How to Choose the Right Structural Epoxy: Bonding, Grouting, and Crack Repair Explained

When working on structural concrete repairs, structural bonding, or equipment installation, selecting the correct epoxy system is critical to maintaining the long-term integrity of the building. While all epoxy products share base resin properties, substituting one for another simply because they are epoxy-based can lead to structural failure.

To help contractors and engineers select the exact product for their specific site challenges, here is a practical breakdown of four essential Sikadur® structural epoxy solutions:

1. Sikadur®-31 CF: Structural Bonding & Mortar Repair

Character: Thixotropic, non-sag epoxy paste.

Primary Function: Ideal for localized concrete repairs and high-strength bonding between concrete, steel, stone, and brick.

Where to Use: Because of its non-sag consistency, it performs exceptionally well on vertical and overhead surfaces for filling small cavities, structural bonding, and edge repair.

2. Sikadur®-32 LP: Bonding Fresh Concrete to Hardened Substrates

Character: Liquid structural epoxy adhesive.

Primary Function: Acts as a structural bonding agent designed to join freshly placed concrete to existing, hardened concrete surfaces.

Where to Use: Essential for structural extensions, screeds, toppings, and precast concrete elements where a bond stronger than the tensile strength of the concrete itself is required.

3. Sikadur®-42: Heavy-Duty Epoxy Precision Grouting

Character: Three-component, high-strength epoxy grout.

Primary Function: Engineered to absorb heavy dynamic loads, impact, and chemical exposure.

Where to Use: Precision grouting beneath heavy industrial machinery, pump base plates, compressor foundations, and crane rail installations.

4. Sikadur®-52: Ultra-Low Viscosity Crack Injection Resin

Character: Free-flowing, low-viscosity liquid epoxy.

Primary Function: Formulated to penetrate, seal, and restore structural continuity in concrete cracks.

Where to Use: Deep structural crack grouting via gravity feeding or pressure injection systems across slabs, beams, and retaining walls.