18 Perfectseal Flashing Cement (Asbestos Free)

    18 Perfectseal Flashing Cements (Asbestos Free)

    Available in: 3 gallon buckets & 5 gallon pails

    KARNAK #18 Perfectseal Flashing 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 #18 is a durable 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. Available in three consistencies: Summer, Semi and Winter.




    • VOC: 204 g/L


    Coverage Calculator

    • 3-6 Gallons per 100sf**


    This is intended as a general guideline only, coverage can vary based on many factors.


    KARNAK 18 Perfectseal Flashing 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 for pre-cast roof slabs and general purpose use in maintenance of exposed buildings and structures.

    Physical Properties

    1. Consistency: A smooth, heavy trowel consistency which will readily spread on and adhere to surfaces without sagging.
    2. Character of Dried Film: Uniform, excellent adhesion to masonry, steel, cured concrete, shingles, asphalt roofing and a variety of other surfaces.

    3. Has excellent resistance to flow at high temperatures when used on a vertical surface

    Preparation & Application

    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 #18 Perfectseal Flashing 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 #18 Perfectseal Roof Cement over the damaged area, then embed KARNAK Cotton, Glass or Poly-Mat Membrane reinforcement and then apply another coat of KARNAK #18 Perfectseal Roof Cement over the entire patch.

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