ASTM standards govern the manufacture of gypsum board and set strict criteria for strength, water resistance, and other characteristics. To produce gypsum board, crushed natural gypsum or synthetic gypsum is heated or calcined to dehydrate the feedstock. Next the calcined gypsum is mixed with water and additives to form a slurry which is fed between continuous layers of recycled paper on a long board machine.
As the board moves down a conveyer line, the calcium sulfate recrystallizes or rehydrates, reverting to its original rock state. The paper becomes chemically and mechanically bonded to the core. The board is then cut to length and conveyed through dryers to remove any free moisture.
End tapes are applied that identify manufacturer, facility, production line, date and time of manufacture as well as country of origin are applied per GA-1000 Identification of Gypsum Board. Ready for installation, the panels are stored and distributed on risers of uniform height to ensure the gypsum panel products are supported evenly. More information on handling and storage of gypsum panels can be found in GA-801-2017 Handling and Storage of Gypsum Panel Products: A Guide for Distributors, Retailers, and Contractors.