Fosroc Nitocote ET83
A two-pack coal tar epoxy protective coating for bridge-deck waterproofing and long-term corrosion protection of concrete and steel in aggressive, immersed and buried environments.
What is it?
Nitocote ET83 is a Fosroc tar-epoxy (coal-tar-modified epoxy) protective and waterproofing coating, supplied as a two-component system that cures to a tough, low-permeability film.
Where is it used?
Waterproofing of bridge decks and large concrete surfaces, plus corrosion protection of concrete, iron and steel in water/effluent treatment plants, tanks, swimming pools, underground walls and other civil-engineering structures.
Why use it?
It combines good chemical resistance, abrasion resistance and very low water absorption in an economical high-build coating, giving durable barrier protection where structures are exposed to moisture, effluent or aggressive ground conditions.
How is it applied?
Mix the two pre-weighed packs thoroughly, then apply by brush, roller or airless spray to a clean, sound, prepared substrate, typically as a multi-coat system at a controlled wet/dry film thickness (indicative dosage around 1.0 kg/m2).
About Fosroc Nitocote ET83
Fosroc Nitocote ET83 is a protective and waterproofing coating built on a coal-tar-modified epoxy (“tar epoxy”) binder. It is supplied as a two-pack material — a base and a hardener in pre-weighed quantities — that are blended on site and applied to form a continuous, chemically resistant membrane over concrete and steel. According to Fosroc’s product information, ET83 is positioned both as a waterproofing layer for bridge decks and large surfaces (with an indicative dosage in the order of 1.0 kg/m2) and as an anti-corrosive barrier for iron, steel and concrete exposed to water, effluent and buried conditions. In the wider Fosroc Nitocote ET range (ET402, ET402E, ET550, etc.), the same coal-tar-epoxy chemistry is used as a high-build coating applied in two coats; ET83 belongs to this established family of bridge and immersion-grade coatings. For Indian projects, Space Arc Engineering supplies ET83 as part of the Fosroc protective-coatings portfolio and recommends confirming the current country-specific Technical Data Sheet (TDS) before specification, because pack configuration, exact film build and approved primers can vary by region. The coating is intended for contractors and applicators who need a robust, cost-effective barrier on infrastructure assets — road and rail bridges, water and wastewater structures, tank linings and underground RCC — where the combination of moisture, abrasion and mild chemical attack would otherwise shorten service life. Used correctly over a properly prepared substrate, ET83 helps protect the embedded reinforcement and the concrete matrix from the chloride- and sulphate-laden water that drives corrosion and deterioration in Indian climatic and ground conditions.
The technical insight
The performance of a coal-tar epoxy like Nitocote ET83 comes from the marriage of two chemistries. The epoxy resin provides adhesion, hardness, abrasion resistance and chemical resistance, while the coal-tar pitch contributes hydrophobicity, flexibility and a dense, low-permeability film at lower cost than a pure epoxy. The result is a coating with very low water absorption — the key property for bridge-deck waterproofing and immersed/buried service — combined with resistance to the dilute acids, alkalis, salts and effluent typical of water and wastewater plants. Because it is a reactive two-pack system, ET83 cures by chemical cross-linking rather than solvent evaporation, so correct mix ratio, thorough mixing and respecting the pot life and overcoat window are non-negotiable for achieving the rated film. The dark/black colour is inherent to the coal-tar component and should be expected. Film build (dry film thickness, DFT) is the single most important specification variable: barrier protection scales with achieving the specified DFT across the whole surface, including pinholes, edges and rebates, which is why two or more coats are normally specified and wet-film-thickness checks during application are good practice. As with all reactive coatings, performance is sensitive to substrate moisture, surface temperature and dew point at the time of application.
