Sika Injection-101 RC
A fast-foaming, water-reactive polyurethane injection resin that shuts down live water ingress in cracks, joints and cavities, then sets the stage for permanent sealing.
What is it?
A two-part, low-viscosity polyurethane injection resin that reacts on contact with water and foams into a dense, flexible mass to stop active leaks.
Where is it used?
Wet cracks, construction joints and voids in concrete and masonry, plus specialist work on bored/sheet-pile walls, anchor heads and micro-tunnels.
Why use it?
It works precisely where epoxy fails, in running water, expanding up to 40 times to block flow within seconds so structural repair can proceed dry.
How is it applied?
Pump-injected through packers into the leaking crack, either mixed 1:1 or run as a single-component system, so the foam cures against the incoming water.
About Sika Injection-101 RC
Sika Injection-101 RC is the material engineers reach for when water is already pouring through a crack and the repair simply cannot wait for the substrate to dry. It is a two-part, solvent-free polyurethane resin with a very low mixed viscosity, which lets it travel deep into hairline cracks and fine joints before it does its work. The moment it meets water, the chemistry triggers: the resin foams rapidly, expanding up to forty times its liquid volume, and the growing cellular mass presses outward against the crack walls to physically choke off the flow. Because it is designed for hot and tropical climates, it holds up to the ambient conditions common across Delhi NCR and the rest of India.
It is important to be honest about what this product is for. Sika Injection-101 RC delivers a temporary water stop, not a permanent structural seal. Its role is to arrest high-pressure infiltration quickly and buy a dry working window. Once the leak is controlled, the same holes are re-injected with a permanent resin such as Sika Injection-201 CE or Sika Injection-203 to lock the repair in for the long term. Understood in that two-stage logic, it is one of the most dependable first responders a waterproofing crew can carry, and Space Arc Engineering supplies it as an authorised distributor alongside the accelerator and permanent resins that complete the system.
The technical insight
The performance comes from a water-reactive polyurethane prepolymer. In a dry crack the resin stays liquid and mobile, which is why the low viscosity (Part A around 140 mPa·s, Part B around 155 mPa·s at +20 degrees C) matters so much: it penetrates before it reacts. When the resin contacts water, an exothermic reaction generates carbon dioxide gas that blows the polymer into a fine-celled foam. Under EN 1406 at +20 degrees C, expansion begins roughly 15 seconds after water contact and completes around 67 seconds later, giving the crew a controlled, predictable set. In colder conditions below +10 degrees C the reaction slows, so Sika Injection-AC10 is dosed in by weight to bring the expansion start back down, at 5 percent it drops the start to around 10 seconds at +20 degrees C. The cured foam is flexible rather than rigid, which lets it tolerate minor movement and wet-dry cycling in the joint while it holds back water until the permanent resin is placed.
