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STI SpecSeal WF310 Fire Barrier BlazeStop WF Intumescent Caulk 10oz Cartridge
Latex based, high solids firestop caulk. Seals penetration openings in wood frame construction against the spread of fire, smoke and combustion byproducts. When exposed to elevated temperatures, WF300 expands rapidly to seal off voids left by the burning or melting of combustible materials.
- Expands 5 times original volume
- Will not shrink when dried
- Adheres to common construction materials
$7.82
Availability:
In stock
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SKU
22969
STI SpecSeal WF-310 Fire Barrier BlazeStop WF Intumescent Caulk – 10 oz Cartridge
WF-310 (WF300 series) is a latex-based, high-solids, intumescent firestop caulk for wood-frame construction. It expands when exposed to heat to help seal voids left by burning or melting plastics, forming a durable smoke- and fire-resistant seal around penetrations and joints. The red, paintable sealant installs easily, cleans up with water, and is formulated to be water resistant when dry.
Key Features
- Intumescent firestop caulk for wood-frame floor/ceiling and wall assemblies.
- Expands under heat to help close off voids around combustible penetrants.
- Water based for easy installation and cleanup; water resistant when dry.
- Paintable, non-halogenated, and low VOC.
- High solids formula; won’t separate or shrink when dried.
- Auto-bonding; adheres to lumber, gypsum board, and common penetrant materials.
- Meets Class A surface finish when tested to ASTM E84.
Applications
- Sealing through-penetrations and annular spaces in rated wood-frame floor/ceilings and walls.
- Perimeter gaps and construction joints detailed in tested firestop systems.
- Electrical, plumbing, and HVAC penetrations using tested designs.
- Retrofit resealing during tenant improvements or maintenance work.
Technical Specifications
| Color | Red |
| Chemistry | Latex, intumescent, high solids |
| Free Expansion | Up to 5x original volume under heat |
| Expansion Begins | Approx. 350°F (176°C) |
| Flame / Smoke (ASTM E84) | Flame 0; Smoke 20 (Class A surface finish) |
| STC Rating | 61 (relates to specific construction) |
| VOC Content | Approx. 28 g/L |
| Solids (by weight / volume) | About 81% / 77.6% |
| Density | ~10.2 lb/gal (1.22 kg/L) |
| Application Temperature | 35°F to 100°F (2°C to 38°C) |
| In-Service Temperature | Less than 185°F (85°C) |
| Storage Temperature | 40°F to 95°F (4°C to 35°C) |
| Shelf Life | 24 months from date of manufacture (unopened, proper storage) |
| Compliance | ASTM E814 (UL 1479), CAN/ULC-S115; systems up to 2 hours (wood frame) |
| Unit Size (this item) | 10.1 oz cartridge (300 mL) |
| Case Quantity / Each Weight | 12 per case / ~0.95 lb each |
Frequently Asked Questions
Where is WF-310 used?
In rated wood-frame floor/ceiling and wall assemblies to seal penetrations and joints per tested firestop systems.
Is it paintable and water resistant?
Yes. It can be painted when dry and is water resistant after cure; clean up is with water before curing.
Does it work with plastics?
It is designed to be safe with many plastic pipes and cable insulations. Always confirm compatibility with the penetrant manufacturer.
Any electrical precautions?
The wet sealant is conductive until dry. Do not apply in the presence of exposed or energized conductors.
What certifications does it meet?
Tested to ASTM E814/UL 1479 and CAN/ULC-S115; Class A surface finish when tested to ASTM E84.
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