Fosroc Nitobond ACS
High-tack acrylic resin liquid bonding agent for keying renders, screeds and repair mortars to concrete and masonry — supplied and applied by Space Arc Engineering across Delhi NCR and Pan-India.
What is it?
A single-component, ready-to-use acrylic (acrylic resin) emulsion bonding agent that creates a high-tack adhesive film between old and new cementitious surfaces.
Where is it used?
Bonding fresh plaster, renders, screeds, repair mortars and toppings to existing concrete, masonry and brickwork on repair, refurbishment and new-build projects.
Why use it?
It delivers very high and long-lasting tack, so trades can apply the next layer within a generous open window without the bond film drying out and failing.
How is it applied?
Brush, roller or spray a thin, even film onto a clean, sound, pre-wetted substrate, then apply the cementitious overlay while the film is still tacky.
About Fosroc Nitobond ACS
Fosroc Nitobond ACS is an acrylic resin-based liquid bonding agent (also described by Fosroc as an acrylic-resin liquid adhesive) used to improve the adhesion of cement-based materials to existing substrates. It belongs to the well-established Fosroc Nitobond family of bonding agents, sitting alongside the SBR-latex, acrylic (AR), high-build acrylic (HAR), PVA and epoxy (EP) grades. Where many traditional bonding aids flash off quickly and demand that the topping be placed almost immediately, the defining characteristic of Nitobond ACS is its very high and long-lasting tack — the applied film stays “open” and grabby for an extended period, which is a practical advantage on Indian sites where labour sequencing, large wall areas and summer heat often delay the placement of the next coat. In essence, it is a brush- or spray-applied liquid that dries to a tacky, contact-adhesive-like film, into which fresh mortar, plaster, render or screed is worked to form a mechanical and chemical key. For contractors, consultants and architects specifying repair and refurbishment work in Delhi NCR and across India, Nitobond ACS offers a simple, water-based, low-odour way to reduce the risk of debonding, hollowing and delamination at the interface between old and new concrete — one of the most common and avoidable failure points in plastering and patch-repair work.
The technical insight
The reason an acrylic bonding agent like Nitobond ACS works is that ordinary new-to-old cementitious interfaces are weak: the existing concrete is dense, low in suction and often contaminated, so fresh mortar has little to grip and tends to shrink away as it cures. An acrylic emulsion film bridges this gap two ways — it provides a high-tack, polymer-rich contact layer that physically holds the fresh mix, and as the cement hydrates the acrylic co-films and intermingles with the cement matrix to densify the interfacial zone and reduce micro-cracking. The “long-lasting tack” claim is technically meaningful: acrylic emulsions can be formulated to remain pressure-sensitive after the water carrier has evaporated, so the film behaves like a contact adhesive rather than a primer that must be over-coated wet. This widens the application window and forgives the start-stop reality of site work. Because the binder is acrylic rather than SBR or epoxy, the film also offers good resistance to ageing, UV and yellowing and remains paintable/over-plasterable, while staying water-based, single-component and non-flammable. The trade-off is that, like all polymer-emulsion bonding agents, the cured film is not intended for permanent water immersion or high structural shear duty — for those, an epoxy bonding agent (Nitobond EP) is the correct choice.
Where it is used
- Bonding fresh internal and external cement plaster/render to existing concrete columns, beams, slabs and shear walls
- Keying cementitious repair mortars and patch repairs to prepared concrete in refurbishment and rehabilitation work
- Improving adhesion of floor screeds and toppings to existing concrete bases
- Bonding new concrete and mortar to old (cold-joint preparation) on repair and extension works
- Treating dense, low-suction or smooth substrates such as RCC and dense blockwork before plastering to prevent hollowing
- Bridging dissimilar or difficult surfaces where standard cement-only bonding is unreliable
Key advantages
- Very high and long-lasting tack gives a wide open time, so the topping can be placed without rushing
- Single-component and ready to use — no mixing of resins or hardeners required, reducing on-site error
- Water-based, low-odour and non-flammable, suitable for occupied and enclosed interiors
- Acrylic binder resists ageing and yellowing and remains paintable/over-plasterable
- Economical coverage of 2.0–3.0 m²/kg keeps the per-square-metre cost low on large areas
- Reduces the risk of debonding, hollowing and delamination at new-to-old interfaces
- Easy brush, roller or spray application with simple water clean-up of tools while wet
- Backed by Fosroc’s pan-India technical support and Space Arc’s local stock and applicator team
Limitations & considerations
- As a polymer-emulsion bonding agent it is not a substitute for an epoxy bonding agent (Nitobond EP) where high structural shear bond or permanent water immersion is required
- Performance depends entirely on substrate preparation — bond will fail over loose, friable, oily, dusty or laitance-covered surfaces
- Not formulated as a structural adhesive or a standalone waterproofing product
- Like most acrylic emulsions, it should be protected from frost in storage and from rain immediately after application until the cementitious layer has set
- Coverage of 2.0–3.0 m²/kg varies with substrate porosity and texture, so rough or absorbent surfaces will consume more material
- Always confirm the current Fosroc Technical Data Sheet and method statement for the specific grade, batch and region before specifying, as formulations and figures can be updated
Selection & best practice
Mechanically prepare the substrate to remove all laitance, dust, oil, curing compounds and loose material, and expose a sound, slightly roughened surface. Pre-wet absorbent substrates and bring them to a saturated surface-dry (SSD) condition without standing water. Stir the Nitobond ACS and apply a single thin, even film by brush, roller or spray, working it well into the surface. Because the product is valued for its long-lasting tack, place the fresh plaster, render, screed or repair mortar onto the still-tacky film — do not let the film be over-coated with dust or contaminated before the topping goes on. Apply the cementitious layer firmly to achieve full contact, then cure the new mortar properly (moist curing) as you would any cement work. Protect freshly applied work from rain and direct sun until set. For demanding structural or constantly wet locations, switch to an epoxy bonding agent and consult Space Arc’s technical team for a project-specific method statement.
