Fosroc Nitofill AC 32F
Ultra-low-viscosity acrylic polymer gel injection resin for waterproofing leak-sealing, curtain injection, construction-joint treatment and soil stabilisation.
What is it?
A multi-component acrylic polymer gel injection resin from Fosroc’s Nitofill range that mixes with an accelerator and catalyst (diluted with water) to form a flexible, waterproof gel inside cracks, joints and the soil/structure interface. It is an injection material, not a gun-grade tooled joint sealant or a pre-formed waterstop.
Where is it used?
Below-grade and water-retaining structures: basement and lift-pit walls, car parks, tunnels, shafts, retaining walls, water tanks, road underpasses and construction/cold joints where water is leaking through cracks, honeycombs or behind membranes.
Why use it?
Its ultra-low viscosity lets it penetrate hairline cracks and damp substrates that paste sealants and rigid resins cannot, and its controllable gel time lets applicators stop active water ingress even in saline or mineral-laden ground water.
How is it applied?
Pumped through a single- or twin-line injection pump via packers, ports, re-injectable hoses or curtain-injection lances. The resin and accelerator/catalyst streams meet at the point of injection and gel within a site-tuned time window to seal the void.
About Fosroc Nitofill AC 32F
Fosroc Nitofill AC 32F is an acrylic polymer based gel injection resin within the established Nitofill family of injection grouts. Unlike a tooled joint sealant that is gunned into a prepared joint, AC 32F is a pumpable, water-thin resin engineered to be injected into cracks, voids, construction joints and the gap behind waterproofing membranes, where it reacts to form a flexible, water-resistant gel. The product is a multi-component system: a blend of acrylic polymers used together with an accelerator and a catalyst, with the mix diluted in water. When the streams combine, a controlled chemical reaction produces a gel rather than a hard solid, which is what allows it to remain flexible and to follow subsequent minor movement in the structure.
The defining characteristic of Nitofill AC 32F is its extremely low viscosity, close to that of water. This is precisely what makes it suited to stopping water ingress: it can travel into hairline cracks, fine honeycombing and saturated ground that thicker polyurethane or epoxy injection resins struggle to reach. Because the gel time is governed by the accelerator dosage, the applicator can dial the set from a few seconds to several minutes to match crack width, water pressure and ambient temperature on site. The resin will also react in the presence of mineral salts and saline water, a common condition in coastal and high-water-table sites across India, where many waterborne systems are compromised.
It is important to position this product accurately. Despite sitting under the broad “joint sealants and joint treatment” heading because it treats leaking joints and cracks, Nitofill AC 32F is not an elastomeric gun-grade sealant such as Fosroc Nitoseal, and it is not a PVC or hydrophilic strip waterstop. There is therefore no movement accommodation factor, ISO 11600 class or ASTM C920 rating associated with it, and it is not gunned into a backer-rod-supported joint. It is a specialist remedial and waterproofing injection material applied by trained injection crews.
The technical insight
The functional logic of Nitofill AC 32F is hydrogel chemistry rather than adhesive bridging. Acrylic (acrylate-type) injection resins are supplied so water-thin that they behave almost like the water they are meant to displace, which is the whole point: to seal a leaking crack you must first get the resin to the full depth of the leak path, including damp and flowing zones that reject pastes and high-viscosity resins. Once injected, the accelerator/catalyst system triggers polymerisation into a soft, rubbery gel that swells and keys into the substrate and into any soil grains at the structure interface, blocking the water path while staying flexible enough to tolerate small subsequent movement. Because gel time is controlled by accelerator dosing, a crew faced with high-pressure flowing water can shorten the set so the resin gels before it washes out, then lengthen it for slow-weep cracks where deeper travel is wanted. This separates acrylic gels from one-part PU foam resins (e.g. Nitofill PU 1F), which expand on contact with water to form a temporary foam dam, and from rigid epoxy crack-injection resins (Nitofill LV / EPLV) that structurally re-bond dormant cracks but cannot be injected into actively wet, moving cracks. Selecting between these is the core technical decision: structural re-bonding of dry cracks calls for epoxy; emergency water cut-off calls for PU foam; durable, flexible, deep curtain and joint sealing in saturated or saline ground is where acrylic gels such as AC 32F are specified.
