Fosroc Nitocote CM210
Two-component polymer-modified elastomeric cementitious waterproof coating with crack-bridging ability, potable-water approval and resistance to high positive and negative hydrostatic pressure.
What is it?
A two-component, polymer-modified elastomeric cementitious waterproof coating (powder plus liquid polymer) that cures to a flexible, impermeable membrane bonded directly to concrete and masonry.
Where is it used?
Potable water tanks and reservoirs, swimming pools, internal basements, drainage culverts, wet areas (kitchens, bathrooms, shower rooms), foundations and facades requiring damp-proofing.
Why use it?
It withstands high positive (5 bar) and negative (3 bar) hydrostatic pressure, bridges fine cracks, is certified safe for potable water (BS 6920), and bonds to green or damp concrete without a primer.
How is it applied?
Site-mix the 18 kg powder into the 5 kg liquid with a slow-speed paddle, pre-dampen the substrate, then apply two coats of minimum 1 mm wet film each by brush, roller, trowel or spray.
About Fosroc Nitocote CM210
Fosroc Nitocote CM210 is an elastomeric, polymer-modified cementitious waterproof coating supplied as a two-component system: a graded cementitious powder and a liquid acrylic/polymer emulsion. When the two parts are mixed on site they cure to a tough yet flexible membrane that is permanently bonded to the structure rather than laid loose over it. That bonded, fully-adhered behaviour is the core reason engineers specify it on water-retaining and water-excluding structures where a debonded sheet membrane could allow water to track laterally behind the lining. Unlike a rigid cementitious slurry, CM210 retains elasticity after curing, so it accommodates the small thermal and shrinkage movements that real concrete experiences without cracking through. For Indian projects this combination of waterproofing performance and potable-water safety makes it a workhorse for overhead and underground tanks, STP/WTP structures, basements and pools. Space Arc Engineering supplies and applies Nitocote CM210 as an authorised Fosroc distributor and applicator across Delhi NCR and Pan-India, with technical guidance on substrate preparation, coverage and detailing at construction joints and pipe penetrations.
The technical insight
The defining technical property of Nitocote CM210 is that it is genuinely elastomeric rather than merely flexible. The cured film accommodates static cracking of up to 0.9 mm and will bridge an existing crack up to 0.5 mm wide, and it survived 6,000 cycles of dynamic 0-300-0 micron crack movement at temperatures from -15°C to +12°C without failure (University of Surrey method). At a two-coat build of 1 mm wet film per coat it resists 5 bar positive water pressure (50 m head) and 3 bar negative water pressure (30 m head) to DIN 1048 Pt 5 — meaning it holds back water pushing both from the wet face and from behind the structure, which is critical for basements under a high water table. It also forms an effective barrier to chlorides, sulphates and carbon dioxide (CO2 diffusion resistance > 50 m equivalent air path after 5,000 hours QUV), giving it a secondary role as anti-carbonation and corrosion-protective lining, hence its place in the protective-coatings category and not only general waterproofing. Potable-water safety is verified to BS 6920:2000 and reaction-to-fire is classified A2-s1,d0 to BS EN 13501-1.
Where it is used
- Potable water retaining structures — overhead tanks, underground sumps, RCC reservoirs and clear-water tanks at WTPs
- Swimming pools and water features (followed by waterproof tile adhesive and tiling)
- Internal (tanking) waterproofing of basements, lift pits and retaining walls subject to negative water pressure
- Drainage culverts, canals and channels
- Wet areas in buildings — kitchens, bathrooms, shower rooms and balconies before tiling
- Foundations and footings in contact with saline ground water
- Vapour barrier and damp-proofing layer behind facade cladding (single 1.0 mm coat permitted in that case)
- Protective lining inside sewage and effluent structures at STPs/ETPs against sulphate and chloride attack
Key advantages
- Resists high positive (5 bar / 50 m head) and negative (3 bar / 30 m head) hydrostatic pressure
- Elastomeric with genuine crack-bridging — accommodates up to 0.9 mm static cracking and bridges existing 0.5 mm cracks
- Approved for contact with potable water to BS 6920:2000
- Bonds directly to green or damp concrete and masonry — no separate primer required
- Long working life on site (2 hour pot life at 20°C) for unhurried application
- Versatile application by brush, roller, trowel or spray to suit the structure
- Acts as a barrier to chlorides, sulphates and CO2, adding corrosion/anti-carbonation protection
- Available in grey and white; takes light foot traffic before protective screeds or tiling are laid
Limitations & considerations
- Not for external surfaces where aesthetic appearance is critical — differential cure can cause slight colour variation
- Not suitable for direct tidal/marine exposure such as sea walls or seawater inlet channels
- Must not be applied below 5°C or when air/substrate temperature exceeds 45°C
- Pot life is short in Indian summer heat — only about 1 hour at 35°C, so batch sizes must be controlled
- Requires the second coat to cure 21 days at minimum 23°C for full properties, and 7 days before tiling in pools/wet areas
- Should not be exposed to moving or running water during application, and rainfall must not be imminent on exposed areas
- Not a structural or crack-injection product — wide/live cracks and large defects need repair mortars (e.g. Renderoc) and water-stopping (Renderoc Plug) first
Selection & best practice
Achieve full performance by building two coats to the specified minimum 3.8 kg/m² total (each coat at least 1 mm wet film), never a single thick coat. Saturate the substrate to a saturated-surface-dry condition before the first coat — pre-dampen porous concrete more heavily and sponge off any standing water; stop active leaks with Renderoc Plug and repair blowholes/cracks up to 10 mm with CM210 itself before coating. Mix the full 18 kg powder gradually into the 5 kg liquid for 3 to 5 minutes to a lump-free slurry and use it within 2 hours at 20°C (1 hour at 35°C); in Delhi-NCR summers, work early morning, keep material shaded and mix smaller batches. Allow the first coat to cure (minimum 3 hours at 35°C, longer when cooler) before the second, apply the second coat at right angles to the first for full coverage, then protect from rain, foot traffic and water immersion until cured — and wait 7 days before tiling pools and wet areas.
