What type of board is described as being fiberglass mesh reinforced and 7/16" thick?

The type of board that is fiberglass mesh reinforced and 7/16" thick is cementitious backer board. This material is specifically designed for use as a substrate for tile installations. Its structure provides excellent water resistance and stability, making it ideal for areas exposed to moisture, such as bathrooms and kitchens. The fiberglass mesh reinforcement enhances its strength and reduces the risk of cracking, which is critical when supporting heavy tile.

Cementitious backer board is generally preferred over other types of boards for tile installations due to its durability and ability to withstand the expansion and contraction that can occur with temperature changes and humidity. Using this type of board helps to ensure a long-lasting and stable tile surface.