Specifications
| Product type | Acrylic resin-based liquid bonding agent / adhesive (single-component, ready to use) |
| Base chemistry | Acrylic resin emulsion (water-based) |
| Key property | Very high and long-lasting tack |
| Coverage | 2.0–3.0 m²/kg (varies with substrate porosity and texture) |
| Application method | Brush, roller or spray as a thin even film |
| Substrates | Concrete, masonry, brickwork and other sound cementitious surfaces |
| Typical uses | Bonding plaster, render, screed, repair mortar and new concrete to existing surfaces |
| Pack / container sizes | 5 kg, 25 kg, 200 kg and 1000 kg containers |
| Tool cleaning | Clean tools with water while the product is still wet |
| Brand / range | Fosroc Nitobond bonding-agent range |
Industry use cases
Building repair & refurbishment
Keying cementitious patch repairs and re-plastering onto prepared RCC columns, beams and slabs in ageing residential and commercial buildings across Delhi NCR.
New-build plastering
Treating dense, low-suction RCC and dense blockwork before internal and external plaster to prevent the hollowing and debonding that commonly trigger callbacks.
Flooring & screeds
Improving the adhesion of cement screeds and toppings to existing concrete bases during fit-outs and floor renovations.
Infrastructure & civil rehabilitation
Preparing cold joints and bonding new mortar to old concrete in repair, strengthening and extension works where a fast epoxy bond is not required.
Industrial & institutional maintenance
Bonding render and repair mortar to plant-room walls, boundary structures and warehouse elements during planned maintenance, with low odour suiting occupied premises.
Frequently asked questions
What exactly is Fosroc Nitobond ACS?
How is Nitobond ACS different from Nitobond SBR or Nitobond EP?
What coverage and pack sizes should I plan for?
Do I still need to prepare and wet the surface?
Can Nitobond ACS be used for waterproofing or under permanent water?
Where can I buy genuine Fosroc Nitobond ACS in India?
How we position Fosroc Nitobond ACS
Within the Fosroc Nitobond range, Nitobond ACS occupies the high-tack acrylic niche for general-purpose plaster, render, screed and repair-mortar bonding — distinct from the multi-purpose SBR-latex grade Nitobond SBR (which doubles as a mortar additive), the acrylic Nitobond AR and high-build Nitobond HAR, the economical Nitobond PVA, and the structural two-part epoxy Nitobond EP that should be specified wherever high shear bond or wet-condition durability is needed. Pair it with Fosroc’s Renderoc and Patchroc repair mortars or Nitotile/Nitobond tile adhesives within a single specification for a coherent system. Among competing brands available in India, credible alternatives in the bonding-agent space include Sika’s SBR and acrylic latex bonding agents (e.g. SikaLatex / Sika Latex Power and SikaTop Armatec ranges), MBS (MYK Schomburg) bonding additives, Dr. Fixit Pidicrete URP/SBR-based bonding aids, and STP (Sika-STP) latex products. For Indian contractors, consultants and procurement teams, the practical case for Nitobond ACS is its long-lasting tack, simple single-component use and low per-square-metre cost backed by Fosroc’s brand assurance — while Space Arc Engineering adds authorised distribution, local stock and on-site applicator support across Delhi NCR and Pan-India. Specifiers should always validate the current Fosroc Technical Data Sheet for the exact grade and region, as polymer bonding-agent formulations and figures are periodically updated.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.