Dr. Fixit Inject PU 200
A fast-reacting, two-component PU foam injection grout that shuts off actively gushing water in dams, tunnels, basements and foundations — engineered to react whether the crack is wet or dry.
What is it?
A two-component, fast-reacting hydrophobic polyurethane (PU) injection grout that expands into a rigid, closed-cell foam within seconds of mixing — built to cut off actively flowing water rather than just seal a static crack.
Where is it used?
Leaking dam galleries, subway and tunnel linings, diaphragm and retaining walls, basements, foundation stabilisation and any construction or expansion joint where water is actively gushing through concrete.
Why use it?
It reacts and expands whether or not water is present, penetrates hairline cracks at under 400 cP mixed viscosity, bonds to wet and dry concrete alike, and is non-toxic to aquatic life — so it can be used even close to drains and water bodies.
How is it applied?
Base and hardener are pumped in equal parts (1:1 by volume) through a twin-component injection pump with a static or dynamic mixer at the gun tip, and injected through packers drilled into the crack or void; foaming starts within 15 seconds of mixing.
About Dr. Fixit Inject PU 200
Dr. Fixit Inject PU 200 is Pidilite’s two-component polyurethane injection grout for one specific, high-pressure job: stopping water that’s already moving through concrete. Mix the resin and hardener 1:1 by volume at the gun tip and the two react almost instantly — cream time under 15 seconds, rise time under 20 — expanding more than 16 times its liquid volume into a hydrophobic, closed-cell PU foam. Because the chemistry reacts in the presence or absence of water, it doesn’t need a dry substrate or a slow-curing window the way an epoxy does; it foams and seals even while water is pushing through the crack it’s been injected into, which is exactly the scenario dam galleries, tunnel linings and flooded basements throw at contractors.
On Indian sites this is the product you reach for after a monsoon basement-seepage call, or ahead of a metro or tunnel drive where pre-excavation grouting has to consolidate loose, water-bearing ground before boring continues. It’s an injection-only system — it needs a twin-component metering pump with a static or dynamic mixer, packers drilled into the crack, and someone who has actually run one before, so Space Arc supplies it alongside application by our own trained crews rather than as an over-the-counter tin. As an authorised Dr. Fixit distributor and applicator across Delhi NCR and pan-India, we stock both the 5 kg and 20 kg kits and can turn around emergency water-cut-off jobs — lift pits, cable trenches, leaking construction joints — on short notice.
The technical insight
The “hydrophobic” tag matters more than it sounds. Hydrophilic PU foams absorb water after they cure and keep swelling — useful for some gasket applications, but they can shrink back once water pressure drops and re-open a path. Inject PU 200’s hydrophobic, closed-cell structure (over 90% closed cells per the TDS) cures to a fixed, rigid-to-semi-rigid mass — Shore A hardness ≥ 30, Shore 00 ≥ 70 — so once it sets it stays set, and its bond strength of over 0.8 N/mm² (ASTM C882) to both wet and dry concrete means it’s actually gripping the substrate rather than just plugging the hole. The sub-400 cP mixed viscosity is what lets a single injection reach both the macro-crack the packer sits in and the hairline fissures branching off it, instead of just bridging the visible gap.
Where it is used
- Sealing gushing water leaks in dam galleries, spillway joints and retaining walls under high hydrostatic pressure
- Pre-excavation grouting ahead of tunnel boring / NATM drives to consolidate loose, water-bearing ground
- Stopping active seepage through leaking construction joints and cold joints in basements and water-retaining structures
- Foundation stabilisation by filling voids beneath footings and loose sub-grade soil
- Fissure and crack grouting in concrete without inducing further structural movement
- Emergency water cut-off in lift pits, sumps, cable trenches and underground utility chambers
- Void-filling behind tunnel and subway linings and shotcrete sections
Key advantages
- Reacts and cures in the presence or absence of water — works even while a leak is actively flowing
- Very fast reaction profile (cream time under 15 seconds, tack-free under 100 seconds) so it foams and sets before high-pressure water can wash it out
- Low mixed viscosity (under 400 cP) penetrates macro-cracks and hairline fissures alike
- High volumetric expansion (over 16 times) fills voids economically with a small material quantity
- Bonds strongly to both wet and dry concrete and stone (>0.8 N/mm² per ASTM C882)
- Cures to a rigid, fine, closed-cell foam (>90% closed cells) that resists water re-entry rather than staying spongy
- Tested non-toxic to aquatic life (zebra fish, IS 6582 Part 2), so it’s usable close to drains and water bodies
Limitations & considerations
- Strictly an injection product — needs a twin-component metering pump and a trained operator, not a DIY cartridge job
- Instant foaming (under 30 seconds after mixing) means mixing has to happen at the gun tip; any delay in the line risks a blocked mixer
- Below 15°C, both product and equipment need to be conditioned above 30°C for at least 3 hours before use, adding site prep time
- Moisture-sensitive in storage — packs must stay sealed and dry, and shelf life is a relatively short 12 months from manufacture
- Stops water and stabilises voids but isn’t a structural crack-bonding resin like an epoxy — dry structural cracks are usually better served by an epoxy injection system
Selection & best practice
Always mix a small trial batch on site to check foam time and foam quality at the day’s ambient temperature before committing to the injection run — cream and rise times shift with heat, humidity and equipment condition. Below 15°C, condition both product and injection equipment above 30°C for a minimum of 3 hours first, or the foam won’t rise or cure to spec. Space packers to suit the crack width and expected penetration depth, and control injection pressure to the structure’s condition — too aggressive a pressure on a weak or thin section can do more harm than the leak itself. Because the product foams in under 30 seconds once mixed, mixing has to happen at the gun tip through the inline mixer, never in a pot beforehand, and it should never be diluted with water or solvent to stretch a pack. Clean the pump and lines with thinner or solvent immediately after the job — cured PU left inside a gun is a write-off, not a clean-up job.
