Karnak - 19 Flashing Cement, 3 gallon

Packaged for larger repair jobs, Karnak 19 Flashing Cement in the 3-gallon format is a heavy-duty, trowel-grade compound formulated for long-lasting protection at roof seams, penetrations, and flashings. With its high fiber content and superior adhesion, this asphalt-based cement provides a thick, uniform seal that resists sagging, cracking, and water intrusion—even on vertical surfaces exposed to temperature swings and direct UV.

Key Features

• Thick, trowel-ready consistency that resists sagging
• Forms a tough, weather-resistant, flexible seal when cured
• Ideal for a variety of substrates including masonry, metal, and asphalt
• Available in Summer, Semi, and Winter grades for seasonal conditions

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

• 3 gallon pail - 70/ Pallet
• 1-gallon can - 6 cans/case; 30 cases/Pallet
• 5-gallon pail - 42 pails/Pallet
• 55-gallon drum - 4/Pallet

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

Coverage: approx. 8 gallons per 100 sq ft at 1/8 in thickness

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

Weight per gallon: approximately 8.93 lb (varies slightly among sizes)

Solids: ~77% by weight; ~70% by volume

VOC content: maximum 250 g/L

Compliance: ASTM D‑4586 Type I Class I and Federal Spec SS‑C‑153 Type I

• Clean and dry the surface, ensuring it is free of debris, oils, or frost—especially below 40 °F.
• Apply the cement by trowel to an average thickness of approximately 1/8 in, pressing it firmly into seams or cracks.
• For large or damaged areas, embed reinforcing fabric (such as saturated cotton, fiberglass, or polyester) and cover with an additional coat.
• Smooth the application for even coverage and full substrate contact.
• Allow the repair to cure fully before exposing it to water or foot traffic.
• Clean tools with mineral spirits and perform work in a well-ventilated environment.

Q: What substrates is this cement suitable for?
A: Ideal for use on shingles, masonry, metal, asphalt, flashings, chimneys, parapets, and other exterior surfaces.

Q: What are the application and service temperature ranges?
A: Apply between 40 °F and 120 °F (make sure the surface is dry if below 40 °F). Once cured, the cement performs between 15 °F and 180 °F.

Q: What area does a 3-gallon pail cover?
A: Covers approximately 100 sq ft at 1/8 in thickness (roughly 8 gallons per 100 sq ft usage).

Q: Should I use reinforcement for larger cracks?
A: Yes. Embed reinforcing fabric or mesh before adding another coat for enhanced durability.

Q: Does this product meet recognized standards?
A: Yes—it meets ASTM D‑4586 Type I Class I and Federal Specification SS‑C‑153 Type I standards.