Floor & Joint RepairS olution

Prime Practices

Filling Control Joints with Semi-Rigid Epoxy

Call: 1-800-321-7212

Filling Control Joints With a Semi-Rigid Epoxy Filler

Scope of Work: Cleaning and filling control joints in concrete slabs on grade to prevent edge deterioration.



Concrete slab edge deterioration due to lack of semi-rigid joint filler in control joints.

Surface Preparation

  • Clean joint sidewalls with wet or dry cut saw (dry cut is preferred) with proper dust collection.
  • Saw cut to a minimum of 1”.
  • Clean and remove all dust, water and slurry from the joint.
  • If wet cut, allow joint to dry before installation of epoxy.
  • Make sure all side walls are clean and dust free.


  • Once clean and dry, fill with semi-rigid epoxy (Joint Shield 5000 Epoxy 80A or Joint shield 5100 Caulk Grade), slightly overfilling the joint. Oven-dried sand (Prime Blend) may be used to control seepage.
  • Never use backer rod.
  • Allow material to harden and remove excess material with razor blade or grinder flush with the surrounding floor surface.

Safety Considerations

  • Observe OSHA (or comparable) personal safety guidelines.
  • Carefully read SDS prior to handling any chemical.
  • Always wear safety goggles when drilling, grinding, flushing, injecting or handling resins.
  • Always wear protective clothing, chemical resistant gloves and safety goggles at all times when handling resins.
  • Make sure no loose clothing can come into contact with moving mechanical equipment.
  • Keep first aid kit (eyewash, bandages, etc.) present on site with easy access.

Materials List

  • Epoxy-based joint filler: Joint Shield 5000 Epoxy 80A or Joint Shield 5100 (Caulk Grade) – bulk or in Quick Mix cartridges
  • Prime Eco Flush (pump cleaner)

Equipment List

  • Concrete saw with diamond blades and dust collection
  • FlowMaster pump or the Patriot pump or a positive displacement two-component pump
  • Injection gun if using cartridges (1:1 – 300mL x 300mL)
  • Razor and blades to shave or grinder
  • Clean empty pails
  • Rags
  • Broom


Related Content

Filling Control Joints With Semi-Rigid Polyurea

Repairing Spalls and Chips in Industrial Floors with Prime Bond (epoxy)

Repairing Spalls and Chips in Concrete Floors with Floor Fix (urethane)

Creating a Mortar with Epoxy Resin and Sand for Spall and Joint Repair