Fosroc Nitobond EC
A fast-curing, chemically resistant epoxy-resin bonding agent that locks new concrete, mortar and screeds to existing substrates for durable structural repairs.
What is it?
Nitobond EC is a Fosroc epoxy-resin bonding agent formulated with special fine fillers, used to create a high-strength adhesive bond between freshly placed cementitious materials and existing hardened concrete substrates.
Where is it used?
On concrete repair and rehabilitation works such as bonded screeds and floor toppings, structural patch repairs, beam/column/slab restoration and overlay bonding across industrial, infrastructure and building projects in India.
Why use it?
It delivers excellent adhesion, fast cure and chemical resistance in a two-part, easy-to-use system, giving a positive bond line stronger than the parent concrete and reducing delamination risk at the repair interface.
How is it applied?
The pre-weighed base and hardener are blended to a uniform colour, then brushed or roller-applied as a thin, continuous film onto a clean, sound substrate; the fresh repair mortar or concrete is placed while the coat is still tacky (wet-on-wet).
About Fosroc Nitobond EC
Fosroc Nitobond EC is part of the long-established Nitobond family of bonding agents that Indian contractors have relied on for decades to join new concrete and mortar to old. Where the SBR-latex grades in the range handle general-purpose, single-component bonding, Nitobond EC sits at the high-performance, structural end of the line: it is an epoxy-resin based product incorporating special fine fillers, supplied as a two-component (base plus hardener) system that cures to a tough, chemically resistant bond coat. The fillers improve body and trowel/brush behaviour so the film holds on vertical and overhead faces without sagging, while the epoxy chemistry develops an interface bond that is typically stronger than the surrounding concrete itself. For a repair or overlay, that interface is the single most common point of failure, which is precisely why a dedicated epoxy bonding agent is specified rather than a simple cement slurry or a wet-on-wet bonding bridge. In practice Nitobond EC is positioned for projects where the engineer wants the certainty of an epoxy bond line: structural concrete repairs, bonded toppings and screeds that must take traffic or plant loads, and rehabilitation of distressed slabs, beams and columns. It is solvent-free in character (consistent with the wider Nitobond EP-type epoxy bonding agents Fosroc markets), which makes it more comfortable to use in enclosed and occupied spaces than solvented adhesives. Because it is a manufactured, factory pre-weighed system, the site team mixes the whole base into the whole hardener, removing the guesswork and on-site error that dogs job-mixed adhesives. Space Arc Engineering supplies Nitobond EC as an authorised Fosroc distributor and applicator across Delhi NCR and Pan-India, and can pair it with the correct repair mortar, micro-concrete or screed from the Fosroc Renderoc, Patchroc and Conbextra systems so the whole repair build-up is compatible and warranty-clean. As regional formulations and pack sizes vary, we recommend confirming the current country-specific Technical Data Sheet and Safety Data Sheet for your project before specification.
The technical insight
The performance logic of an epoxy bonding agent like Nitobond EC comes down to two things: interfacial adhesion and the “open” (overlay) window. Epoxy resins wet out and chemically grip both the aged concrete and the fresh cementitious overlay, producing a bond that in epoxy bonding agents of this type routinely exceeds the tensile capacity of the parent concrete, so a pull-off test fails in the substrate rather than at the glue line. The fine mineral fillers do real work here: they thicken the film for non-sag application, extend coverage, and reduce resin-rich brittleness at the interface. The make-or-break site variable is timing. The fresh concrete or mortar must be placed while the bonding coat is still tacky and within the product’s overlay time; if the film is allowed to cure hard before overlaying, it stops behaving as a bonding bridge and becomes a debonding plane. Overlay time is strongly temperature-dependent for epoxies of this class, shortening sharply as ambient temperature rises, which is a critical planning factor for Indian summer site conditions, where work must be staged so that no more bonding agent is applied than can be over-coated in time. Surface preparation is the other non-negotiable: the substrate must be mechanically sound, free of laitance, dust, oil and curing-compound residue, and the bond strength of the whole system is ultimately limited by the tensile strength of that prepared surface, not by the epoxy. Solvent-free epoxy chemistry also means negligible shrinkage and good resistance to the alkaline, chloride and chemical exposure typical of industrial floors and infrastructure, which is why it is favoured where an SBR latex bond would be considered insufficiently robust.
