Corrosion and fire-induced power degradation are main drivers of extreme financial losses and catastrophic failures in metallic buildings. Polymer coatings function important safeguards in opposition to corrosion; nonetheless, their flammability presents a hearth danger, undermining the general security of the protected construction. Polyvinyl chloride (PVC) displays wonderful inherent barrier properties and flame retardancy, however its poor film-forming means has restricted its sensible utility in high-performance coatings. To deal with this limitation, a core–shell nanostructure hybrid latex was efficiently synthesized by way of seed emulsion polymerization, combining PVC with polyurethane (PU) and polybutyl acrylate (PBA). The ensuing coating displays distinctive anti-corrosion efficiency, demonstrated by a low-frequency impedance modulus (|Z|0.01Hz) exceeding 4 × 1011 Ω cm2 after 30 days of immersion in a 3.5 wt% NaCl resolution, confirming its sturdy and sturdy protecting functionality. Moreover, the cone calorimeter check (CCT) revealed a 7.3% discount within the peak warmth launch fee (PHRR) and an elevated hearth efficiency index (FPI) of 0.079 m2 s kW−1 for the PVC–PU–PBA movie. This work presents a possible and scalable technique for fabricating multifunctional waterborne coatings with built-in corrosion resistance and flame retardancy, providing a promising resolution for superior metal safety.