Where it is used
- Stopping active water leaks through cracks and honeycombing in basement, lift-pit and retaining walls
- Curtain (veil) injection between the structure and surrounding soil to form a continuous waterproof barrier
- Sealing leaking construction and cold joints in water-retaining and below-grade concrete
- Tunnel and shaft lining works, including segment gaskets, cracks and SCL/VSM linings
- Re-injectable hose and PVC compartmentalised membrane systems built into new construction joints
- Soil and ground stabilisation / consolidation at the structure perimeter
- Primary and secondary injection in car parks, road underpasses and underground service structures
- Flexible sealing of fine cracks where a rigid epoxy would later re-crack under movement
Key advantages
- Ultra-low viscosity penetrates hairline cracks, fine voids and damp or flowing substrates
- Cures to a flexible gel that tolerates minor ongoing movement rather than a brittle solid
- Gel/set time is adjustable on site through accelerator dosing to suit water flow and temperature
- Reacts and seals even in the presence of mineral salts and saline ground water
- Effective for curtain injection and soil-side sealing, not just in-crack filling
- Good chemical resistance suits aggressive below-grade and ground-water environments
- Compatible with re-injectable hose and compartmentalised membrane detailing for designed-in serviceability
- Backed by Fosroc technical support and locally available through Space Arc Engineering in Delhi NCR and Pan-India
Limitations & considerations
- Not a tooled gun-grade joint sealant and not a strip/PVC waterstop, so it has no movement accommodation factor, ISO 11600 class or ASTM C920 rating
- Requires specialised injection pumps, packers/ports and trained applicators; it is not a hand-applied product
- Forms a flexible gel, not a load-transferring structural bond, so it does not restore structural continuity to cracked concrete the way an epoxy does
- Performance depends heavily on correct accelerator dosing and injection technique for the specific water condition
- As a multi-component water-diluted system, it needs accurate on-site metering and clean equipment to avoid premature gelling
- Published official numeric data (viscosity, gel-time figures, density, pack sizes) is limited on the public datasheet; always confirm current values against the project-specific Fosroc TDS and MSDS
- Not intended for exposed movement joints in facades, floors or glazing, where an elastomeric Nitoseal sealant is the correct product
Selection & best practice
Treat Nitofill AC 32F as an engineered injection operation, not a fill-and-forget product. First diagnose the leak: map crack widths, water pressure and whether flow is active, then choose the system (acrylic gel for flexible, saturated/saline conditions; reserve epoxy for dry structural cracks and PU foam for emergency cut-off). Drill and set mechanical packers or ports at an angle that intersects the crack at depth, typically staggered either side of the crack, with spacing reduced for finer cracks and higher water heads. Flush the crack with water before injection to confirm the path and to pre-wet the substrate. Calibrate the pump and, critically, trial the accelerator dosage to fix a gel time that lets the resin reach full depth yet sets before it is washed away, shortening the set for high-pressure flowing leaks and lengthening it for slow weeps. Inject from the lowest point upward (or follow the designed sequence for curtain and hose systems), watching for resin showing at adjacent ports to confirm travel. For designed-in serviceability, integrate re-injectable hoses or compartmentalised membranes at construction joints during new build so AC 32F can be re-injected later if a joint weeps. Always work to the current project-specific Fosroc technical data sheet and MSDS, use the specified PPE, keep resin and catalyst lines clearly separated, and clean equipment immediately after use to prevent gelling inside the pump.
