Fosroc Nitoproof 5-35
A dual-purpose, water-based rubberised bitumen emulsion that damp-proofs and cures concrete in a single application.
What is it?
A single-component, water-based rubberised bitumen emulsion that dries to a black, flexible, seamless film. It doubles as a below-DPC damp-proof membrane and an ASTM C309 concrete curing compound.
Where is it used?
Sandwich-construction DPMs, plinth and below-ground masonry, foundation and retaining-wall backs, floor screeds, and as a curing membrane on fresh concrete slabs across residential, commercial and infrastructure projects.
Why use it?
It collapses two trade activities — damp-proofing and curing — into one coat, is non-flammable and non-toxic for confined spaces, and resists chloride and sulphate ions in aggressive ground.
How is it applied?
Stir and apply by brush or squeegee onto a sound, clean substrate. Use roughly 1 litre/m2 in coats up to 200 microns for a 600-micron DPM, or around 4 m2/litre as a single-coat curing compound.
About Fosroc Nitoproof 5-35
Fosroc Nitoproof 5-35 is a multi-purpose, rubberised bitumen emulsion supplied as a single-component liquid. It is dark brown in the can and dries to a continuous black, flexible coating. Because it is water-borne rather than solvent-borne, it carries no flash-point hazard, gives off no aggressive solvent vapour, and can be handled in confined or poorly ventilated spaces such as lift pits, basements and underground tanks — a practical advantage on Indian sites where ventilation and fire-safety discipline vary.\n\nThe product sits in Fosroc’s well-established Nitoproof family of bitumen-emulsion membranes (alongside Nitoproof 10 and Nitoproof 30), all of which share the same core idea: a rubber-reinforced bitumen film that both blocks moisture and seals fresh concrete against premature water loss. What makes the 5-35 grade attractive to contractors and procurement teams is that one drum and one application crew deliver two functions. Poured on a fresh slab it acts as a curing membrane, retaining mix water so the concrete gains strength properly; brushed onto plinth masonry, foundation faces or a screed it acts as a damp-proof and vapour barrier. The rubber content keeps the cured film extensible, so it accommodates the minor movement and shrinkage that would crack a rigid coating.\n\nFor architects, structural consultants and waterproofing contractors in Delhi NCR and across India, Nitoproof 5-35 is best understood as a workhorse \”protect-and-cure\” emulsion for concealed, below-DPC and sandwich-construction situations rather than a decorative or exposed-roof system. It is economical, fast-drying and forgiving to apply, which is exactly why it remains a specification staple for plinth protection, foundation backs and screed under-membranes. Space Arc Engineering supplies it as an authorised Fosroc distributor and applicator with technical back-up on coverage, detailing and compatibility for your specific substrate.
The technical insight
Chemically, Nitoproof 5-35 is a bitumen emulsion reinforced with rubber, stabilised in water. On application the water phase evaporates and the bitumen-rubber particles coalesce into a cohesive black film. Two properties drive its performance. First, film build: as a damp-proof membrane it is laid to a minimum 600-micron dry film thickness, applied in multiple thin coats (max ~200 microns each, second coat at right angles to the first) so that vertical work does not sag and the membrane stays pinhole-free. Second, water retention: spread thinner as a curing compound (around 4 m2/litre, the rate at which the related Nitoproof 30 grade meets ASTM C309), the same film seals the surface of green concrete and curbs evaporation during the critical early hydration window. The rubber fraction is what gives the dried membrane its extensibility, letting it bridge fine shrinkage movement instead of cracking. Being water-based, it also remains chloride- and sulphate-resistant once cured, which matters for foundations sitting in salt-bearing or sulphate-rich soils common in parts of India.
Where it is used
- Damp-proof membrane in sandwich (slab-on-DPM) floor construction
- Curing membrane for freshly placed concrete slabs and pavements
- Plinth-level and below-DPC masonry damp-proofing
- Vapour barrier behind plaster, render and floor screeds
- Protective coating on foundation faces, pile caps and retaining-wall backs
- Damp-proofing of basements, lift pits, cellars and underground structures
- Bonding/tack coat for insulation boards, cork and tiles in below-grade work
Key advantages
- Dual-purpose: damp-proofs and cures concrete in one application, saving a trade activity
- Single-component and ready to use — no mixing, no measuring, low wastage
- Water-based, non-toxic, non-flammable and usable in confined spaces
- Fast drying (about 30 minutes at 25°C) keeps follow-on trades moving
- Flexible rubber-reinforced film accommodates minor shrinkage and movement
- Resistant to chloride and sulphate ion attack from aggressive groundwater
- Easy clean-up with water while wet; applied simply by brush or squeegee
- Economical coverage and long service life in concealed conditions
Limitations & considerations
- Not a UV-stable or exposed-roof membrane — intended for concealed, below-DPC and sandwich applications
- Bitumen-based and black; not suitable where a coloured, decorative or trafficable wearing surface is needed
- Do not apply below about 6°C or above 45°C, or in windy conditions (risk of cracking)
- Water-based curing — avoid application in low-temperature, high-humidity conditions where the film will not form properly
- As a bonding aid it is not a structural adhesive; use mechanical fixings where loads demand
- Needs a sound, clean, dry substrate; loose laitance, oil and dust must be removed first
- For harsh climatic or high-temperature service, a heavier Nitoproof grade (e.g. 600 / 800HT) is more appropriate
Selection & best practice
Always confirm the project-specific Fosroc TDS before ordering, since coverage and detailing depend on substrate porosity. Surfaces must be clean, sound and free of dirt, oil, grease and loose laitance. Stir the drum well and reseal between uses. For a damp-proof membrane, build to a minimum 600-micron dry film thickness in multiple coats of no more than ~200 microns each, applying the second coat at right angles to the first and carrying the membrane up verticals to meet the existing DPC; where plaster or screed will follow, blind the final coat with clean dry sand and allow at least 48 hours before finishing. As a curing compound, apply a single even coat over the fresh slab as soon as the surface water sheen has gone. Protect freshly applied work from rain and ponding until dry, and avoid application in windy weather or outside the 6°C–45°C window. Space Arc Engineering can advise on coats, primers and compatible Fosroc detailing tapes/sealants for your substrate.
