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Sealants
Metacaulk 835+ Firestop Silicone Sealant
Single component, low modulus, non-slumping silicone firestop sealant. Up to 3-hour fire resistance. Resistant to UV, ozone, and cracking. Class 25 movement capability (ASTM C920). Suitable for interior and exterior applications. Available in caulk, self-leveling, and spray.
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UL-Classified SystemsComponents of tested UL firestop systems
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Authorized DistributorGenuine Metacaulk® / RectorSeal
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TDS & SDSFull technical documentation
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Same-Day ShippingOrder by 11 AM CST
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Spec & Submittal SupportCode & system help
Key features
- UL Classified systems up to 3 hours
- Silicone-based, Class 25 movement (ASTM C920)
- UV, ozone, and weather resistant — interior/exterior use
- STC Rating 55, 600% elongation
- 2-year shelf life (18 months for spray)
- Flame Spread 3, Smoke Index 22
Typical applications
- Metallic pipes
- insulated pipes
- insulated air ducts
- single & bunched cables
- cable trays & bus bars
- construction joints
- perimeter fire barriers
Technical data
| VOC | 0.22 mg/m³ |
|---|---|
| Color | Gray |
| Application Temp | -20°F–120°F |
| Chemical Base | Silicone Base, Neutral moisture cure |
| Cure Time | 21 days |
| Hardness | Shore A 35 |
| Skin Time | 10–40 min @ 77°F |
| STC Rating | 55 |
| Viscosity | 40,000 cp |
| Elongation | 600% |
| Smoke Index | 22 |
| Flame Spread | 3 |
| Service Temp | -60°F–300°F |
| Joint Movement | ±25% (ASTM C920) |
| Specific Gravity | 1.33 g/cm³ |
Installation overview
- Clean all contact surfaces free from debris and contaminants
- Install required backing material per system design
- Apply Metacaulk 835+ ensuring contact with all surfaces
- Caulk: Tool to a defect-free finish. Spray: Apply to specified thickness with 1/2" minimum overspray
- Clean all equipment immediately after use