About Fosroc Nitoproof 100

Fosroc Nitoproof 100 is one of the oldest and most dependable names in bituminous damp-proofing, with a field record stretching back more than three decades. It is a low-viscosity blend of selected bitumens carried in solvent, supplied as a single-component liquid that needs no mixing or heating. Once brushed, rolled or sprayed onto a prepared surface, the solvent flashes off and leaves behind a tough, continuous black bitumen film that blocks the passage of both liquid water and water vapour. For Indian sites, that makes it a workhorse for the unglamorous but critical jobs — tanking a below-ground wall, laying a damp-proof course under brickwork, or lining a water tank before it goes into service.

What keeps Nitoproof 100 in specifications is its versatility and economy. The same drum can protect below-ground concrete, act as a vertical vapour barrier, line potable water tanks and pipes without tainting the water, guard buried metal against corrosion, and serve as a water-retention curing membrane on fresh slabs. It tolerates damp substrates, so crews are not held up waiting for concrete to bone-dry, and coverage of several square metres per litre keeps material cost low. It is important to be clear about what this product is not: it is a thin-film solvent bitumen coating, not a crystalline or high-build elastomeric membrane, and it is designed to be concealed rather than left permanently exposed.

The technical insight

The performance of Nitoproof 100 comes from the physics of a solvent-borne bitumen, not from any chemical reaction with the concrete. In the can it is a mobile, low-viscosity liquid, which lets it wet out and grip into the surface texture and open pores of concrete, brick or plaster. As the solvent evaporates, the bitumen coalesces into a cohesive, flexible film that is hydrophobic by nature — water simply cannot dissolve or pass through it. Applying the second coat at right angles to the first is deliberate: it covers the pinholes and thin spots left by the first pass, so the two coats together give a genuinely continuous barrier rather than two identical weak maps. Because bitumen also slows the escape of mix water from fresh concrete, the same film works as a curing compound, delivering a curing efficiency in excess of 80% and meeting ASTM C309. The trade-off inherent in this chemistry is that the film stays a thermoplastic bitumen: it must be protected from UV, kept off surfaces that will see permanent sunlight, and given a screed or backfill to shield it in service.

Where it is used

• Damp-proof membranes and horizontal damp-proof courses below brickwork and floor slabs
• Below-ground protection to foundation walls, retaining walls and buried concrete
• Vertical vapour barriers behind finishes and in sandwich wall construction
• Internal lining of potable water tanks and pipes without tainting the stored water
• Corrosion protection to buried or concealed steel and metal surfaces
• Water-retention curing membrane on freshly placed concrete slabs and screeds
• Reinstatement and overcoating of damaged bituminous membranes to restore continuity
• Corner reinforcement at floor-to-wall junctions using a bitumen fillet detail

Key advantages

• Single-component and ready to use — no mixing, heating or on-site batching
• High coverage per litre keeps material cost low on large areas
• Bonds to damp concrete, brick and plaster, so work need not wait for a bone-dry substrate
• Quick drying, typically overcoatable in about 2.5-3 hours in warm conditions
• Does not taint water, allowing use in potable water tanks and pipelines
• Tough film resistant to most naturally occurring ground chemicals
• Doubles as a curing compound with over 80% curing efficiency, meeting ASTM C309
• Backed by over 30 years of field use and compliance with BS 3416:1991 Type 1A

Limitations & considerations

• Solvent-based and flammable (flash point 37 degrees C) — no naked flames, no smoking, and good ventilation are mandatory during use
• Not UV-stable; the film must be concealed by backfill, screed or finish and never left permanently exposed to daylight
• A thin-film coating, not a high-build or crack-bridging elastomeric membrane — it will not span moving cracks
• Cannot be applied to surfaces below 6 degrees C or above 45 degrees C substrate temperature
• Free surface water or active water bleed must be stopped first; it is not a plug for running leaks
• Solvent odour and the need for a solvent (Fosroc Solvent 102) for clean-up make it less suited to poorly ventilated interiors

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Nitoproof 100

Nitoproof 100 is the economical, quick-drying thin-film bitumen coat for concealed damp-proofing and curing. When a project needs a heavier, more robust below-ground membrane, step up within the same family to Fosroc Nitoproof 120, a fibre-reinforced bituminous coating that builds a thicker, tougher film for basements, retaining walls and protected roof slabs. For jobs that will see UV exposure or movement — where a bitumen film is unsuitable — move to Fosroc’s acrylic and polyurethane liquid membranes such as Nitoproof 600 PF. Where the real need is water-retention curing rather than waterproofing, a dedicated Fosroc Concure curing compound may be more appropriate. We also stock complementary damp-proofing and tanking systems from Dr. Fixit and Sika, and our team can help you match the right build-up to the exposure, substrate and warranty your specification demands.

Related Waterproofing products

View all Waterproofing products →