Gypsum is a general-purpose material, with applications well beyond drywall construction. Construction elements and construction materials based on gypsum are environmentally friendly to manufacture and can be rapidly and inexpensively processed. They create a pleasant indoor climate, regulate interior humidity and always feel pleasantly warm and dry to the touch.
When set, gypsum has two weaknesses, however: it has relatively poor hardness, and is slightly – yet noticeably – soluble in water. The solubility of calcium sulfate dihydrate is roughly 2.6 g/L at 20 °C. Compared to silicate-based building materials, which are practically insoluble in water, this is quite high. Furthermore, gypsum-based construction materials lose their compressive strength when saturated with moisture. Plus, prolonged exposure to water irreversibly damages the material structure.