Fosroc Nitoproof 600
A single-component, pitch-modified polyurethane that moisture-cures into a seamless, permanently flexible waterproof membrane for below-grade and concealed concrete surfaces.
What is it?
A one-component, pitch-modified liquid polyurethane waterproofing membrane that cures by reacting with atmospheric moisture to form a tough, seamless elastomeric barrier over concrete.
Where is it used?
Foundations, floor slabs, suspended floors, balconies, patios, inspection pits, inverted roofs, planter boxes and tunnels where the membrane will be buried or covered by a protective screed.
Why use it?
It gives continuous, joint-free adhesion that stops water tracking sideways along the slab, bridges cracks up to 2 mm, and chemically cures so it will not re-melt or flow at high ambient temperatures.
How is it applied?
Applied cold by brush, roller, squeegee or airless spray onto a clean, sound, dry substrate at a minimum 1.3 mm wet film thickness, then left to cure for at least 24 hours at 25 C.
About Fosroc Nitoproof 600
Fosroc Nitoproof 600 is a liquid-applied, elastomeric waterproofing membrane built on a single-component, pitch-modified polyurethane chemistry. Unlike a self-adhesive bituminous sheet or a two-pack coating that has to be mixed on site, it arrives ready to use and cures simply by reacting with moisture in the air. As it cures it forms a continuous, fully bonded film with no laps, overlaps or seams, so there is no weak joint for water to find. That intimate, gap-free bond to the concrete is the property engineers value most, because it prevents the lateral migration of water beneath the membrane that plagues loose-laid or poorly adhered systems.
For Space Arc’s typical projects across Delhi NCR and Pan-India, Nitoproof 600 sits firmly in the concealed, below-grade and sandwiched waterproofing bracket. It is the membrane you specify under a screed, behind a protective wall, inside a planter box or across a suspended floor before finishes go down. Because the cured film is chemically crosslinked, it does not soften, flow or biodegrade, and it shrugs off mild acids, alkalis and the water-borne salts common in Indian ground conditions. The one thing it is not designed to do is sit permanently in sunlight, which shapes where and how it should be used on a real site.
The technical insight
The performance comes from the moisture-cure polyurethane backbone modified with pitch. When the wet film is exposed to atmospheric humidity, the isocyanate groups react and crosslink, converting the liquid into an irreversibly cured elastomer. Because that cure is a chemical reaction rather than simply solvent flashing off, the finished membrane will not melt or cold-flow at elevated ambient temperatures, and it holds its properties across a service range of -40 C to +70 C. The cured film stretches 500 to 700 percent (ASTM D412), so it accommodates thermal movement and bridges shrinkage and settlement cracks up to 2 mm without splitting. The pitch modification, high 92 percent solids content and continuous adhesion together create an impervious barrier that resists aggressive soil chemistry and blocks water from creeping laterally along the concrete, which is precisely how buried slabs and retaining structures fail when a lesser membrane is used.
