Gypsum board is widely used by the construction industry for internal walls and ceilings. Atlas Coated Facers that are designed for gypsum wallboard are typically constructed of glass fiber wet process mat coated with a highly filled inorganic coating. The glass mat serves as reinforcement for the coating, and also the end product wallboard for improved strength and dimensional stability. The coating prevents bleed through during board manufacturing, but provides enough vapor transmission to prevent blistering during drying of the board. The end product wallboard offers a strong durable board with good weatherability and dimensional stability. Testing of GCF facers shows it will not support the growth of mold and mildew.