Fosroc Nitoproof 400
Heavy-duty, cold-applied solvent bituminous coating that tanks below-ground concrete against aggressive ground water — brush or roller, no joints, no torch.
What is it?
A single-component, solvent-based bituminous protective coating from the Fosroc Nitoproof family that dries to a continuous, tough black waterproof film on concrete and masonry.
Where is it used?
Below-ground structures — basement walls, foundations, pile caps, retaining walls, water-tank exteriors and sandwich DPC courses — kept away from direct daylight.
Why use it?
It stops water ingress and shields concrete from sulphate-bearing and chloride-laden ground water, forming a jointless membrane that follows rough and contoured surfaces.
How is it applied?
Cold-applied by brush or roller over a Nitoprime/Nitoproof primer coat; two or more coats laid at right angles to each other, each allowed to dry before the next.
About Fosroc Nitoproof 400
Nitoproof 400 sits in Fosroc’s long-established Nitoproof line of bituminous waterproofing coatings — the same solvent-based, cold-applied chemistry that Indian contractors have used for decades to tank basements, foundations and water-retaining structures. It is supplied ready to use as a single component: you open the container, stir, and apply. There is nothing to gauge, no two-part mixing, and no heating or torching, which removes the fire and hot-works risk that comes with membrane rolls. The material spreads by brush or roller into a seamless black film that bonds tightly to concrete and masonry, so it can be worked into fillets, coving and awkward corners where sheet membranes are hard to lap.\n\nThe product is built for the positive, water-facing side of below-ground concrete, where it does two jobs at once: it blocks liquid water and water vapour, and it protects the concrete itself from the aggressive salts — sulphates and chlorides — that migrate in from surrounding soil and ground water. Because it is a bitumen-based coating, it is not meant to live in sunlight; it is designed to be buried, screeded over, or sandwiched inside the construction, which is exactly where its durability has been proven on Indian projects. Space Arc Engineering supplies Nitoproof 400 as an authorised Fosroc distributor and applicator across Delhi NCR and Pan-India, with site guidance on priming, coat count and protection before backfill.
The technical insight
Waterproofing performance here comes from the raw material, not from a cure reaction. Nitoproof 400 is a blend of specially selected bitumens carried in solvent; as the solvent flashes off, the bitumen coalesces into a dense, cohesive film that is inherently among the most water- and water-vapour-resistant surface coatings available, and is stable against a wide range of chemical attack. Bitumen is naturally hydrophobic, so the dried film resists both standing water and the slow capillary movement that drives rising damp — which is why the same chemistry is used both as a tanking membrane and as a damp-proof course in sandwich construction. The single-component nature matters on site: there is no pot life to race against and no risk of a mis-proportioned mix, so film quality depends mainly on surface prep and even application rather than on batching discipline. The trade-off is honesty about the binder: bitumen coatings soften with heat and degrade under prolonged UV, so the film must be concealed — buried, screeded or built into a wall — to reach its full service life. Each coat is deliberately laid at right angles to the last so brush marks and low spots from one pass are filled by the next, building the continuous, pinhole-free thickness that actually keeps water out.
