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CSS-ES Epoxy Primer and Saturant

CSS-ES is a two-component, high-strength, high-modulus epoxy resin system used to prime substrates and saturate the Simpson Strong-Tie® Composite Strengthening Systems™ (CSS) fabrics. When extended with fumed silica, thickened CSS-ES is used as a high-performance substrate repair material and CSS finish coating. This product has been evaluated per ICC-ES AC125 for concrete and unreinforced masonry strengthening using externally bonded fiber-reinforced polymer (FRP) composite systems. This product is NSF-listed safe for potable water. Please refer to the NSF listing for the NSF 61–listed application. This product is part of the tested assembly in UL Design No. N861, which achieved a four-hour fire rating when subjected to ASTM E119 / UL 263 full-scale fire testing. Please refer to UL Online Certifications Directory for the UL listing.

Key Features

  • Long working time
  • High elongation
  • Ambient cure
  • Minimal odor
  • High versatility
  • VOC compliant
  • NSF listed
  • UL listed
  • Component of Class A flame spread/smoke developed indices test


  • Seismic retrofit
  • Load rating upgrade
  • Damage repair
  • Defect remediation
  • Blast mitigation

    Mixing Ratio

    • 2A:1B by volume

    Storage Conditions

    • Store material in a dry area between 45°F (7°C) and 95°F (35°C) with no exposure to moisture.

    Shelf Life

    • 2 years in unopened container


    Kit Size / Model No.

    • 3 US gallon (11.4 L) / CSS-ES-3KT
    • 150 US gallon (567.8 L) / CSS-ES-150KT

    Limited Warranty

    • This product is covered by the Simpson Strong-Tie RPS Product One-Year Limited Warranty, which is available at strongtie.com/limited-warranties or by calling Simpson Strong-Tie at (800) 999-5099

    Related Literature

    Code Reports & Compliance