Fosroc Nitobond EP Std
Solvent-free, two-component epoxy resin bonding agent for structural-grade adhesion between old and new concrete, with a long open life for steel-fixing and formwork.
What is it?
A two-component, solvent-free epoxy resin bonding agent supplied in pre-weighed base (white) and hardener (green) tins for site mixing. It bonds fresh, wet cementitious materials to existing concrete and complies with ASTM C881 Type II, grade 2, class E & F.
Where is it used?
Bridge decks, road and pavement repairs, loading bays, industrial floors, granolithic and bonded floor toppings, and structural repair zones where old concrete meets new concrete, screed or mortar – both internal and external.
Why use it?
It develops positive adhesion that exceeds the tensile strength of the host concrete, while its slow cure gives a long open window to erect reinforcement and formwork. Being solvent-free, it is safe to use in enclosed and confined locations.
How is it applied?
Surfaces are mechanically prepared and decontaminated, the two components are power-mixed for around four minutes to a uniform colour, then brush- or roller-applied as an unbroken film. Fresh concrete or screed is placed while the coat is still tacky, within the stated overlay time.
About Fosroc Nitobond EP Std
Fosroc Nitobond EP Std is the standard-grade member of the Nitobond EP family of epoxy bonding agents, formulated to create a durable, structural bond between freshly placed cementitious materials and an existing hardened concrete substrate. It is supplied as a two-component, solvent-free epoxy resin system in pre-weighed quantities, so there is no batching guesswork on site: the entire hardener tin is emptied into the base tin and mixed. A deliberate colour contrast – a white base and a green hardener – acts as a built-in quality check, because the operator can see at a glance, from the uniform colour, that mixing is complete. For Indian contractors, consultants and procurement teams, Nitobond EP Std sits in the bonding-agent slot of any concrete repair or new-to-old jointing specification, alongside cement-modified SBR latex options when full epoxy performance is not required. Its defining commercial feature is the long open or overlay life, which is precisely why the standard grade is specified on jobs where steel reinforcement has to be cut, fixed and tied, or formwork erected, after the bond coat is down but before the new pour. The product is non-flammable and water-based in handling terms only insofar as it tolerates damp substrates; the resin chemistry itself is solvent-free epoxy. Space Arc Engineering supplies Nitobond EP Std as an authorised Fosroc distributor and applicator across Delhi NCR and Pan-India, with technical guidance on substrate preparation, overlay timing and pack estimation for each project.
The technical insight
The performance logic of Nitobond EP Std rests on three linked properties. First, adhesion: the cured film develops a bond that exceeds the tensile strength of typical host concrete, so a correctly prepared and primed repair fails in the parent concrete rather than at the interface – the outcome a structural engineer wants. Second, mechanical strength: independent test data give a compressive strength of 70 N/mm2 (ASTM D695), a tensile strength of 30 N/mm2 (ASTM D638) and a slant shear strength of 36 N/mm2 (BS 6319 Part 4), placing it firmly in the structural-adhesive band rather than the cosmetic primer band. Third, and most operationally important, the cure profile is intentionally slow. The standard grade is engineered around an overlay window of up to 16 hours at 25C, 12 hours at 35C and 5 hours at 45C, with a working (pot) life of roughly 160 minutes at 25C falling to about 80 minutes at 35C for the 4-litre pack. This long latitude is what separates EP Std from quicker-setting bonding agents: it buys time on large or congested pours. The trade-off is that the new concrete or screed must be placed while the film is tacky – not wet, and never after it has gone hard. Once the coat cures past tack, it becomes a slip plane that defeats the bond entirely, so overlay timing is the single most critical control on site. Water absorption is very low at 0.05% (ASTM D570), and the system meets ASTM C881 Type II, grade 2, class E & F. A cold-weather variant, Nitobond EPFS, is available on request for low-temperature working below the 5C application floor.
