Which material is used as a base for interior veneer plaster finish?

• A. Purple board
• B. Green board
• C. Blue board
• D. Regular gypsum board

Answer: (C)

The appropriate base for an interior veneer plaster finish is blue board. This type of gypsum board is specifically designed for skim coating with plaster because of its unique properties. Blue board has a special moisture-resistant core and a paper facing that is conducive to receiving a plaster finish, allowing it to bond properly.

Using blue board ensures that the veneer plaster adheres effectively, providing a smooth and durable finish that can withstand the stresses of interior application. The board's surface is designed to absorb the moisture from the plaster, which is essential for curing and achieving the desired hardness.

In contrast, while other types of boards like purple or green boards have specific uses, they are not optimal for veneer plastering. Purple board offers moisture resistance primarily for areas sensitive to humidity, and green board is often used in bathrooms because of its moisture resistive properties but lacks the necessary surface for plastering. Regular gypsum board, on the other hand, is not suitable for veneer finishes as it does not have the specialized coating to facilitate plastering applications effectively.