Which type of coat should be applied after the 48-hour waiting period in a two-coat plaster system?

In a two-coat plaster system, after the initial coat has been allowed to cure for a 48-hour waiting period, the appropriate coat to apply next is the finish coat. The finish coat provides the final surface texture and aesthetic appearance of the plaster. It is designed to create a durable, smooth surface that is both visually appealing and functional, as it directly influences the longevity and performance of the plastered surface.

The application of the finish coat also plays a critical role in ensuring adhesion with the underlying base coat. This allows for the desired characteristics and properties of the finish, such as color and texture, to be effectively achieved. Additionally, it is formulated to resist moisture, which is especially important in various environmental conditions.

In contrast, the other types of coats mentioned—base coat, scratch coat, and sand coat—serve different functions within the plastering process. The base coat is applied before the finish coat, while the scratch coat is typically the first layer that is applied to provide a rough surface for the base coat to adhere to. Therefore, waiting the specified curing period before applying the finish coat is crucial in achieving a successful and durable plaster finish.