Specifications
| Product type | Single-component rubberised (rubber-reinforced) bitumen emulsion, water-based |
| Form / colour | Dark brown liquid; dries to a black flexible film |
| Specific gravity | Approx. 1.00 (typical for the grade family) |
| Solids content | Approx. 60% (typical for the grade family) |
| Rubber content | Approx. 10% (typical for the grade family) |
| Drying time | Approx. 30 minutes at 25°C |
| Overcoating time | About 1 hour at 25°C |
| Coverage — damp-proof membrane | ~1 m2/litre to give min. 600 micron DFT (substrate-dependent) |
| Coverage — curing compound | ~4 m2/litre per coat (rate at which the sibling Nitoproof 30 meets ASTM C309) |
| Max film per coat | ~200 microns per coat for vertical/multi-coat work |
| Standards | Concrete curing per ASTM C309 (family); DPM build to CP 102 practice |
| Application method | Brush or squeegee onto prepared substrate |
| Substrates | Concrete, masonry, screed, steel, cork and wood |
| Clean-up | Clean water while wet; Fosroc Solvent 102 once dry |
| Packaging | Supplied in drums (e.g. 20 litre and 200 litre — confirm current India pack) |
| Shelf life / storage | Min. 12 months stored below 40°C in unopened containers |
| Application temperature | Approx. 6°C to 45°C; avoid windy conditions |
Industry use cases
Residential & housing
Plinth-level and below-DPC damp-proofing of masonry, plus DPM under ground-floor screeds to keep rising damp out of homes and apartment blocks.
Commercial & institutional buildings
Sandwich-construction floor membranes, basement and lift-pit damp-proofing, and curing of large slab pours where one product covers both needs.
Infrastructure & foundations
Protective damp-proof coating on foundation faces, pile caps and retaining-wall backs in chloride- and sulphate-bearing soils.
Industrial & warehouse floors
Curing membrane on freshly placed concrete floors and pavements, retaining mix water for proper early strength gain before flooring is laid.
Water-retaining & below-ground structures
Damp-proofing and vapour-sealing of cellars, tanks and underground enclosures where a non-flammable, low-odour product is needed in confined space.
Frequently asked questions
Is Fosroc Nitoproof 5-35 a real Fosroc product?
Can it really cure concrete and damp-proof in one product?
How much Nitoproof 5-35 do I need per square metre?
Can it be used on exposed roofs or as a finished surface?
What surface preparation does it need?
How is it supplied and stored in India?
How we position Fosroc Nitoproof 5-35
Nitoproof 5-35 is positioned as the economical, dual-purpose \”protect-and-cure\” emulsion in Fosroc’s range — best for concealed, below-DPC, sandwich-construction and slab-curing work rather than exposed or decorative waterproofing. Within the Fosroc portfolio it sits next to Nitoproof 10 and Nitoproof 30 (similar bitumen-emulsion DPM/curing membranes), while heavier-duty or hot-climate situations point to Nitoproof 600 or the Nitoproof 800HT system; where a positive structural waterproofing layer or crystalline/cementitious approach is needed, Fosroc’s Brushbond and Proofex ranges are the natural companions, and Conplast curing compounds cover pure curing duties. Against competitors, the closest equivalents are Sika’s bitumen emulsions and Sikalastic/Igolflex damp-proofing coatings, MBS (MYK Schomburg) bituminous DPMs, Dr. Fixit’s Primeseal / bitumen-based damp-proofing products, and STP’s Shalimastik/bitumen membranes — most projects choose on availability, price and the applicator’s track record rather than headline chemistry. As an authorised Fosroc distributor and applicator in Delhi NCR and pan-India, Space Arc Engineering can specify Nitoproof 5-35 where it genuinely fits and steer you to the right alternative grade or system where it does not.
Related Waterproofing products
Source Fosroc Nitoproof 5-35 for your project
Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.