Hydroscopic refers to materials which absorb water or describes the experience of materials which absorb water. For example, granite and porcelain do not absorb water by an easily measurable means. In contrast, carpet, hardwood, laminate, and drywall are all hydroscopic. That is, they all absorb moisture. The air's relative humidity will cause hydroscopic materials to swell or contract. Therefore, hydroscopic flooring products need to achieve the equilibrium moisture content (EMC) before installation. Maintaining your HVAC system is important for equilibrium.