Where it is used
- Bonding new concrete, mortar and screeds to existing hardened concrete in structural repair work
- Bonded floor toppings and granolithic / screed overlays subject to traffic or plant loading
- Patch repair and reinstatement of distressed slabs, beams, columns and soffits
- Rehabilitation of spalled or delaminated concrete where a high-strength epoxy bond line is specified
- Bonding of repair mortars and micro-concretes onto prepared substrates in industrial and infrastructure projects
- As an epoxy bonding bridge ahead of placing Fosroc Renderoc, Patchroc or Conbextra repair systems
Key advantages
- Epoxy-resin chemistry develops an interface bond typically stronger than the parent concrete, minimising delamination at the repair line
- Fast cure helps return repaired areas to service quickly compared with slower bonding systems
- Good chemical resistance suits industrial floors and aggressive exposure conditions
- Two-part, factory pre-weighed packs remove on-site mixing-ratio error
- Special fine fillers give body for non-sag application on vertical and overhead surfaces and extend coverage
- Solvent-free character makes it suitable for enclosed and occupied areas
- Easy brush or roller application with no specialist equipment
- Backed by Fosroc’s established Nitobond track record and locally available technical support
Limitations & considerations
- It is a bonding bridge, not a structural adhesive or repair mortar in itself, and must be over-coated within its overlay time while still tacky
- Overlay/open time shortens significantly as temperature rises, demanding careful staging in hot Indian site conditions
- Performance is capped by substrate preparation; bond fails in the concrete if the surface is weak, dusty or contaminated by laitance, oil or curing compound
- Two-part epoxy requires thorough full-pack mixing; part-mixing or incorrect proportioning compromises cure
- Higher material cost than SBR-latex or cement-slurry bonding alternatives, so it is reserved for higher-performance applications
- Not a moisture barrier or waterproofing membrane and should not be specified as one
- Regional formulation, exact pack sizes and published figures vary by country, so the current local TDS must be confirmed before use
Selection & best practice
Mechanically prepare the substrate to expose sound aggregate and remove all laitance, dust, oil and curing compound, then ensure it is clean and (for epoxy bonding) dry as required by the TDS. Mix the entire base into the entire hardener and blend to a uniform, streak-free colour. Apply a thin, continuous film by stiff brush or roller, working it well into the prepared surface, and never lay down more area than can be overlaid within the product’s overlay time at the prevailing temperature. Place the fresh repair mortar, concrete or screed while the bonding coat is still tacky (wet-on-wet); if the film has cured, abrade and re-coat. In hot weather, schedule work for cooler parts of the day and reduce the area coated per batch. Always verify the current country-specific Fosroc Technical Data Sheet for overlay times, coverage and surface-condition requirements before starting.
Specifications
| Product type | Epoxy-resin based bonding agent with special fine fillers |
| Composition | Two-component system (base + hardener), mixed on site |
| Primary function | Bonding fresh cementitious materials (concrete, mortar, screed) to existing hardened concrete |
| Key attributes (per Fosroc) | Excellent adhesion, fast cure, chemical resistance, easy to use |
| Bond performance | Interface bond typically exceeds the tensile strength of the parent concrete (failure occurs in the substrate) |
| Application method | Stiff brush or roller, applied as a thin continuous film |
| Overlay window | Cementitious overlay must be placed while the coat is still tacky; overlay time reduces as temperature rises |
| Solvent content | Solvent-free epoxy character (suited to enclosed / occupied areas) |
| Substrate requirement | Sound, clean concrete free of laitance, dust, oil and curing compound |
| Coverage | Confirm per current country-specific TDS (epoxy bonding agents in this class are typically around 3.5-4.0 m2/litre depending on substrate texture) |
| Pack sizes | Supplied in pre-weighed base + hardener packs; sizes vary by region (confirm with Fosroc / Space Arc) |
| Related Fosroc systems | Renderoc, Patchroc, Conbextra repair mortars and micro-concretes; Nitobond SBR / Nitobond EP within the same range |
Industry use cases
Industrial flooring & warehouses
Bonding new wear-resistant screeds and granolithic toppings to existing factory slabs that carry forklift and plant loads, where an epoxy bond line resists delamination under traffic and chemical spillage.
Bridges & infrastructure
Reinstating spalled or delaminated concrete on decks, piers and beams by bonding repair mortar or micro-concrete to the prepared substrate for a durable, monolithic repair.
Commercial & residential RCC repair
Patch-repairing distressed slabs, beams and columns in buildings, ensuring the new mortar grips the old concrete rather than peeling at the interface.
Water-retaining & treatment structures
Bonding repair concrete to tanks, channels and sumps where chemical resistance of the bond coat is valued, used in conjunction with the appropriate Fosroc repair and protection systems.
Precast & manufacturing plants
Joining fresh cementitious sections or toppings to cured precast elements where a fast-curing, high-strength bond shortens turnaround between casting and service.
Frequently asked questions
Is Fosroc Nitobond EC an epoxy or an SBR bonding agent?
What is Nitobond EC used for?
How is Nitobond EC applied?
How does Nitobond EC differ from Nitobond EP and Nitobond SBR?
Does the overlay timing really matter?
Where can I buy Fosroc Nitobond EC in Delhi NCR or Pan-India?
How we position Fosroc Nitobond EC
Within the Fosroc range, Nitobond EC is the epoxy-based, structural-grade member of the Nitobond bonding-agent family. It is closely related to Nitobond EP (the widely documented two-component, solvent-free epoxy bonding agent) and sits a clear tier above the single-component SBR-latex grades such as Nitobond SBR and Nitobond SBR Latex, which remain the economical choice for general bonding, gauging and waterproof screeds. On a typical repair, Nitobond EC is specified as the bond coat beneath Fosroc repair systems such as the Renderoc hand-placed and spray mortars, Patchroc fast-setting repair mortar, and Conbextra micro-concrete and grouts, giving a fully compatible, single-source build-up. Among competitor products an Indian specifier would credibly consider, the closest epoxy bonding alternatives are Sika’s Sikadur-32 / SikaTop Armatec-type epoxy bonding agents and STP (Standard Pidilite / STP Ltd) epoxy bonding systems, while for the lower-cost SBR-latex route the common alternatives are Dr. Fixit Pidicrete URP, MYK Laticrete / MBS-type latex bonding aids, and Sika Latex. The honest positioning is this: choose Nitobond EC (or an equivalent epoxy bonding agent) when the engineer needs a high-strength, chemically resistant, fast-curing structural bond line and is willing to manage epoxy timing and cost; choose an SBR-latex bonding aid when the application is general-purpose and budget-sensitive. Space Arc Engineering supplies and applies the genuine Fosroc product and will confirm the current country-specific TDS, pack sizes and the right grade for your exposure before you specify.
Related Concrete Repair products
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