Interior primers are generally used with latex paints to cover old layers of paint or wallpaper. They have lower VOCs than exterior paints, making them safe to use indoors, and contain rigid resins, so they are less prone to damage from scuffing.

Exterior primers contain additives that help prevent fading and rust, repel moisture, stop oxidization and mildew, and resist staining. Exterior also help restore already-rusted objects and prepare them for topcoat paints.

Exterior primers are flexible to prevent them from cracking or splitting when the surface underneath expands and contracts. They are commonly used on siding, trim, doors, roofs, gutters, porches, and pools in preparation for topcoat painting.

Galvanizing primers add a light zinc coating to metal materials to help resist rust and moisture. The galvanized coating has extra resin that bonds to topcoats to prevent splitting or cracking.

Rust-converting or rust-reforming primers cover rusted objects to solidify and restore finishes. The resins in the primer bond to the rust turning it black, allowing it to be painted like new.

Rust inhibiting or rust preventive primers seal out moisture and mold from objects to prevent rust from forming. These inhibitors prevent paint from cracking or peeling.