What is the role of primers in improving adhesion on porous surfaces?

• A. Primers seal porosity and improve adhesion.
• B. Primers are only for color tinting.
• C. Primers are unnecessary if you use a topcoat.
• D. Primers are the same as topcoats.

Answer: (A)

Primers seal porosity and improve adhesion. On porous surfaces like wood, plaster, or concrete, tiny pores suck in water and binder, causing the topcoat to dry unevenly and bond poorly. A primer fills and seals those pores, reducing suction and creating a uniform, receptive surface. This gives the topcoat a better grip and a more consistent finish, helping prevent peeling and blisters later. While primers can offer tinting or stain-blocking benefits, their main role here is to seal porosity and boost adhesion. They’re not the same as topcoats, and they’re not just for color.