Where it is used
- Emergency stopping of high-pressure water intrusion through live cracks in concrete and masonry
- Sealing leaking construction joints, cold joints and cavities in basements and water tanks
- Waterstopping in tunnels, shafts and micro-tunnelling operations
- Pre-injection to dry out a crack before a permanent resin seal is placed
- Sealing around bored piles and sheet-pile walls where groundwater is pushing through
- Treating anchor heads and penetrations that are actively weeping
- Curtain and void-filling injection behind leaking retaining structures
- First-response leak control in dams, reservoirs and below-grade car parks
Key advantages
- Reacts only on contact with water, so it works in wet, flowing cracks where epoxy injection cannot
- Very low mixed viscosity penetrates fine cracks and hairline joints before foaming
- Rapid, free-foaming expansion up to 40 times its volume for fast, positive leak control
- Can be run as a single-component system, simplifying pump setup on site
- Adjustable reaction speed using Sika Injection-AC10 for cold-weather work
- Solvent-free formulation that cures to a flexible, movement-tolerant foam
- Formulated for hot and tropical climates, suiting Indian site conditions
- Backed by ZTV-ING (RISS) certification and a FEICA Environmental Product Declaration
Limitations & considerations
- Provides a temporary water stop only, permanent sealing needs a follow-up resin such as Sika Injection-201 CE or Injection-203
- Requires trained, experienced operators and proper injection pumps, not a general-purpose DIY product
- Pot life is only around 2 hours at +20 degrees C, so mixed material must be used promptly
- Application is limited to a +5 to +35 degrees C ambient and substrate window
- REACH mandatory training is required before professional or industrial use
- Reaction speed varies with water, substrate and mix temperature, so lab timings are a guide, not a guarantee
Selection & best practice
Set out the crack, drill and fit injection packers at a spacing suited to the crack width and water pressure, then flush the crack if debris is present. Where the substrate or ambient temperature is below +10 degrees C, pre-plan an Sika Injection-AC10 dose to keep the expansion start predictable. Empty Parts A and B into a clean vessel and mix slowly and thoroughly for at least 3 minutes at up to 250 rpm, or run single-component as the site dictates, then transfer to the pump and use within the roughly 2-hour pot life. Inject from the lowest packer upward, watching for foam to travel and the flow to stop, and keep the injection controlled rather than forcing pressure. Skin formation on the resin surface should be removed and never stirred back in. Once the leak is arrested, re-inject with the permanent resin to complete the seal, and clean all tools with the Sika Injection Cleaning System before the foam sets in the lines.
Specifications
| Product type | Two-part, water-reactive polyurethane injection resin (temporary waterstopping) |
| Mixing ratio | Part A : Part B = 1:1 by volume |
| Viscosity at +20 C | Part A ~140 mPa·s; Part B ~155 mPa·s |
| Density at +20 C | Part A ~1.0 kg/l; Part B ~1.25 kg/l |
| Free-foaming expansion | Up to ~40 times its volume |
| Expansion time (EN 1406, +20 C) | Starts ~15 s after water contact; ends ~67 s |
| Pot life | ~2 hours at +20 C |
| Application temperature | +5 C to +35 C (ambient and substrate) |
| Packaging / shelf life | Part A 10 or 20 kg, Part B 12.5 or 25 kg; 24 months from production |
Industry use cases
Metro & Tunnelling
Stops high-pressure groundwater ingress through segment joints and cracks during micro-tunnelling and shaft construction so lining work can continue dry.
Basements & Car Parks
Controls live leaks in below-grade walls, construction joints and slabs before a permanent injection seal is applied.
Water Retaining Structures
First-response leak stopping in tanks, reservoirs and treatment plants where water is actively pushing through cracks.
Piling & Retaining Walls
Seals weeping bored piles, sheet-pile interfaces and anchor heads where groundwater tracks through the structure.
Dams & Hydraulic Works
Arrests active seepage through cracks and cavities as an emergency measure ahead of long-term rehabilitation.
Frequently asked questions
Is Sika Injection-101 RC a permanent leak repair?
Can it be used in a crack that is actively leaking water?
What is the mixing ratio?
How fast does it react?
What pack sizes and shelf life does it come in?
Do we need special equipment or training to apply it?
How we position Sika Injection-101 RC
Within the Sika injection family, Injection-101 RC is the temporary leak-stopper: pair it with Sika Injection-AC10 accelerator for cold or fast-set conditions, and always follow it with a permanent resin such as Sika Injection-201 CE or Sika Injection-203 to lock in the seal. Where a project standardises on Fosroc, Space Arc also supplies the equivalent Nitofill polyurethane injection range. For crack repair in dry substrates, an epoxy injection resin is the correct tool instead. As an authorised distributor and applicator across Delhi NCR and Pan-India, Space Arc Engineering can specify the right combination of foam, accelerator, permanent resin and packers for your leak.
Fosroc Nitofill PU1F — Choose the Fosroc single-component route when a specifier wants a truly one-part, catalyst-free foaming resin standardised on the Nitofill system for active leak sealing.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.