Karnak - 19 Ultra Rubberized Flashing Cement 3 Gal Wet/Dry, Emergency Repair

The Karnak 19 Ultra Rubberized Flashing Cement in a 3-gallon pail is ideal for large-scale or long-term roofing repair projects. Engineered to stick in both wet and dry conditions, this heavy-duty formula seals leaks and penetrations quickly, maintaining flexibility and weather resistance over time. Designed for trowel-grade applications across a variety of roofing materials.

Key Features

• Rubberized elastomeric formulation for superior flexibility and durability
• Bonds to wet or dry surfaces, even under damp conditions
• Provides excellent adhesion with resistance to sag at high roof temperatures
• Offered in Summer, Semi, and Winter grades for seasonal applications

Packaging: 3-gallon Bucket (also available in 1-gallon cans, 5-gallon pails, 55-gallon drums, and 10.1 oz tubes)

• 3-gallon Bucket = 70/Pallet
• 1-Gallon Can = 6 Cans/Case; 30 Cases/Pallet
• 5-Gallon Pail = 42 Pails/Pallet
• 55-Gallon Drum = 4 Drums/Pallet

10.1 oz tube = 48 Tubes/Case; 32 Cases/Pallet

Application temperature: 40 °F to 120 °F (substrate must be dry if below 40 °F)

Coverage: approximately 8 gallons per 100 sq ft at 1/8-inch thickness

Service temperature (cured film): 15 °F to 180 °F

Weight per gallon: ~8.8 lb

Solids: ~74% by weight; ~66% by volume

VOC content: up to 270 g/L maximum

Compliance: ASTM D-4586 Type I (Class I & II), ASTM D-3409, Federal Spec SS-C-153 Type I

* This item is hazmat *

• Clean and prepare the substrate, removing debris, dirt, grease, and standing water.
• Apply the cement with a trowel at about 1/8-inch thickness, pressing firmly into cracks, joints, and seams.
• For larger repairs, embed reinforcing fabric such as fiberglass mesh or polyester mat, then apply a second coat.
• Smooth the surface for uniform adhesion and finish.
• Allow the repair to cure before subjecting to heavy moisture or traffic.
• Clean tools immediately with mineral spirits and work in a ventilated area.

Q: What makes 19 Ultra different from standard flashing cement?
A: Its rubberized elastomeric formulation gives it superior flexibility, sag resistance, and adhesion to wet surfaces compared to traditional cements.

Q: Can I apply this in damp weather?
A: Yes. Its water-displacing formulation allows bonding to damp or wet surfaces, though preparation always improves results.

Q: How much area does a 3-gallon pail cover?
A: At 1/8-inch thickness, coverage is approximately 100 sq ft per 8 gallons applied.

Q: Do I need to reinforce larger areas?
A: Yes. For large cracks or breaks, embed reinforcing fabric before applying a second coat to maximize durability.

Q: What is the service temperature range once cured?
A: The cured film performs continuously between 15 °F and 180 °F.