Where it is used
- Exterior tanking of basement and foundation walls against ground water and rising damp
- Protection of below-ground concrete from sulphate-bearing and chloride-laden aggressive soils
- Pile caps, grade beams and retaining walls on the soil-facing (positive) side
- Horizontal and vertical damp-proof courses in floor, wall and roof sandwich constructions
- External treatment of underground water-tank walls and sump/pump-room concrete
- Coating of construction-joint faces before pouring adjacent concrete in water-retaining work
- Below-tile tanking membranes in bathrooms and wet areas to stop downward leakage
- Damp-proofing of inspection chambers, utility vaults and buried service structures
Key advantages
- Cold-applied — no torch, no heating and none of the hot-works fire risk of sheet membranes
- Single component, ready to use — no mixing, no pot life and no batching errors on site
- Forms a continuous, jointless film with no laps or seams to fail
- Follows rough, contoured and detailed surfaces that are difficult to sheet-membrane
- Bonds strongly to concrete and masonry, resisting lateral tracking of water behind the film
- Resists a wide range of chemicals and shields concrete from aggressive ground-water salts
- Fast site turnaround — typically dries in about 4–8 hours in warm, well-ventilated conditions
- Backed by Fosroc technical support and Space Arc’s Delhi NCR / Pan-India applicator network
Limitations & considerations
- Not UV-stable — must be buried, screeded or built into a sandwich; never left exposed to direct daylight
- Solvent-based and flammable (flash point around 37°C); no smoking or ignition sources and full ventilation needed during application
- Bitumen softens with heat, so it is unsuitable where the film sees high service temperatures
- Cannot be applied to wet surfaces — the substrate must be clean, sound and dry, or bond will fail
- Only as reliable as its substrate; friable mortar, laitance or flaky old coatings must be cut back first
- Needs a physical protection layer (board, drainage membrane or plaster) before backfilling to survive site traffic
Selection & best practice
Start with sound, dry, clean concrete — remove laitance, loose particles, oil and old coatings by wire brushing or with Reebaklens, and cut back any weak or friable substrate to solid material before you begin. Prime the full area with one coat of a Fosroc bituminous primer (Nitoprime/Nitoproof 100) so subsequent coats adhere; judge the primer by colour, a dense even black means it has keyed, a patchy finish needs a second pass. Reinforce cracks, construction joints and wall-to-slab intersections with a strip of glass-fibre mesh or gunny cloth bedded between wet coats, and form a fillet at right-angle junctions. Apply a minimum of two full coats using a medium-stiffness brush or roller, laying each coat at right angles to the last and letting it dry completely first; increase to three coats where the water table is high. Do not let the material pool in hollows, as a skin can trap solvent and cause blow-holes. Where a screed or plaster topping will follow, blind the last wet coat with clean 3 mm grit to form a mechanical key. Finally, protect the cured film with a board or drainage membrane before backfilling.
Specifications
| Product type | Single-component, solvent-based bituminous waterproof protective coating |
| Composition | Blend of specially selected bitumens in hydrocarbon solvent |
| Colour / finish | Black, tough continuous film |
| Application method | Cold-applied by brush or roller, minimum two coats at right angles |
| Priming | One full primer coat required before top coats |
| Drying time | Approx. 4–8 hours per coat in warm, well-ventilated conditions; up to 24 hours in humid/enclosed conditions |
| Standards reference | Nitoproof brush-applied bituminous coatings comply with IS:9862-1981 |
| Flash point | Approx. 37°C — flammable, keep away from ignition sources |
| Shelf life / storage | Minimum 12 months in a dry, shaded place below 40°C |
Industry use cases
Basements & Foundations
External tanking of retaining walls, raft edges and pile caps to keep ground water and rising damp out of below-grade concrete before backfill.
Water-Retaining Structures
External damp-proofing of underground tank walls and sumps, protecting concrete from chlorinated water and aggressive soil salts.
Buildings & Wet Areas
Horizontal and vertical DPC in sandwich floors and walls, and below-tile tanking in bathrooms and toilet recesses to stop downward leakage.
Infrastructure & Utilities
Damp-proofing of inspection chambers, utility vaults, pump rooms and buried service structures in aggressive-ground conditions.
Industrial & Aggressive Soils
Protection of foundation and grade-beam concrete on sites with sulphate-bearing or chloride-laden soils where salt attack is a risk.
Frequently asked questions
Is Nitoproof 400 a torch-applied membrane?
Can I leave the coating exposed to sunlight?
How many coats do I need and does it need a primer?
Which side of the wall does it go on?
Is it safe near potable-water structures?
Does Space Arc supply and support this across India?
How we position Fosroc Nitoproof 400
Nitoproof 400 is the heavy-duty, film-building choice within Fosroc’s cold-applied bituminous range and pairs naturally with the fibre-reinforced Fosroc Nitoproof 120, which adds crack-bridging body over movement-prone details, and with a Fosroc bituminous primer for first-coat adhesion. Where a project needs an elastomeric, more UV- and heat-tolerant liquid membrane, step up to a pitch-modified polyurethane such as Nitoproof 600. For crack and joint repair ahead of coating, we stock Fosroc Nitomortar and Conbextra grouts. From our wider portfolio, cementitious crystalline systems (Dr. Fixit, MC-Bauchemie) suit negative-side or permanently wet situations, while polyurethane and acrylic exposed-roof membranes (Sika, Master Builders Solutions) are the right call where the waterproofing stays in daylight rather than buried.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.