MC-Bauchemie MC-Injekt 2600
Single-component hydrophilic polyurethane injection resin that reacts with water to foam and seal actively leaking cracks, construction joints and pipe penetrations.
What is it?
A single-component, water-reactive polyurethane injection resin from MC-Bauchemie that foams on contact with water to form a flexible, closed-cell seal inside cracks and joints.
Where is it used?
Wet and actively leaking cracks, construction and expansion joints, pipe penetrations and annular gaps in basements, tanks, tunnels, retaining walls and below-ground RCC.
Why use it?
It stops running water where epoxy cannot cure, expands to fill irregular voids, and stays flexible enough to tolerate minor joint movement.
How is it applied?
Injected through packers with a low-pressure single-component pump; the resin meets water in the crack, foams, and cures in place within minutes.
About MC-Bauchemie MC-Injekt 2600
MC-Injekt 2600 is MC-Bauchemie’s answer to one of the most stubborn problems on any waterproofing job: a crack or joint that is not just damp but actively pushing water. It is a single-component, isocyanate-terminated polyurethane prepolymer that stays inert in a sealed container and only begins to react the moment it contacts water during injection. That reaction produces a flexible, closed-cell polyurethane foam that expands roughly 10 to 20 times its liquid volume, driving into the crack, chasing the water back, and setting up an elastic barrier that grips the crack faces.
Because it needs water rather than fearing it, MC-Injekt 2600 is used where conventional rigid epoxy grouts stall. There is no substrate pre-drying, no two-part metering and no fussy pot-life clock — the container life is effectively unlimited until the resin sees moisture. For contractors chasing live leaks in basements, sumps, lift pits, water tanks, tunnels and diaphragm walls, that combination of moisture tolerance, rapid foaming and a flexible cured seal makes it a practical first-line tool. Space Arc supplies it and applies it across Delhi NCR and pan-India, so the material and the injection method arrive together rather than as guesswork on site.
The technical insight
The chemistry does the work. A single-component PU prepolymer carries reactive isocyanate (NCO) groups that are dormant in the pail but hungry for water. When the resin is pumped into a wet crack, those NCO groups react with the free water present — the same water that is causing the leak — releasing carbon dioxide gas. That gas is what inflates the resin into a closed-cell foam, expanding it roughly 10 to 20 times and generating enough pressure to push into hairline branches and to displace standing water rather than trap it. The polymer that forms around those closed cells cures to a flexible elastic solid, typically in the Shore A 20 to 40 range, so the finished seal can absorb the small thermal and structural movements a joint sees without cracking loose. The practical takeaway: the wetter and more active the leak, the faster and more completely the resin reacts, which is exactly the opposite of how a rigid epoxy behaves.
Where it is used
- Sealing actively leaking construction joints in water-retaining and below-ground concrete
- Curtain and crack injection where water is running rather than merely damp
- Sealing around pipe penetrations and service entries through basement and tank walls
- Filling and sealing annular gaps between sleeves, ducts and surrounding structure
- Pre-injection of construction joints ahead of pours to pre-empt seepage paths
- Stop-gap sealing of expansion joint gaps and backing behind joint sealant systems
- Emergency leak stopping in lift pits, sumps, tunnels and diaphragm walls
- Sealing water-bearing cracks in retaining walls, culverts and underground car parks
Key advantages
- Cures with water instead of failing in it — ideal for live, running leaks
- No substrate drying required, so wet cracks can be treated immediately
- Single-component simplicity: no mixing ratios, no two-part metering errors on site
- Effectively unlimited container life until the resin contacts moisture
- Expands roughly 10 to 20 times to fill irregular voids and hairline branches
- Reacts within minutes of meeting water, so leaks stop quickly during injection
- Flexible closed-cell foam tolerates minor joint and thermal movement
- Backed by MC-Bauchemie’s established injection-systems track record
Limitations & considerations
- Forms a flexible foam seal, not a structural bond — it does not restore load transfer across a crack the way a rigid epoxy does
- Best suited to moving or water-bearing cracks; dormant dry cracks needing structural monolithicity are better served by an epoxy grout
- Performance depends on adequate water being present at the reaction front; very dry conditions may need pre-wetting
- Requires proper packers and a low-pressure single-component pump, plus a trained operator to control take-up and pressure
- Foam is sensitive to over-injection — excess pressure or resin can waste material and disrupt the substrate
- Not a substitute for a full waterproofing membrane; it seals discrete leak paths, not whole surfaces
Selection & best practice
Map the leak first and set injection packers along the crack or joint at roughly 500 to 700 mm spacing, angling them to intersect the crack at depth. Flush the crack with water where flow is weak so the resin has moisture to react against, then inject through a low-pressure single-component pump, keeping typical pressure in the 3 to 5 bar range and building it gradually from the lowest packer upward. Watch for resin arriving at the next packer and for foaming at the surface as your cues to move on. Because reaction begins on contact with water, purge and clean the pump and lines promptly after use to avoid resin curing inside the equipment. Treat 2600 as a leak-sealing step: pair it with surface preparation, a durable joint sealant, or a membrane where the design calls for whole-surface waterproofing rather than point sealing.
Specifications
| Product type | Single-component water-reactive polyurethane injection resin |
| Chemistry | Isocyanate-terminated PU prepolymer; moisture-cured |
| Reaction with water | Foams to a flexible closed-cell polyurethane |
| Volume expansion | Approx. 10 to 20 times on contact with water |
| Cured hardness | Approx. Shore A 20 to 40 (flexible / elastic) |
| Mixing | None required — single component |
| Container / pot life | Effectively unlimited while sealed and dry |
| Injection equipment | Low-pressure single-component injection pump with packers |
| Typical injection pressure | Approx. 3 to 5 bar |
| Typical packer spacing | Approx. 500 to 700 mm along crack / joint |
Industry use cases
Basements & underground car parks
Stopping active seepage through construction joints and wall cracks in habitable and parking levels below the water table.
Water & effluent tanks
Sealing leaking joints and pipe penetrations in RCC water-retaining structures without draining or drying the section first.
Tunnels & metros
Curtain and crack injection to control ingress at segment joints, cold joints and diaphragm-wall interfaces.
Sumps, lift pits & STPs
Emergency leak stopping in wet, confined pits where water is running and rigid resins cannot cure.
Infrastructure & retaining walls
Sealing water-bearing cracks and annular gaps in culverts, underpasses and earth-retaining structures.
Frequently asked questions
Does MC-Injekt 2600 stop a crack that is actively leaking water right now?
Is it a structural repair like an epoxy injection?
Do I have to mix anything?
What equipment is needed to apply it?
How much does the foam expand?
Will the seal handle joint movement?
How we position MC-Bauchemie MC-Injekt 2600
MC-Injekt 2600 sits in the leak-sealing end of MC-Bauchemie’s injection range. Where the crack is dormant and needs structural consolidation rather than a flexible seal, the rigid MC-Injekt 2700 / 2700 L polyurethane resins are the family counterpart for cavity filling and soil or void consolidation. Within our wider portfolio, when a customer actually needs a rigid, load-restoring repair we point them to a two-component epoxy injection grout such as Fosroc Nitofill LV; and for permanent joint movement we cross-sell dedicated sealants and expansion-joint systems rather than relying on foam. Positioned honestly, 2600 is the first responder for water-bearing cracks and joints — not a one-product substitute for structural crack repair or full-surface waterproofing.
Fosroc Nitofill UR63 — A specifier already standardised on Fosroc for a project may prefer Nitofill UR63, which is likewise a water-reactive polyurethane for stopping active leaks in cracks and joints.
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