What treatment is required for a glossy painted surface before installing reinforcing mesh with compound?

• A. Sand or degloss the surface to ensure proper adhesion of the embedding compound and mesh.
• B. Clean with soap and water only.
• C. Apply a universal primer.
• D. Lightly wet-sand and then wipe clean.

Answer: (A)

Glossy paint creates a smooth, slick surface that won’t hold the embedding compound or the reinforcing mesh. To get a reliable bond, you need to create a rough, keyable surface and remove the glossy layer. Sanding or deglossing achieves this by roughening the surface and eliminating the slick coating, so the embedding compound can grip properly. Cleaning with soap and water alone won’t remove the gloss, leaving a barrier to adhesion. Primers can help in some cases, but they don’t replace the need to key the surface for bonding. Lightly wet-sanding and wiping may help, but it doesn’t guarantee removing the gloss enough to ensure strong adhesion. So the required treatment is to sand or degloss the surface to prepare for the mesh and compound.