Specifications
| Chemistry | Two-component hydrophobic polyurethane foam (base resin + hardener) |
| Mixing ratio | 1:1 by volume (base : hardener) |
| Density, mixed | < 1.25 g/cm³ (ASTM D1475) |
| Viscosity, mixed | < 400 cP (ASTM D2196) |
| Volumetric expansion | > 16 times |
| Reaction profile @ 28°C ± 2°C | Cream time ≤ 15 sec; rise time ≤ 20 sec; tack-free < 100 sec; set time ≤ 10 min |
| Bond strength | > 0.8 N/mm² (ASTM C882) |
| Hardness | Shore A ≥ 30; Shore 00 ≥ 70 (ASTM D2240) |
| Pack sizes | 5 kg kit (2.3 kg base + 2.7 kg hardener); 20 kg kit (9.5 kg base + 10.5 kg hardener) |
Industry use cases
Metro & tunnelling
Pre-excavation grouting ahead of TBM/NATM drives and sealing water-bearing ground and lining joints on Delhi NCR metro and underground infrastructure projects.
Dams & hydropower
Sealing leaking galleries, spillway construction joints and gate seals under high hydrostatic head in dam and irrigation structures.
Basements & below-grade structures
Emergency shut-off of active seepage through construction joints, cold joints and wall-to-slab junctions during monsoon water-table rise.
Foundations & underpinning
Stabilising loose, voided or water-bearing sub-foundation soil before underpinning or load-transfer work.
Utility & industrial structures
Void-filling and water cut-off around leaking sumps, lift pits, cable trenches and underground utility chambers.
Frequently asked questions
Does the crack or joint need to be dry before I inject Dr. Fixit Inject PU 200?
What equipment do I actually need to apply it?
How is this different from an epoxy crack-injection resin?
How much area or crack length will one 5 kg kit cover?
Is it safe to use this close to a drain, sump or water body?
What’s the shelf life, and how should we store unused stock?
How we position Dr. Fixit Inject PU 200
Within the Dr. Fixit range, Inject PU 200 sits at the “active water leak” end of the repair line-up — pair it with Dr. Fixit Crack X Shrinkfree for surface-level shrinkage cracks that aren’t leaking, Dr. Fixit Pidiproof LW+ as an integral waterproofing admixture for new concrete pours, or Dr. Fixit Raincoat WPC on the exterior envelope once the structural leak is sealed. For specifiers comparing brands, the closest genuine equivalent is Fosroc Nitofill PU23, a similarly water-reactive two-component PU injection resin built for the same actively-leaking-crack scenario; MC-Bauchemie’s MC-Injekt 2K PU and Sika’s Injection-101H / Injection-201 IN cover comparable ground too, so the choice usually comes down to site relationships, pump compatibility and stock availability rather than any large performance gap between them. As an authorised Dr. Fixit distributor and applicator, Space Arc stocks Inject PU 200 alongside the Fosroc Nitofill range, so we can specify whichever fits the project and the client’s existing brand preference.
Fosroc Nitofill PU23 — A specifier already standardised on Fosroc, or needing a documented two-component water-reactive PU injection resin under a Fosroc TDS for a metro or dam contract, would reach for Nitofill PU23 instead — it targets the same actively-leaking-crack scenario as Inject PU 200.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.