Product Description

The STI SpecSeal® SIL300 Silicone Firestop Sealant is a one-part, neutral-curing silicone firestop sealant designed to control the spread of
fire, smoke, toxic gases, and water in fire-rated walls and floors.
It offers superior water resistance, UV stability, and chemical durability, making it ideal for both through penetrations and construction joints.
Available in non-sag (SIL300) and self-leveling (SIL300SL) grades, it bonds without primers to most substrates and delivers up to 4-hour fire ratings.

Key Benefits

• Fire-Rated Protection – UL Classified; tested to ASTM E814 (UL1479), ASTM E1966 (UL2079), and CAN/ULC-S115.
• Water & Smoke Seal – Class 1 W-Rating, excellent water and smoke resistance.
• Durable & Weather Resistant – Ozone and UV resistant with long service life.
• Dynamic Joint Performance – ±50% movement capability with excellent recovery.
• Primerless Adhesion – Bonds to metals, concrete, masonry, and common building substrates.
• Safe & Sustainable – Non-halogenated, no asbestos or PCB; LEED® compliant, low VOC.

Packaging

• SIL300: 10.1 oz (300 ml) tube, 24/case
• SIL320: 20 oz (592 ml) sausage, 12/case
• SIL305: 4.5 gallon (17 L) pail
• Grades: SIL300 (non-sag), SIL300SL (self-leveling)
• Color: Concrete gray
• Shelf Life: 18 months from manufacture when stored below 80 °F (27 °C)