Epoxy Crack Injection

Understanding Epoxy Crack Injection

Epoxy crack injection uses ports installed along the length of a crack, sealed at the surface with a paste, then filled with a low-viscosity epoxy resin pumped in under pressure. The resin flows into the full depth and width of the crack, including hairline branches that a surface-level patch would never reach, and cures into a rigid bond between the two crack faces.

What Determines If a Crack Should Be Injected?

Whether a crack is actively moving matters most. A stable, non-moving structural crack is a good candidate for rigid epoxy injection, since the repair will hold as long as the crack does not open further. A crack that is still moving due to settlement or seasonal expansion is usually better served with a flexible polyurethane or polyurea injection, which can accommodate ongoing movement instead of cracking again next to the epoxy repair.

Epoxy Crack Injection vs. Surface Patching

Surface patching fills only the visible opening at the top of the crack with a mortar or sealant, which can hide the crack cosmetically but does nothing to reconnect the concrete below the surface. Epoxy injection fills the crack through its full depth, restoring load transfer across the crack and making it a true structural repair rather than a cosmetic fix.

Practical Tips for Epoxy Crack Injection Projects

Confirm whether the crack is still active before choosing epoxy over a flexible injection resin, since injecting a moving crack with rigid epoxy often leads to a new crack forming right next to the old repair. Space injection ports closely enough to ensure full resin coverage along the entire crack length, especially on wider or deeper cracks. Grind or coat over the repaired area once it cures, since the cured epoxy bead is stronger than the surrounding concrete and can telegraph through certain floor finishes if left exposed.