What is the minimum period required to apply a finish coat for a three-coat interior plaster after the second coat?

For a three-coat interior plaster system, the minimum period required to apply the finish coat after the second coat is indeed 48 hours. This waiting period is crucial because it allows the second coat to properly cure and harden. Plaster needs time to lose moisture and set adequately; if the finish coat is applied too soon, it can lead to issues such as delamination or poor adhesion, resulting in an unsatisfactory finish.

The curing times are established to ensure that the plaster properly adheres and performs as intended over the long term. A 48-hour wait helps to ensure that the plaster is at a stable moisture level when the finish coat is applied, providing a solid substrate for the final layer.

In this context, shorter waiting periods would not provide adequate curing, which could jeopardize the quality and durability of the finished surface. Therefore, the 48-hour requirement is an essential guideline for achieving the best results in plastering work.