A high-performance, high build, chemical, and corrosion-resistant, UL category XKXC2 approved epoxy mastic topcoat optimized for use in Thermo-Lag E100 and Thermo-Lag 3000 series fire resistive applications required to meet class I-A criteria per ANSI/UL 2431. It demonstrates outstanding adhesion and offers maximum protection against severe weather conditions, corrosion, moisture penetration, and general industrial environments.