Calcium silicate boards are building materials composed of calcium silicate, a mineral compound made from a mixture of calcium oxide (lime) and silica (sand), along with fibers and other additives. The boards are known for their excellent thermal and fire-resistant properties, as well as their ability to withstand moisture and mold growth. Calcium silicate boards are commonly used in a variety of construction applications, including walls, ceilings, and floors, as well as for insulation and fire protection.