About MC-Bauchemie MC-Injekt 2K

MC-Injekt 2K is MC-Bauchemie’s two-component polyurethane injection resin for one of the hardest problems a waterproofing contractor faces: a crack or joint that is actively passing water. Conventional coatings and cementitious repairs cannot be applied to a wet, weeping surface, and rigid resins tend to crack again the moment the structure moves. MC-Injekt 2K is formulated specifically for these conditions. It is supplied as two liquids, a polyol base and an isocyanate hardener, that are combined only at the point of injection and react on contact with the water already present in the defect. Instead of fighting the moisture, the chemistry uses it as a trigger.

Once inside the crack, the mixed resin gels quickly and foams, driving itself into fine and irregular flow paths that a single, non-expanding resin would miss. The result is a tough, closed-cell polyurethane that is permanently waterproof yet retains enough flexibility to accommodate the small movements every real structure experiences. For engineers and applicators working on below-ground and water-retaining concrete across Delhi NCR and Pan-India, this makes MC-Injekt 2K a dependable choice when a leak has to be shut off cleanly, without waiting for the structure to dry out or diverting the water first. Space Arc Engineering supplies the resin as an authorised distributor and can carry out the injection work as an applicator.

The technical insight

The material works because it is water-activated rather than water-sensitive. When the polyol and isocyanate components meet in the static mixer and enter a damp crack, the isocyanate reacts both with the polyol and with the water in the defect. That second reaction generates carbon dioxide, which is what drives the foaming and the several-fold volume expansion. Two things happen at once: the resin bulks up to fill the void it is sitting in, and it develops enough internal pressure to push into hairline branches and honeycombed concrete that a flowable, non-expanding grout would bypass. Because the reaction consumes the local water and the foam cells close as they cure, the finished seal is not merely a plug sitting in front of the leak, it is a mechanically keyed mass bonded to the crack faces. The cured polyurethane stays elastic, so when the crack breathes with temperature or load the seal flexes with it instead of debonding. Reaction speed can be biased faster or slower to match how much water is present and how cold the substrate is, giving the applicator control over whether the resin travels further before it sets or locks off almost immediately at a gushing point.

Where it is used

• Stopping active water leaks through cracks in basement raft slabs and retaining walls
• Sealing construction joints and cold joints in below-ground concrete
• Curtain injection behind walls and slabs to form a waterproof barrier against the soil
• Water-ingress control in tunnels, shafts and metro box structures
• Crack sealing in water tanks, sumps and swimming pools
• Sealing leaks around pipe penetrations and service entries
• Remedial injection of honeycombed or porous concrete carrying water
• Filling and sealing segment joints in precast and diaphragm-wall construction

Key advantages

• Cures against flowing or standing water, so leaks can be stopped without first drying the structure
• Foaming expansion drives the resin into fine, branching and irregular flow paths
• Closed-cell cured foam gives a permanently waterproof seal
• Stays flexible after cure, tolerating minor structural and thermal movement
• Adjustable reaction speed lets the applicator tune travel distance versus fast lock-off
• Two-component metered injection gives consistent, reliable mixing on site
• Bonds to damp concrete and masonry substrates
• Suited to Indian below-ground conditions where groundwater is almost always present

Limitations & considerations

• Requires a two-component injection pump with a static mixer and trained operators, it is not a brush or trowel product
• Pot life after mixing is very short, so equipment must be primed and packers set before injection begins
• It seals a crack or joint but does not restore structural strength, use a rigid epoxy where load transfer is the goal
• Best used against water-bearing defects, on a bone-dry crack a water-reactive resin has little to trigger it
• Component ratio, temperature and cleanliness of the mixer all affect the cure and must be controlled
• Isocyanate handling calls for proper PPE and ventilation during application

Selection & best practice

Specifications

Industry use cases

How we position MC-Bauchemie MC-Injekt 2K

MC-Injekt 2K sits in MC-Bauchemie’s resin-based injection range alongside numbered variants such as MC-Injekt 2300 and MC-Injekt 2133, which offer different viscosities and reaction profiles for finer cracks or faster temporary sealing. Where a leak has to be locked off almost instantly before the main injection, a fast-foaming pre-injection resin is often used first, followed by MC-Injekt 2K as the main flexible seal. If the goal is structural crack bonding rather than leak sealing, pair it with a low-viscosity epoxy injection resin instead. Across our other brands, Space Arc can also supply comparable PU and epoxy injection systems from Fosroc and Sika where a specifier standardises on a particular manufacturer.

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