Specifications
| Product type | Acrylic polymer gel injection resin (Nitofill injection range) |
| Composition | Multi-component system: acrylic polymer resin + accelerator + catalyst, diluted with water |
| Cure mechanism | Chemical reaction on mixing forms a flexible, waterproof gel |
| Viscosity | Ultra-low (water-thin) for deep penetration of fine cracks and damp substrates |
| Gel / set time | Adjustable on site via accelerator dosing to suit water flow and temperature |
| Flexibility | Cured gel is flexible, accommodating minor subsequent movement |
| Chemical / saline tolerance | Good chemical resistance; reacts even in mineral and saline (wet) conditions |
| Primary uses | Leak sealing, curtain injection, construction/cold joints, tunnel & shaft lining, soil stabilisation |
| Application method | Pumped injection via packers/ports, re-injectable hoses or curtain lances |
| Application category | Specialist remedial / waterproofing injection (trained applicators) |
| Movement accommodation / sealant class | Not applicable — this is an injection resin, not a gun-grade joint sealant or waterstop |
| Pack size | Component pack — confirm current pack configuration against the project-specific Fosroc TDS / Space Arc |
Industry use cases
Basements & deep substructures
Stopping water ingress through cracks, cold joints and honeycombing in basement and lift-pit walls of commercial and residential towers across Delhi NCR, including curtain injection on the soil side where excavation access is gone.
Metro, tunnels & infrastructure
Sealing segment-gasket leaks, lining cracks and shaft walls in metro and road tunnels and underpasses, where flexible, saline-tolerant gels are needed for permanently wet ground conditions.
Water-retaining & treatment structures
Remedial sealing of leaking construction joints and cracks in water tanks, STP/ETP and reservoir walls where a flexible, water-reactive seal is preferred over a rigid one.
Car parks & podiums
Primary and secondary injection to arrest seepage through deck joints and slab cracks in multi-level and podium car parks.
New-build designed-in waterproofing
Charging re-injectable hose systems and PVC compartmentalised membranes cast into construction joints, so joints can be sealed or re-sealed by injection over the structure’s life.
Ground & perimeter stabilisation
Consolidating and waterproofing the soil-to-structure interface around basements and shafts to cut off water paths before they reach the concrete.
Frequently asked questions
Is Nitofill AC 32F a joint sealant like Nitoseal?
What type of chemistry is it and how does it cure?
Can it seal cracks that are actively leaking water?
How is it different from Nitofill LV, EPLV or PU 1F?
Does it have a movement accommodation factor or ISO 11600 / ASTM C920 rating?
Who should apply it, and can Space Arc supply it in India?
How we position Fosroc Nitofill AC 32F
Within Fosroc’s portfolio, Nitofill AC 32F sits at the flexible, waterproofing end of the Nitofill injection family. It complements rather than competes with the rigid epoxy crack-injection resins Nitofill LV and Nitofill EPLV (for structural re-bonding of dry cracks) and the polyurethane injection resins such as Nitofill PU 1F and the WS-series (for water-reactive foam cut-off), while its closest sibling in chemistry and intent is Fosroc’s methacrylate gel injection system Supercast Acrylate 200. For exposed tooled movement and construction joints — a genuinely different job — the correct Fosroc products are the Nitoseal elastomeric sealants (Nitoseal MS, PU and polysulphide grades) and Thioflex/Colpor for trafficked and pavement joints, none of which overlap with this injection resin. Among credible alternatives an Indian consultant or contractor may evaluate, acrylic and PU gel injection resins from Sika (e.g. the Sika InjectoCem / Sikadur-Injection and SikaFix gel ranges), MBCC/Master Builders Solutions (MasterInject and MasterSeal injection systems) and STP/Pidilite are comparable for leak-sealing and curtain injection; for surface joint sealants the comparison set is Sikaflex, MasterSeal NP/AP and STP sealants. The honest summary: specify Nitofill AC 32F when the problem is stopping water through cracks, joints, membranes or soil in wet, saline or movement-prone conditions — and reach for a Nitoseal sealant, an epoxy injection resin or a PU foam resin when the job is, respectively, a tooled movement joint, a dry structural crack, or an emergency flow cut-off.
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