Gypsum board entraps what percentage of water?

Gypsum board, commonly used in construction for walls and ceilings, primarily consists of gypsum, a mineral that is composed primarily of calcium sulfate dihydrate. The structural makeup of gypsum includes a significant amount of water, which is chemically bonded to the gypsum. Specifically, gypsum board typically contains about 20% water by weight in its composition.

This water serves various purposes, including enhancing the fire resistance of the board, contributing to its durability, and affecting its insulation properties. The ability of gypsum board to retain this level of moisture is one reason it is considered effective in fire-rated assemblies, as the water content helps to slow down the spread of heat and flames.

The percentage of water content in gypsum board is a crucial aspect for professionals in the construction and fire safety fields, as it influences the material's behavior in fire conditions and impacts the overall performance and longevity of the construction materials used.