Where it is used
- Waterproofing of concrete and steel bridge decks and large horizontal surfaces
- Corrosion protection of iron and steel structures (gates, pipework, embedded steel)
- Protective lining for water treatment and effluent/sewage treatment plant structures
- Internal protection of tanks, sumps and swimming-pool structures
- Tanking and protection of buried/underground RCC walls and retaining structures
- Barrier coating for concrete exposed to moisture, mild chemical attack and abrasion
Key advantages
- Good resistance to a range of chemicals, dilute acids, alkalis, salts and effluent
- Abrasion-resistant film suited to trafficked and immersed surfaces
- Very low water absorption — effective barrier for waterproofing and immersion
- Two-pack, pre-weighed packs reduce on-site mixing errors
- Economical high-build coating compared with pure-epoxy alternatives
- Bonds to both concrete and steel, allowing a single product across mixed substrates
- Backed by Fosroc’s established Nitocote ET coal-tar-epoxy track record on infrastructure
Limitations & considerations
- Coal-tar-based and inherently dark/black — not suitable where light or decorative finishes are required
- Reactive system with a limited pot life; mixed material must be used within the working time
- Requires thorough surface preparation (clean, sound, dry, profiled) for adhesion and full DFT
- Sensitive to substrate moisture, low temperature and high humidity/dew point during cure
- Solvent/coal-tar content demands proper ventilation and PPE during application
- Coal-tar coatings face tightening regulatory and worker-exposure scrutiny in some markets — confirm current acceptability and use the latest SDS
- Exact coverage, DFT, primer and pack data must be verified against the current country-specific Fosroc TDS before specification
Selection & best practice
Always start from the current country-specific Fosroc TDS and SDS for the exact mix ratio, DFT, primer and pot life, as these govern the warranty. Prepare the substrate so it is clean, sound, dry and free of laitance, oil and loose material — grit-blasting or mechanical preparation for steel and concrete gives the best key. Make good honeycombing, blowholes and cracks with the appropriate Fosroc Renderoc/Nitomortar repair products and apply the recommended Nitoprime primer where specified. Mix the full base and hardener packs together (never split-mix part packs) for the stated time, and apply within the pot life by brush, roller or airless spray, building the specified number of coats to reach the rated DFT; check wet film thickness as you go and respect minimum/maximum overcoat intervals. Avoid application below the recommended temperature, onto damp surfaces, or when condensation/dew point risk is high, and ensure adequate ventilation and PPE throughout. Allow full cure before immersion or commissioning.
Specifications
| Product type | Two-pack coal-tar-modified epoxy (tar epoxy) protective & waterproofing coating |
| Primary function | Bridge-deck waterproofing; corrosion/chemical protection of concrete, iron & steel |
| Indicative dosage (waterproofing) | ~1.0 kg/m2 (verify against current TDS for project DFT) |
| Number of coats | Typically two or more coats (system-dependent — confirm per TDS) |
| Colour | Dark / black (inherent to coal-tar binder) |
| Suitable substrates | Concrete, iron and steel |
| Application method | Brush, roller or airless spray onto prepared substrate |
| Cure mechanism | Chemical cross-linking of two-pack epoxy (reactive cure) |
| Key resistances | Chemical resistance, abrasion resistance, minimum water absorption |
| Typical use environments | Bridge decks, water/effluent treatment plants, tanks, pools, buried walls |
Industry use cases
Bridges & Highways
Waterproofing of RCC bridge decks and approach slabs before wearing-course / asphalt, protecting the deck and reinforcement from chloride-laden water and de-icing runoff.
Water & Wastewater
Lining and protection of effluent treatment plant structures, sumps and channels against effluent, dilute acids and abrasion in STPs/ETPs.
Industrial & Storage
Internal barrier coating for tanks, pits and bunds where concrete or steel is exposed to moisture and mild chemical attack.
Infrastructure & Buried Structures
Tanking of underground retaining walls, foundations and culverts to resist ground water and aggressive soils.
Marine & Aquatic
Protection of swimming-pool shells, water-retaining structures and steelwork in continuously damp or immersed conditions.
Frequently asked questions
What type of coating is Fosroc Nitocote ET83?
Where is Nitocote ET83 typically used?
What is the coverage of Nitocote ET83?
What colour is Nitocote ET83 and can it be made light-coloured?
How should the substrate be prepared before applying ET83?
Is ET83 suitable for potable (drinking) water tanks?
Can Space Arc Engineering supply Nitocote ET83 in Delhi NCR and across India?
How we position Fosroc Nitocote ET83
Within Fosroc’s own range, Nitocote ET83 sits in the Nitocote ET family of coal-tar epoxy coatings alongside products such as Nitocote ET402, ET402E and ET550 — all coal-tar-modified epoxies used for high-build, immersion and bridge-grade protection; ET83 is positioned specifically for bridge-deck waterproofing and corrosion protection. It is normally used with a Fosroc Nitoprime primer and with Renderoc / Nitomortar repair mortars for substrate reinstatement, and complements waterproofing membranes such as the Nitoproof / Proofex ranges where a different build-up is required. Where a coal-tar-free, lighter-coloured or potable-compatible finish is needed, Fosroc’s solvent-free epoxy Nitocote EP/EPS or polyurethane options are the better fit. Among competitor systems available in India, credible alternatives in the coal-tar-epoxy and protective-coating space include Sika (e.g. Sikaguard and Sika coal-tar epoxy coatings), MBCC/MBS (Master Builders Solutions MasterProtect / MasterSeal), Dr. Fixit (Pidilite’s waterproofing and protective coatings) and STP Ltd (bituminous and epoxy coating systems). Selection between these should be driven by the project’s exposure, the specified DFT and chemical-resistance requirements, third-party approvals, and — increasingly — the regulatory acceptability of coal-tar chemistry, so the final choice should always be confirmed against the current manufacturer TDS and project specification.
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