Fosroc Nitoproof A30
Multi-purpose, single-component rubberised bitumen emulsion — a cost-effective brush- or spray-applied waterproofer, damp-proof membrane and bonding agent for walls, floors and below-ground concrete.
What is it?
A single-component, water-based rubberised bitumen emulsion that dries from a dark-brown liquid into a black, flexible, seamless waterproof coating. It is a member of Fosroc’s Nitoproof bitumen-emulsion family (closely related to Nitoproof 30 / 30HL).
Where is it used?
Damp-proof membranes in sandwich (screed-over) construction, general waterproofing of walls and floors, vapour barriers, below-ground concrete and foundations, and as an adhesive for cork, insulation boards and expanded polystyrene.
Why use it?
It is economical, water-based and non-toxic, non-flammable, easy to brush or spray, and bonds well to concrete, masonry and screeds — giving a quick, seamless protective film without hot works or solvents.
How is it applied?
Applied cold by brush, broom or spray over a clean, sound substrate, typically as a diluted priming coat followed by full-strength coats, each allowed to dry before the next — often protected by a screed, board or backfill.
About Fosroc Nitoproof A30
Fosroc Nitoproof A30 is a multi-purpose, rubberised bitumen emulsion engineered as a low-cost, labour-saving waterproof membrane and damp-proofing coating. It is supplied as a single-component, water-based liquid that requires no heating, no solvents and no on-site mixing of components — you simply stir, optionally dilute for priming, and apply. In the can it is a dark-brown emulsion; once the water carrier evaporates it coalesces into a continuous black film that stays flexible enough to accommodate the minor movement and shrinkage typical of concrete and cementitious substrates. Because the rubber content reinforces the cured bitumen, the film resists the cracking and embrittlement associated with plain cut-back bitumen coatings. The product sits within Fosroc’s well-established Nitoproof bitumen-emulsion range, alongside Nitoproof 30 (from which the A30 / 30HL designation derives) and the fibre-reinforced Nitoproof 30F, and shares the same core chemistry and field behaviour. For Indian contractors, consultants and architects, Nitoproof A30 is best understood as a workhorse “tanking and damp-proofing” emulsion: it is the layer you brush or spray onto plinth beams, retaining walls, foundation faces, toilet and balcony sunken slabs, and under-screed areas where a flexible, seamless, vapour-resistant black membrane is needed economically, rather than a high-build elastomeric or polyurethane system. Its secondary role as a bonding adhesive for insulation boards, cork and EPS also makes it useful on roofing and thermal-insulation build-ups.
The technical insight
The performance of Nitoproof A30 hinges on how a bitumen emulsion cures. The product is bitumen dispersed in water and stabilised with emulsifiers; waterproofing develops only as that water leaves the film and the bitumen particles coalesce — which is why it must NOT be applied to surfaces that are waterlogged, frozen, or about to be rained on, and why it is unsuitable for permanently immersed or potable-water situations. The rubber modification raises the softening point and elasticity of the cured film compared with unmodified bitumen, improving its tolerance of substrate movement and temperature cycling. In practice the recommended technique is a thinned priming coat (the emulsion diluted with clean water) to penetrate and key into the pores of the concrete or screed, followed by one or more full-strength coats applied in alternating directions to build a continuous, pinhole-free membrane. The published priming application rate is on the order of 2 m² per litre per coat, with a touch-dry / over-coating interval of about 3 hours at 20 degrees C — figures that lengthen in cool, humid or poorly ventilated conditions because cure is evaporation-driven. As a damp-proof membrane in sandwich construction it is laid between two cementitious layers (for example beneath a floor screed) so the cured film is protected from UV and mechanical damage; left permanently exposed to sunlight, a thin bitumen emulsion film will eventually oxidise and degrade, so a screed, board or protection layer is the norm. Because exact dilution ratios, coverage and coat counts vary slightly by region and revision, the governing figure for any job must be taken from the current country-specific Fosroc Technical Data Sheet for Nitoproof A30 / 30.
