Wood is a fibrous material that can be used in a variety of different practical applications including the construction of structures, furniture and flooring. Because wood is hygroscopic in nature, it absorbs or loses moisture depending on the temperature and the amount of moisture in the air. Wood increases or shrinks in size depending on whether it has reached the equilibrium moisture content (EMC). Wood shrinks as the EMC figure decreases and expands in size as the EMC figure increases.
Expose the wood directly to water to force it to expand. Exposure to modest to moderate amounts of water will cause the EMC to gradually rise and the wood will start to expand. However, soaking the wood in water will cause the wood to expand a tremendous amount.
Raise the humidity of the air around the wood to increase the moisture level in the wood and cause it to expand. As the humidity increases, the wood will absorb the excess moisture in the air and begin to expand.
Cool wood that has been heated by underfloor heaters or other similar heat sources to expand the wood. Just as the wood contracted when it was heated and made dry, the wood will begin to expand as it is allowed to cool and once again absorb moisture.