RectorSeal Metacaulk® MC 150+ Firestop Sealant – Red, 10.3 oz Cartridge

Protect critical penetrations and construction joints with RectorSeal Metacaulk® MC 150+, a professional-grade intumescent firestop sealant engineered to help stop the spread of fire, smoke, hot gases, and water in fire-rated assemblies. Designed for commercial and residential construction, this versatile sealant provides dependable fire protection while remaining flexible enough to accommodate normal building movement.

Its water-based, non-sag formula is easy to apply using a standard caulking gun and requires no mixing, making installation fast and efficient. Once cured, it forms a durable, paintable elastomeric seal with excellent adhesion to concrete, gypsum board, wood, metal, fiberglass, plastic pipes, and cable penetrations. The flexible formulation is also re-enterable, allowing future modifications without replacing the entire firestop system.

Tested to provide up to 4 hours of fire protection in approved systems, Metacaulk® MC 150+ is an economical solution trusted by contractors for sealing construction joints, pipe penetrations, cable openings, and other fire-rated applications where code compliance and long-term performance are essential.

Key Benefits

• Up to 4-hour fire protection in tested systems
• Intumescent formula helps block fire, smoke, hot gases, and water
• Water-based, non-sag sealant for easy application
• Flexible elastomeric seal accommodates building movement
• Paintable after curing
• Excellent adhesion to concrete, drywall, wood, metal, fiberglass, and plastic
• Re-enterable and repairable for future maintenance
• VOC compliant with mold-resistant protection
• STC Rating up to 65 for improved acoustic performance
• Minimum 3-year shelf life

Recommended Applications

• Fire-rated construction joints
• Through-penetrations in walls and floors
• EMT conduit penetrations
• Metal, fiberglass, insulated, and plastic pipes
• Power, telephone, and data cable penetrations
• Gypsum wall assemblies
• Concrete floors and walls
• Commercial, industrial, and multifamily construction