SpecChem > Products > Specialty Epoxies > Spec CJ Guard

Spec CJ Guard

Water-based, control joint filler stain protectant

Spec CJ Guard is a water-based blend of film-forming polymers designed to prevent or reduce staining of concrete due to overfill of epoxy or polyurea joint fillers. When applied to concrete adjacent to floor joints prior to filling, Spec CJ Guard dries to form a clear, protective film that seals and protects the surface, making the shaving of overfilled joints easier and faster.

  • One-coat application system that is easy to spread and offers excellent coverage.
  • Prevents unsightly stains caused by control joint material overfill.
  • Facilitates easier shaving of joint fillers.
  • Water-based with very low odor and contains 13 g/l VOC.
  • Can be easily removed from concrete and tools with water after joint filling and shaving operations.

Tech Sheet
Safety Sheet


  • Used to protect conventional concrete, polished colored concrete, stained concrete, and other porous surfaces from stains caused by control joint filler overfill.

Surface Preparation:

  • Apply Spec CJ Guard before joint cleaning operations.
  • Ensure the concrete surface is clean, dry, and free from any contaminants such as oil, grease, and curing compounds.
  • The product should only be applied to joints that will be filled the same day.

Application Rate:

  • Coverage rate may vary based on the texture and porosity of the concrete and the type of joint filler used.
  • Typically, 650-800 sq-ft per gallon, depending on application conditions.
  • A test application is recommended to determine the optimal coverage rate.

Application Conditions:

  • Apply only when ambient and concrete temperatures are between 40°F to 90°F.
  • Allow Spec CJ Guard to dry completely before installing joint filler.


  • After joint filler overfill has been shaved, remove the Spec CJ Guard film by saturating with water for 5 minutes, then scrub off any remaining residue.


  • Available in 55-gallon drums, 5-gallon pails, and 1-gallon jugs (4 per case).
  • Clean tools and equipment with water immediately after use.

Test Data

  • Type: Water emulsion
  • Flash Point: Above 212° F
  • Color: Milky Liquid
  • Shelf Life: 1 year


  • Clean tools and equipment with water immediately after use.