MAINTAINING THE CORRECT HUMIDITY LEVEL IN YOUR HOME
(35-50% FOR SOLID AND 30-65% FOR ENGINEERED AND ENHANCED)
Relative Humidity (RH) is the ratio of the actual amount of water vapour contained in the air at a given temperature to the maximum amount of water vapour that the air at that same temperature can hold, expressed as a percentage.
Wood is a hygroscopic material and always contains water. It constantly exchanges water vapour with the air, picking it up when relative humidity is high, and giving it off when relative humidity is low. Since wood swells as it absorbs water, and shrinks as it releases water, both its moisture content and its dimensions are controlled by the relative humidity of the surrounding air. Wood moisture content is equal to the weight of water contained in the wood divided by the oven dry weight of the wood, expressed as a percentage.
Inside homes however, where the relative humidity of outdoor air is drawn inside and drastically altered by heating and cooling without humidification or dehumidification, wide seasonal swings in relative humidity will cause wood moisture content and dimensional changes to occur. Since warm air can hold more water vapour than cold air, the relative humidity of air with a certain absolute humidity can be changed by simply changing its temperature. Gapping and cupping are common results of improper relative humidity and moisture content for solid wood floors. If in winter, for example, outside air is at 20oF and 65% RH is drawn inside and warmed to 70oF without humidification, its relative humidity drops to about 10%. In summer, outside air at 70oF and 60% RH that flows into a basement at 60oF will end up at 82% RH.
Low relative humidity: Solid hardwood flooring installed in a house with low humidity will start to show gaps between the boards. This is strictly a cosmetic issue and does not affect the structural integrity of the product. When the humidity returns to it’s recommended range, these gaps should start to disappear. If the gapping is extreme because the humidity was way below the recommended range, this will take more time to correct itself.
High relative humidity: If the humidity is too high in the house, the most common issue with solid hardwood floors is cupping. This damage can be either temporary (seasonal) or permanent depending on its extremity and the duration of the time it was exposed to high moisture. During this time of high humidity, the floor boards will expand. This expansion can exasperate the gapping during the winter months as the boards will not move back to their original location once they have been forced to move.
Low relative humidity: If the relative humidity is below 30% for a prolonged period, the face lamella will start to contract. This can cause what is called dry cupping and is considered normal when relative humidity is too low. The floor should return to its normal state once the relative humidity is back to normal (30-65%). If the relative humidity drops below 20%, the construction of Superior Engineered Flooring and Enhanced Hardwood Flooring is such that the core material will minimize the face lamella’s contraction. If the lamella is under too much stress, and the core is not allowing the face to move (minimize cupping) the face lamella has no other choice but to relieve its pressure by stress cracking. Stress cracking is NOT covered under this warranty.
High relative humidity: In Engineered and Enhanced Flooring, if the relative humidity is too high, the flooring will start to crown. Once the relative humidity goes back to within the specified range, it can should settle down and return to it’s original state.
DISCLAIMER: Failure to follow these recommendations can and will void your warranty. Refer to our warranty for any more information and exclusions.
Relative Humidity variations can be minimized with proper ventilation, humidification or heating. You may need to improve your humidification and/
or dehumidification system in order to maintain the required humidity levels.
Low relative humidity: If the relative humidity is below 30% for a prolonged period, the face lamella will start to contract. This can cause what is called dry cupping and is considered normal when relative humidity is too low. The floor should return to its normal state once the relative humidity is back to normal (30-65%). If the relative humidity drops below 20%, the construction of Superior Engineered Flooring and Enhanced Hardwood Flooring is such that the core material will minimize the face lamella’s contraction. If the lamella is under too much stress, and the core is not allowing the face to move (minimize cupping) the face lamella has no other choice but to relieve its pressure by stress cracking. Stress cracking is NOT covered under this warranty.
High relative humidity: In Engineered and Enhanced Flooring, if the relative humidity is too high, the flooring will start to crown. Once the relative humidity goes back to within the specified range, it can should settle down and return to it’s original state.
DISCLAIMER: Failure to follow these recommendations can and will void your warranty. Refer to our warranty for any more information and exclusions.
Relative Humidity variations can be minimized with proper ventilation, humidification or heating. You may need to improve your humidification and/
or dehumidification system in order to maintain the required humidity levels.
