What can be used on a textured surface to ensure a smooth finish before painting?

Using joint compound and a trowel on a textured surface is an effective method to create a smooth finish before painting. Textured surfaces, such as those with stippling or significant irregularities, can interfere with the even application of paint and affect the final aesthetic quality.

Applying joint compound allows you to fill in the indentations and create a flat, even surface. The trowel is the tool that helps to spread and smooth this compound over the existing texture. After the compound is applied and dried, sanding it lightly will help achieve a more refined finish, but the joint compound itself plays a crucial role in transforming the texture into a smooth base.

In contrast, while sandpaper can be helpful for smoothing surfaces, it may not adequately fill deep textures, which is why it is considered less effective for this specific purpose. A paint roller is useful for applying paint but does not aid in preparing a surface for painting. Fabric sheets typically lack the utility needed to achieve a smooth finish on textured surfaces.