When adding texture to a wall, the smoothness required depends on the type of texture you plan to apply and your desired final look. Here are a few general guidelines:
Light textures: If you plan to apply a light texture, such as a subtle orange peel or knockdown texture, minor imperfections or bumps smaller than 1mm are typically acceptable. The texture itself can help mask small irregularities and create a more uniform appearance.
Heavy textures: For heavier textures, such as popcorn or heavy stucco, a smoother surface is usually recommended. These textures tend to amplify any underlying imperfections, so it's best to address larger bumps or uneven areas before applying them.
Smooth finishes: If you're aiming for a smooth, flat wall without texture, it's important to achieve a high level of smoothness. In this case, bumps or uneven patches, even those smaller than 1mm, can affect the final look and may be noticeable under certain lighting conditions.
To ensure a satisfactory result, you can take the following steps:
Sanding: After applying the putty and drywall mud, sand the repaired areas using fine-grit sandpaper. This will help to smooth out any larger imperfections. Be sure to feather the edges of the repair to blend them with the surrounding wall.
Prime coat: Apply a coat of primer to the repaired areas and the entire wall. Primer helps to create a uniform surface and provides better adhesion for the texture or paint.
Inspect and touch up: After the primer dries, inspect the repaired areas and the entire wall under different lighting conditions. If you notice any remaining bumps or imperfections that are noticeable or may affect the final look, touch them up with additional putty or drywall mud. Repeat the sanding and priming process as necessary.
Remember, if you're uncertain about your abilities or want to achieve a professional finish, it's always advisable to consult a skilled contractor or professional drywaller who can assess your specific situation and provide expert guidance.