Where it is used
- RCC raft foundations and ground-bearing floor slabs before the protective screed
- Retaining walls and basement structures on the positive (water) face
- Suspended floors, podium decks and wet-area slabs such as bathrooms
- Balconies and patios where the membrane is tiled or screeded over
- Planter boxes and landscaped decks needing root-tolerant, buried waterproofing
- Inspection pits, sumps and below-grade service chambers
- Inverted (protected-membrane) roofs finished with insulation and ballast
- Tunnels and buried concrete exposed to aggressive ground water
Key advantages
- Single-component and cold-applied, so no on-site mixing, heating or torching is required
- Cures seamless with no laps or joints, eliminating the weak lines where sheet membranes leak
- Continuous adhesion to concrete prevents water tracking sideways under the film
- Bridges live and shrinkage cracks up to 2 mm thanks to 500 to 700 percent elongation
- Irreversible chemical cure means the film will not melt or flow at high ambient temperatures
- Wide service range of -40 C to +70 C suits both cold stores and hot rooftop slabs
- Resists mild acids, alkalis and water-borne salts, and does not biodegrade in soil
- Can be reinforced with fabric at corners and detailing for extra robustness
Limitations & considerations
- Not UV-stable; it must not stay exposed to sunlight beyond 28 days and needs a screed or a Nitoproof Reflectacoat topcoat
- Designed for positive-side use, not for negative-side or internal tanking against water pressure
- Substrate must be clean, sound and genuinely dry; it will not cure reliably on damp or green concrete
- Contains flammable solvent with a flash point of 54 C, so open flames and smoking must be excluded and ventilation ensured
- Bitumen and asphalt substrates need a separate Nitoproof 600 Primer barrier before application
- Being black and pitch-based, it is a concealed membrane and not a decorative or trafficable wearing surface
Selection & best practice
Start with a clean, sound and dry substrate. Dense, good-quality concrete needs no priming, but porous or absorbent concrete should first be sealed with a 1:1 mix of Nitoproof 600 and xylene, and any bitumen or asphalt surface must be primed with Nitoproof 600 Primer (allow it to cure 4 to 8 hours, but do not let it fully harden before overcoating). Detail the tricky areas before the main coat: install a cant strip or fillet at all right-angle bends, pretreat non-moving cracks with the membrane extending 75 mm each side, and mask movement joints then band them extending 150 mm each side. Let all pretreated areas cure overnight. Apply the membrane by brush, roller, squeegee or airless spray at a minimum 1.3 mm wet film thickness; where fabric reinforcement is specified, bed it into a wet 1.3 mm coat and overcoat with a second 1.3 mm layer after 24 hours. Allow a minimum 24-hour cure at 25 C before covering, and get the protective screed or Reflectacoat topcoat on within the 28-day UV window. Clean tools immediately with Fosroc Solvent 101.
Specifications
| Chemistry | Single-component, pitch-modified liquid polyurethane (moisture-cured) |
| Colour | Black |
| Coverage | 1.3 litre/m2 for a 1.3 mm wet film thickness |
| Crack bridging | Up to 2 mm |
| Elongation (ASTM D412) | 500 to 700 percent |
| Tensile strength (ASTM D412) | 1.60 N/mm2 |
| Solids content | 92 percent |
| Service temperature range | -40 C to +70 C |
| Tack-free time at 25 C | 15 to 24 hours (min 24-hour cure) |
| Pack sizes | 20 or 22.7 litre pails |
| Shelf life | Minimum 6 months in original unopened containers |
Industry use cases
Commercial and residential basements
Positive-side waterproofing of raft foundations and retaining walls before backfill and protective works, giving a seamless bonded barrier against aggressive ground water.
Podium and terrace decks
Buried membrane under screed and tiling on balconies, patios and podium slabs, where its crack-bridging and continuous adhesion protect the structure below.
Landscaping and green decks
Waterproofing to planter boxes and landscaped decks that stays flexible, resists soil salts and does not biodegrade under permanent burial.
Infrastructure and below-grade works
Tunnels, inspection pits, sumps and buried concrete chambers where a joint-free, chemically cured film is needed to resist hydrostatic and soil exposure.
Inverted and protected roofs
Membrane on inverted-roof slabs finished with insulation and ballast, protected from UV while delivering long-term flexibility across wide temperature swings.
Frequently asked questions
Is Nitoproof 600 a bituminous coating or a polyurethane?
Can I leave Nitoproof 600 exposed on a terrace?
What coverage should I plan for?
Do I need to prime the concrete first?
Can it be used for negative-side or internal water-tank waterproofing?
How long before it can be covered over?
How we position Fosroc Nitoproof 600
Within the Fosroc waterproofing family, Nitoproof 600 is the general-purpose, single-coat PU membrane for buried and concealed concrete. Where a project involves severe below-grade exposure, high hydrostatic head or heavier substrate cracking, step up to Fosroc Nitoproof 800, the fibre-reinforced grade built for those tougher conditions. For the negative-side and internal water-tank work that Nitoproof 600 cannot serve, specify the cementitious Fosroc Brushbond instead. On exposed rooftop applications, always pair Nitoproof 600 with Nitoproof Reflectacoat as the UV-protective topcoat. Across our other brands, Space Arc can offer comparable crystalline and cementitious systems from Dr. Fixit and Sika where a client’s standing specification calls for them; talk to our technical team for the right match to your drawings.
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