18AF Perfectseal Plastic Cement

Karnak #18AF Perfectseal Plastic Cement is a scientifically compounded composition of selected asphalts, mineral fibers, and refined solvents that are manufactured to a heavy consistency. Designed for application by trowel #18AF is a durable, elastic cement with excellent adhesion and weathering characteristics . This product when applied dries to a tough, flexible, water resistant and corrosion proof coating that provides excellent performance over a wide range of temperature and weather conditions.


  • Consistency: A smooth, heavy trowel consistency which will readily spread on and adhere to all surfaces without sagging.
  • Character of Dried Film: Uniform, excellent adhesion to masonry, steel, cured concrete, shingles, asphalt roofing and a variety of other surfaces.
  • Has excellent resistance to flow at high temperatures when used on a vertical surface.


  • ASTM D-4586, Type I ( Free)
  • VOC Content = 300 grams per liter


Karnak #18AF Perfectseal Plastic Cement is a general purpose cement for repairing leaks in shingles, concrete, metal or asphalt roofs, flashings on walls, chimneys, flues, down-spouts and cornices. Excellent for sealing cracks in concrete, brick, as a joint filler forpre-cast roof slabs and general purpose use in maintenance of exposed buildings and structures.


All surfaces should be clean, dry and free from oil or grease, dust, dirt, loose paint or other foreign matter prior to application.


Spread Karnak #18AF Perfectseal Plastic Cement to an average thickness of 1/8" (approximately 8 gallons per square) and press tightly into joints, seams or cracks. To repair large cracks, breaks and blisters, spread Karnak #18AF Perfectseal Plastic Cement over the damaged area, then embed Karnak Cotton, Glass or Poly-Mat Membrane reinforcement and then apply another coat of Karnak #18AF Perfectseal Plastic Cement over the entire patch.


Tools and other equipment should be thoroughly cleaned with mineral spirits, taking necessary precautions when handling combustible materials.


Do not use near heat or open flame. Avoid breathing solvent fumes and prolonged contact with skin. Do not take internally. If swallowed, do not induce vomiting. Call a physician immediately. Keep out of reach of children. Keep container covered when not in use. Do not thin. Dispose of in an environmentally safe manner. Avoid getting in eyes. Use only with adequate ventilation.


Remove to fresh air. Call a physician. If unconscious, give artificial respiration. If splashed in eyes, flush immediately with abundant quantities of running water. Read Material Safety Data Sheet before using this product.


Available in 5 gallon pails and 1 gallon cans.

Translate Site

Kanopy Reflective Roof Maintenance Solutions
  • Reduce Energy Use
  • Lowers Peak Energy Use, reducing energy costs year-round
  • Helps the environment, reduces "Heat Island Effect"
  • Extend the life of the roof
  • Reduces waste. Helps avoid roof tear-off.
  • Economic compared to roof replacement
  • Eliminates interior building operation disruption