What is the total thickness required for the first two coats over plasterboard?

The total thickness required for the first two coats over plasterboard is determined by the standard practices in drywall finishing. Typically, the initial coats—that comprise a taping coat and a second coat—are constructed to a total thickness of about 1/2 inch when considering the thickness of the joint compound being applied. This thickness provides sufficient coverage to create a smooth and even finish over the seams and fasteners of the plasterboard.

By combining a taping coat and a second coat, the final finish achieves the right amount needed to ensure durability and an aesthetically pleasing surface. Using more than 1/2 inch could lead to issues such as excess weight and extended drying times, while a thickness under 1/2 inch may not sufficiently cover imperfections or seams, leading to a compromised finish.