Collection: Injection

Cracks in concrete and masonry can be of two types: active (moving) and passive (stable). Active cracks open and close with the structural load cycle — they should be treated with flexible injection material. Passive cracks have stabilized — they can be filled and bonded with rigid, high-strength material. Mixing the two is the most common mistake in injection.

What is injection?

Injection is the process of pressing liquid material into cracks, cavities, and capillaries at low pressure, aimed at restoring structural bonding, preventing water ingress, or blocking capillary moisture movement. The injection material hardens inside the crack and fills the space.

Types of injection materials

Epoxy injection material: The highest strength crack filler. For structural re-bonding of passive, stable cracks — where the two sides of the crack need to be reconnected into a unified structure. Cured epoxy is stronger than the concrete itself. Not suitable for active, moving cracks.

Polyurethane injection material: Available in flexible or foam-forming versions. For active, moving cracks and points of water ingress. PU foam expands upon contact with water and fills the cavity — providing immediate waterproofing. Cures in wet and water-exposed conditions.

Cement-based injection material (suspension): For filling masonry cavities, rock cracks, and capillaries. Low viscosity with good penetration ability.

Micro-cement-based injection material: Finely ground cement that can penetrate narrower gaps where general cement suspension cannot.

Capillary moisture and injection

Injection used against capillary moisture in masonry (so-called horizontal moisture barrier injection) does not fill cracks but blocks the absorption path of capillary moisture. Silane or siloxane-based injection materials seal the capillaries of brick or stone masonry — moisture absorption stops, and the wall gradually dries out.

Browse our injection materials or request advice to select the appropriate injection system for the type of crack and the condition of the structure.