To avoid problems, it is recommended that relative humidity be maintained within a range of 35%-50%. Expansion and contraction of the kitchen and bath cabinetry often results from improper humidity levels during site storage, installation, or use. All solid wood is hygroscopic, meaning that when it is exposed to air it will release or pick up moisture until it is in equilibrium with the humidity and temperature climate. As humidity levels increase, wood products will expand due to moisture in the air. In a dry climate home with no humidifier, wood will shrink and expose gaps at the joints. Wood can expand and contract depending on the moisture content, but it does not always move equally or in the same direction. Larger cabinet doors are more prone to warping and center panels may also be affected by shrinkage. Although some cabinets have finishes on them, they will still take in moisture through contact with liquid or absorption through the air. This movement may cause hairline fractures in cabinets or drawers where the wood is joined.
Examples of humidity imbalance include swollen cabinet doors or drawer fronts, butt doors which no longer close properly, door or drawer front panel expansion or contraction, joint separation especially in mitered doors and bowing of rails and stiles. Some hardwoods, such as cherry and maple, are more sensitive to changes in temperature and humidity. Raw or unfinished wood can also show effects of humidity. Small lines in the finish may appear at joinery points if cabinetry is in unstable humidity conditions.
The best way to balance humidity in your home is to make sure that you are consistently running air conditioning, dehumidifiers, and humidifiers if needed to help maintain proper levels of moisture; 35%-50%. During storage of your cabinets, keep them in a room temperature space with temperatures anywhere between 60 and 90 degrees. Before installing your new cabinets, bring them into the space they are going to be installed so the cabinets have time to acclimate to the temperature and environment. Check with manufacturer to ensure that you are keeping your cabinets at the proper level of humidity for their specific cabinets.