Karnak - 19 Ultra Rubberized Flashing Cement 1 Gal Wet/Dry, Emergency Repair

Karnak 19 Ultra Rubberized Flashing Cement in the 1-gallon pail is a professional-grade, rubber-reinforced asphalt sealant designed for long-lasting emergency and general roof repairs. Its ability to adhere to both wet and dry surfaces makes it ideal for sealing flashing, seams, skylights, and penetrations in demanding weather conditions.

Key Features

• Rubberized elastomeric formulation for superior flexibility and durability
• Wet or dry application, even sticks under water on the first build
• Excellent adhesion and resistance to sag at elevated roof temperatures
• Available in Summer, Semi, and Winter grades, ready to apply—no mixing needed

Packaging: 1‑gallon can (also offered in 3‑gallon buckets, 5‑gallon pails, 55‑gallon drums, and 10.1 oz cartridges)

• 1-Gallon Can = 6 Cans/Case; 30 Cases/Pallet
• 3-gallon Bucket = 70/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 under 40 °F)

Coverage: approximately 8 gallons per 100 sq ft at 1/8‑inch thickness (one coat)

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

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

Weight per gallon: ~8.77 lb

VOC content: maximum 270 g/L

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

* This item is hazmat *

• Clean and dry the surface, removing dust, dirt, grease, or loose material; excess moisture should be minimized for optimal results.
• Apply the flashing cement with a trowel at roughly 1/8‑inch thickness (about 8 gallons per 100 sq ft), pressing firmly into seams, cracks, or joints.
• For larger or deteriorated areas, embed reinforcing material such as saturated cotton fabric, fiberglass membrane, or polyester mat, then apply another cement coat over the patch.
• Smooth the surface uniformly and allow it to cure fully before exposure to moisture or foot traffic.
• Clean tools with mineral spirits and work in a well-ventilated area.

Q: What sets 19 Ultra apart from standard flashing cement?
A: Its rubberized, elastomeric formula maintains flexibility, resists sag, and can bond to wet surfaces—ideal for challenging repair conditions.

Q: Can I use it when the roof is damp or during rain?
A: Yes—its built-in water-displacing agents allow adhesion even to wet surfaces, though cleaner surfaces improve performance.

Q: How much area will one gallon cover?
A: Approximately 100 sq ft at 1/8-inch thickness per single coat.

Q: Do I need to reinforce large repairs?
A: Yes—embedding fabric or mesh into the cement and topping with a second coat enhances durability.

Q: Is it compliant with major standards and temperature flexible?
A: Yes—it meets ASTM D-4586, D-3409, and SS-C-153 Type I, and remains effective from 15 °F to 180 °F.