Where it is used
- Bonding fresh concrete, screed or mortar to existing hardened concrete in repair and rehabilitation works
- Bridge deck repairs and overlays where new and old concrete must act monolithically
- Road, pavement and highway slab repairs and patch reinstatement
- Loading bays, ramps and heavy-duty industrial floors subject to traffic and impact
- Bonded and granolithic floor toppings over a structural base
- Repairs requiring a substrate or repair barrier where the substrate stays permanently damp or wet
- Structural repair sections where additional reinforcement and formwork must be fixed after priming
- Internal and external concrete jointing in enclosed or confined spaces, owing to the solvent-free chemistry
Key advantages
- Develops positive adhesion that exceeds the tensile strength of the host concrete
- Solvent-free epoxy, so it is non-flammable and safe to use in enclosed and confined locations
- Long open / overlay life allows reinforcement fixing and formwork erection after priming
- Can be applied to dry or damp substrates, widening the site weather and curing window
- Differential pigmentation (white base, green hardener) gives a visual confirmation of correct mixing
- High mechanical strength – 70 N/mm2 compressive, 30 N/mm2 tensile, 36 N/mm2 slant shear
- Very low water absorption of 0.05%, supporting durability in wet exposure
- Pre-weighed two-pack supply removes site batching errors
- Complies with ASTM C881 Type II, grade 2, class E & F for structural epoxy bonding
Limitations & considerations
- Overlay timing is critical – if the film cures past tack it becomes a slip plane and must be mechanically removed and re-applied
- Must not be applied when temperature is below 5C, or is 5C and falling; cold-weather jobs need the Nitobond EPFS variant
- Pot life shortens sharply with heat (about 160 min at 25C down to ~80 min at 35C), demanding tight batch planning in Indian summer conditions
- Hardened or cured material can only be removed mechanically; tools must be cleaned with Fosroc Solvent 102 immediately after use
- Higher unit cost than cement-modified SBR latex bonding agents, so it is over-specification for light or non-structural toppings
- Requires thorough mechanical surface preparation (scabbling or grit-blasting) and decontamination – a poorly prepared substrate undermines the bond
- Application above 35C needs prudent precautions: shaded storage, cool equipment and avoidance of midday or direct-sun placement
- Resins, hardeners and solvents can sensitise skin; PPE and ventilation are required
Selection & best practice
Prepare the substrate mechanically – scabble or grit-blast to remove laitance and expose aggregate, then degrease and verify soundness with a pull-off test. Have all reinforcement and formwork cut, shaped and ready before mixing starts. Stir base and hardener separately, then combine the full hardener tin into the base and power-mix with a slow-speed paddle for two minutes, scrape the sides, and mix two minutes more until the colour is fully uniform. Brush or roller the coat on as an unbroken film, then place the new concrete or screed while the bond coat is still tacky – never wet, never hard – keeping inside the overlay window (16 h at 25C, 12 h at 35C, 5 h at 45C). In hot weather above 35C, store packs cool and out of direct sun, keep equipment shaded, and avoid midday application. If the overlay time is missed, mechanically remove the cured film and re-prime. Clean tools with Fosroc Solvent 102 immediately after use.
Specifications
| Product type | Two-component, solvent-free epoxy resin bonding agent |
| Components | Base (white) + Hardener (green), pre-weighed for site mixing |
| Standards compliance | ASTM C881: Type II, grade 2, class E & F |
| Compressive strength | 70 N/mm2 (ASTM D695) |
| Tensile strength | 30 N/mm2 (ASTM D638) |
| Slant shear strength | 36 N/mm2 (BS 6319 Part 4) |
| Water absorption | 0.05% (ASTM D570) |
| Working / pot life (4 L pack) | 160 min @ 25C, 90 min @ 30C, 80 min @ 35C |
| Maximum overlay time | 16 h @ 25C, 12 h @ 35C, 5 h @ 45C |
| Minimum overlay time | Overlay when tacky but not wet |
| Full cure | 5 days @ 35C, 4 days @ 45C |
| Minimum application temperature | 5C (not falling); use Nitobond EPFS below this |
| Coverage | 3.5 – 4.0 m2/litre (theoretical; reduce for wastage and rough substrates) |
| Application method | Brush or roller, as an unbroken film |
| Pack sizes | 1 litre and 4 litre packs |
| Shelf life | 12 months in original unopened packs, stored dry |
| Fire / flammability | Non-flammable |
Industry use cases
Bridges & Highways
Bonding new overlay concrete to existing bridge decks and carriageway slabs so the repair acts monolithically with the parent structure under traffic and dynamic load.
Industrial Flooring
Priming structural bases before bonded or granolithic toppings in factories, warehouses and loading bays where the floor takes heavy point loads and wheeled traffic.
Concrete Repair & Rehabilitation
Acting as the interface coat in patch repairs and section enlargements, including barrier-type repairs where the substrate stays permanently damp or wet.
Water-Retaining & Wet Structures
Bonding new to old concrete in tanks, channels and damp environments, where the 0.05% water absorption and damp-substrate tolerance are advantageous.
Precast & Formwork-Based Pours
Used on vertical and soffit pours supported by formwork, where the long open life lets crews fix steel and erect shutters before the new concrete goes in.
Frequently asked questions
Is Fosroc Nitobond EP Std a structural bonding agent?
How long do I have to place the new concrete after applying it?
What is the difference between Nitobond EP Std and Nitobond SBR?
Can it be applied to a damp substrate?
What is the coverage and how is it supplied in India?
What is its pot life and shelf life?
How we position Fosroc Nitobond EP Std
Nitobond EP Std is the structural-grade epoxy bonding agent in Fosroc’s repair portfolio, chosen when the new-to-old concrete interface has to carry load or face aggressive exposure. It pairs naturally with Fosroc’s Renderoc range of repair mortars and the Nitomortar epoxy mortars on a typical patch-repair specification, and it sits a tier above Fosroc Nitobond SBR – the styrene-butadiene latex used for cement-gauged bonding slurries and modified mortars where full epoxy performance is not warranted. Against the broader Indian market, credible alternatives a specifier may evaluate include Sika’s epoxy bonding agents such as Sikadur-32, MBS (MYK) construction-chemical bonding agents, Dr. Fixit’s bond-aid and epoxy bonding products, and STP (Pidilite) systems. The honest distinction is one of fit, not blanket superiority: cement-modified SBR latexes are more economical and forgiving for light or non-structural toppings, whereas Nitobond EP Std earns its higher cost on structural repairs through its very long overlay window, its ability to bond to damp substrates and its certified ASTM C881 Type II performance. Where a project is already specified around the Fosroc system – Renderoc, Nitomortar, Nitobond – keeping the bonding agent within that family avoids compatibility risk. Space Arc Engineering, as an authorised Fosroc distributor and applicator, can advise on whether EP Std, EPFS for cold weather, or an SBR-based bonding coat is the right specification for a given job.
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