Where it is used
- Damp-proof membrane (DPM) in sandwich / screed-over construction between two cementitious layers
- Below-ground waterproofing of foundation faces, plinth beams, footings and retaining-wall backs
- General-purpose waterproofing of internal and external walls and floors
- Vapour seal / vapour barrier beneath floors, screeds and insulation
- Damp-proofing of brick and block masonry, basement walls and lift-pit perimeters
- Curing and protective coating on concrete where a flexible bituminous film is acceptable
- Adhesive / bonding agent for cork panels, insulation boards and expanded polystyrene (EPS)
- Tanking of sunken slabs in toilets, bathrooms, balconies and planter boxes (under screed and tiling)
Key advantages
- Single-component and ready to use — no two-pack mixing, no heating, no solvents
- Water-based, non-toxic and non-flammable, so safer to store, handle and apply in enclosed spaces
- Economical compared with elastomeric, cementitious-crystalline or PU membrane systems
- Cold-applied by brush, broom or spray, giving fast, low-skill, labour-saving installation
- Forms a seamless, jointless black membrane that bridges minor substrate imperfections
- Rubber-modified film stays flexible and resists the embrittlement of plain bitumen coatings
- Bonds well to concrete, masonry and screeds; can also act as a board / insulation adhesive
- Can be applied to green (relatively fresh) concrete, helping programme on fast-track sites
- Resists attack from common ground-borne chloride and sulphate ions in below-grade use
Limitations & considerations
- Cure is evaporation-driven — not suitable for permanently immersed, ponding-water or potable-water tanks
- Must not be applied to wet, frozen, contaminated or actively damp surfaces, or when rain is imminent
- Not UV-stable as a thin film; permanently exposed coatings oxidise and must be protected by screed, board or backfill
- Limited crack-bridging and elongation versus elastomeric PU/acrylic or APP/SBS torch membranes — not for structurally moving joints
- A coating, not a reinforced sheet membrane; vulnerable to mechanical damage and puncture before protection is in place
- Performance depends on correct dilution, coverage and number of coats — under-application leaves pinholes and weak spots
- Black bituminous staining can transfer; keep off finished or visible surfaces
- Drying and over-coating times extend significantly in cold, humid or poorly ventilated conditions
- Exact coverage, dilution and standards vary by region/revision — always verify against the current Fosroc TDS
Selection & best practice
Start with a clean, sound, structurally dry substrate — remove laitance, dust, oil and loose material and make good honeycombing and cracks. Dampen highly absorbent surfaces only to a saturated-surface-dry (no free water) condition, then apply a priming coat of Nitoproof A30 thinned with clean water to penetrate the pores. Follow with one or more full-strength coats, brushing or spraying each in alternating directions and allowing roughly 3 hours drying at 20 degrees C (longer in cool or humid weather) between coats to build a continuous, pinhole-free film. Pay particular attention to corners, construction joints and pipe penetrations, reinforcing them where movement is expected. Where the membrane will be left in a sandwich detail, lay the protective screed or board promptly; for below-ground faces, protect with a board or quilt before backfilling. Do not apply if rain is expected before the film has dried, and never use it for permanently water-immersed or drinking-water applications — specify a Fosroc cementitious or PU system instead. Confirm dilution, coverage and coat count against the current country-specific Fosroc Technical Data Sheet, and ask Space Arc Engineering for project-specific specification support.
Specifications
| Product type | Multi-purpose, rubberised bitumen emulsion (single-component, water-based) |
| Chemistry | Rubber-reinforced bitumen dispersed in water; coalesces on drying |
| Appearance (wet) | Dark-brown emulsion |
| Appearance (cured) | Black, flexible, seamless film |
| Number of components | One (ready to use; dilute with clean water for priming only) |
| Application method | Brush, broom or spray, cold-applied |
| Priming coat rate | Approx. 2 m² per litre per coat (verify on current TDS) |
| Drying / over-coating time | Approx. 3 hours at 20°C (minimum over-coat interval ~3 hours) |
| Coats | Priming coat plus full-strength coat(s) per TDS requirement |
| Toxicity / flammability | Non-toxic, non-flammable, environmentally friendly |
| Suitable substrates | Concrete (incl. green concrete), masonry, brick, cement screed |
| Typical pack | Supplied in drums (e.g. 200 litre); confirm regional pack sizes with distributor |
| Former designation | Related to / formerly Nitoproof 30 (Nitoproof 30HL) |
Industry use cases
Residential & commercial buildings
Damp-proofing of plinth beams, foundation faces and basement/retaining walls, and DPM beneath ground-floor slabs and screeds to stop rising damp and ground moisture.
Wet areas & sunken slabs
Cost-effective tanking of toilet, bathroom and balcony sunken slabs under the screed and tile build-up, where a seamless flexible black membrane is needed economically.
Roofing & thermal insulation
Vapour barrier beneath insulation and screeds, and as a bonding adhesive to stick cork, insulation boards and EPS to concrete decks in insulated roof and floor build-ups.
Infrastructure & below-ground works
Protective damp-proof coating on buried concrete — footings, pile caps, box culverts, lift pits and underground chamber walls — where chloride/sulphate-bearing soils are a concern.
Industrial & warehouse floors
Under-screed DPM and vapour seal for large slab-on-grade areas, applied by spray for fast coverage before the topping screed or floor finish is laid.
Frequently asked questions
Is Fosroc Nitoproof A30 a real product, and what exactly is it?
Where is Nitoproof A30 typically used?
Can Nitoproof A30 be used for water tanks or permanently submerged areas?
How is it applied and how long does it take to dry?
What is the coverage of Nitoproof A30?
Does the coating need protection after it cures?
How we position Fosroc Nitoproof A30
Nitoproof A30 is Fosroc’s economical, water-based bituminous workhorse for damp-proofing and concealed (under-screed or below-ground) waterproofing — chosen when a flexible, seamless, low-cost black membrane is sufficient and full elastomeric performance is not required. Within the Fosroc range it sits beside Nitoproof 30 and the fibre-reinforced Nitoproof 30F (its closest relatives), with Brushbond / Brushbond flexible cementitious coatings and the Proofex tanking-membrane and Nitoproof PU liquid systems taking over where higher crack-bridging, exposed durability or true immersion resistance is needed; below-grade, it is frequently paired with Conplast curing/admixture and Nitobond bonding agents on the same project. Against the wider Indian market, comparable rubberised-bitumen / bituminous damp-proofing emulsions include Sika’s bituminous coatings (e.g. SikaProof / Igolflex grades), Dr. Fixit Pidiproof / bitumen-based products from Pidilite, MYK Laticrete (MBS) bituminous coatings, and STP (Shalimar Tar Products) bitumen membranes and coatings — all credible alternatives in the same price-and-performance band. For high-movement, UV-exposed or potable applications, buyers should step up to a PU or polymer-cementitious membrane regardless of brand. As an authorised Fosroc distributor and applicator serving Delhi NCR and pan-India, Space Arc Engineering can supply genuine Nitoproof A30, advise on the right grade versus its alternatives, and provide specification and on-site application support; always cross-check final dilution, coverage and standards against the current Fosroc TDS for your country.
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