Specifications
| Product type | Two-component polymer-modified elastomeric cementitious waterproof coating |
| Components | Cementitious powder + liquid polymer emulsion |
| Colour | Grey or white |
| Pack / supply | 18 kg powder bag + 5 kg liquid container (23 kg set) |
| Mix ratio | 18 kg powder to 5 kg liquid (whole packs) |
| Mixed density | 1850 kg/m3 |
| Coverage (brush/roller/trowel) | 10.8–11.7 m2 per 23 kg set at nominal 1 mm |
| Coverage (spray) | 9.0–11.7 m2 per 23 kg set |
| Minimum consumption | 3.8 kg/m2 applied in not less than 2 coats |
| Number of coats / thickness | 2 coats, each minimum 1 mm wet film (≈1.9 kg/m2 first coat) |
| Pot life | 2 hours at 20°C; 1 hour at 35°C |
| Recoat time | Min 3 hours at 35°C (brush); spray 5 h at 20°C / 3 h at 35°C |
| Full cure | Second coat 21 days at min 23°C; 7 days before tiling |
| Min application temperature | 5°C (do not apply above 45°C) |
| Resistance to positive water pressure | 5 bar (50 m head) — DIN 1048 Pt 5 |
| Resistance to negative water pressure | 3 bar (30 m head) — DIN 1048 Pt 5 |
| Static crack accommodation | 0.9 mm; bridges existing crack up to 0.5 mm |
| Dynamic crack capability | 6,000 cycles of 0-300-0 microns at -15°C, 0°C, 12°C (no failure) |
| CO2 diffusion resistance | > 50 m equivalent (after 5,000 hrs QUV) |
| Standards / approvals | BS 6920:2000 (potable water), DIN 1048, BS EN 13501-1 (A2-s1,d0), CEN/TC 67 pressure test; Dubai Civil Defence certified; ASTM E84 Class A |
Industry use cases
Water & wastewater infrastructure
Lining RCC clear-water tanks, sumps and reservoirs at WTPs/STPs where potable-water approval (BS 6920) and resistance to sulphates/chlorides are both mandatory.
Commercial & residential basements
Internal tanking of basements, lift pits and retaining walls against negative water pressure where a positive-side membrane is inaccessible after construction.
Hospitality & sports facilities
Waterproofing swimming pools, balancing tanks and water features prior to tiling with a waterproof tile adhesive.
Building construction (wet areas)
Concealed waterproofing of bathrooms, kitchens, shower rooms and terraces before screeding and tiling in apartments, hotels and offices.
Irrigation & drainage
Lining canals, culverts and drainage channels to prevent seepage loss and protect concrete from waterborne salts.
Frequently asked questions
Is Fosroc Nitocote CM210 safe for drinking-water tanks?
How much CM210 do I need per square metre?
Can it stop water pushing from behind the wall (negative pressure)?
Does CM210 need a primer, and can it go on damp concrete?
How long before I can tile a pool or bathroom coated with CM210?
What is the difference between Nitocote CM210 and a rigid waterproofing slurry?
Can it be used outdoors on a visible facade?
How we position Fosroc Nitocote CM210
Within the Fosroc range, Nitocote CM210 is the elastomeric, crack-bridging cementitious membrane — a step above a rigid two-coat slurry where movement or high water pressure is in play. It sits alongside Brushbond family flexible coatings and is frequently paired with Renderoc repair mortars to make good spalled concrete and Renderoc Plug to arrest active leaks before coating; on structures also needing joint sealing, Fosroc Nitoseal/Thioflex sealants and Supercast waterstops complete the system. For above-ground anti-carbonation duty on facades, Dekguard is Fosroc’s more aesthetic choice, whereas CM210’s strength is buried/immersed waterproofing with potable approval. Against the wider Indian market, credible alternatives an engineer may evaluate include Sika’s SikaTop Seal-107 and Sikalastic flexible cementitious coatings, MBCC/Master Builders Solutions MasterSeal 540/590, Dr. Fixit Pidiproof LW+/Roofseal and STP (Shalimar) flexible cementitious systems. The honest position: CM210 is specified primarily for its proven 5 bar positive / 3 bar negative pressure resistance, genuine crack-bridging and BS 6920 potable-water approval; where the structure is dimensionally stable and low-pressure, a simpler (and cheaper) two-coat slurry may be adequate, and where deep dynamic movement or full tanking to BS 8102 grade 3 is required, designers should confirm the build-up and number of coats with Fosroc and the consultant. Space Arc Engineering helps specify the right grade and detailing for the actual exposure rather than over- or under-specifying.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.