Red Seal Drywall Finisher and Plasterer Practice Exam

Which compound is most suitable for creating a smooth finish on drywall?

1. Fast-setting joint compound

2. All-purpose joint compound

3. Thin-set mortar

4. Pre-mixed joint compound

The correct answer is: Pre-mixed joint compound

The most suitable compound for creating a smooth finish on drywall is pre-mixed joint compound. Pre-mixed joint compound is designed specifically for finishing drywall seams and is formulated to provide a smooth, even surface when applied. It has a creamy consistency that makes it easy to spread and manipulate, allowing for a finer finish than other types of compounds. This type of compound typically dries slowly, which allows for better working time and the ability to make adjustments as you level and feather the edges. This property is particularly important when aiming for a smooth finish, as it enables the finisher to sand and smooth out imperfections without rushing through the process. While fast-setting joint compound is useful for quick repairs and initial coats due to its rapid drying time, it does not allow for the same degree of finesse in achieving a smooth finish. All-purpose joint compound can also be suitable for various applications, but it may not provide the same level of smoothness and ease of application as pre-mixed options, especially for the final coats. Thin-set mortar, on the other hand, is not appropriate for drywall finishing, as it is intended for tile setting and does not offer the qualities needed for achieving a smooth drywall surface.