Which of the following should be done before applying any finishes to drywall?

Before applying any finishes to drywall, it is essential to sand the surface to improve adhesion. Sanding the drywall helps to create a smoother surface and removes any imperfections, such as joint compound ridges or dust from the installation process. This preparation step enhances the contact between the drywall and the finishing materials, such as paint or texture, ensuring that they adhere properly and provide a uniform appearance.

Sanding also helps in reducing the visibility of seams and joints, which contributes to a cleaner and more professional look once the finishes are applied. Properly prepared surfaces are crucial for achieving the best aesthetic results and long-lasting durability of the finishes.

In contrast, allowing the drywall to dry out completely is important after the installation of joint compound but does not directly relate to the finishing process itself. Installing a vapor barrier is generally necessary for moisture control but occurs at a different stage of the project, often before drywall installation. Similarly, sealing the edges with caulk is a step that can help with aesthetic continuity and moisture prevention, but it is not a main prerequisite for the application of finishes.