MC-Bauchemie Nafufill KM 220
A fibre-reinforced, one-component repair mortar for fine reprofiling and functional patch repair — 2mm skim coats to 30mm buildable layers, no separate bond coat required.
What is it?
A one-component, polymer-modified, fibre-reinforced cementitious mortar rated Class R2 under EN 1504-3, built for both cosmetic surface reprofiling and functional patch repair of damaged concrete.
Where is it used?
Spalled RCC columns and beams, honeycombed or blow-holed concrete, parking structure soffits, basements, water tanks and precast panels — anywhere needing 2-30mm of repair before coating, waterproofing or tiling.
Why use it?
It finishes fine enough to skim like a fairing coat (1mm max grain size) yet carries real repair-mortar strength — 25 N/mm² at 28 days, fibre reinforcement against shrinkage cracking, and enough bond to skip a separate bonding slurry.
How is it applied?
Powder is mixed with 17-19% water by weight in a forced-action mixer for at least 5 minutes, then hand-troweled or wet-sprayed in 2-30mm layers, finished fresh-in-fresh, and cured under damp cover away from sun and wind for about 3 days.
About MC-Bauchemie Nafufill KM 220
Most concrete repair jobs in Delhi NCR start the same way — chloride or carbonation-driven rebar corrosion cracks the cover concrete, a chunk spalls off a column or beam soffit, and the contractor is left with an irregular patch too big for a 3mm fairing coat but not necessarily needing a full structural mortar either. Nafufill KM 220 sits in that middle ground. It is certified Class R2 under EN 1504-3 (Principle 3, methods 3.1, 3.3, 7.1, 7.2, 7.4) — the classification reserved for repair mortars that restore section and protect the substrate without claiming full structural load-bearing capacity. That is not a downgrade; it is the correct tool for cover-concrete and non-structural section loss, while genuine load-bearing damage calls for its R3/R4 siblings in the same family.
What makes it useful on Indian sites is the combination of fine finish and real workability. The 1mm maximum grain size lets it be floated to a coating- or membrane-ready surface without a separate skim pass, and skipping the bonding primer saves a full sequencing step versus two-part repair systems — real money on labour-heavy sites. Working time is rated 45 minutes at 20°C, dropping to 30 minutes at 30°C, which matters on a Gurugram or Noida site in peak summer. Space Arc Engineering supplies and applies Nafufill KM 220 pan-India as an authorised MC-Bauchemie distributor and applicator, typically specifying it for parking-structure repair, basement and water-tank patchwork, and soffit reinstatement ahead of waterproofing or coating work.
The technical insight
The number worth understanding before ordering is the E-modulus: 16,200 N/mm² at 28 days. A repair mortar far stiffer or softer than the parent concrete (typically 25,000-35,000 N/mm²) tends to debond at the patch edge under thermal cycling — the classic ring-crack failure seen in poorly matched repairs. KM 220’s fibre reinforcement does double duty: it controls plastic and early drying shrinkage in the thin 2-10mm sections where most reprofiling happens, and adds crack-bridging so hairline shrinkage doesn’t telegraph into the coating or membrane applied over it. The 1.67 kg/m² per mm consumption figure and 100:17-19 powder-to-water ratio matter for costing site quantities accurately, and the TDS is explicit that hand-mixing and partial-bag mixing are not permitted — a stricter QC bar than many crews are used to on ordinary patch mortars.
Where it is used
- Reprofiling spalled or corrosion-damaged concrete on RCC columns, beams and slabs
- Filling honeycombed, blow-holed or voided concrete surfaces ahead of a protective coating
- Patch repair following rebar de-rusting, cleaning and passivation in a standard corrosion-repair sequence
- Fine leveling of RCC surfaces before waterproofing membrane installation or tiling
- Repair of basements, water-retaining structures and sumps (moisture classes WO, WF, WA)
- Overhead and soffit repairs — parking structure ceilings, balcony undersides, beam bottoms
- Precast concrete element defect rectification before dispatch or erection
- General civil, industrial and residential repair works across exposure classes XC1-4 and XF1-4
Key advantages
- Applied without a separate bonding coat, cutting a full working step off typical two-part repair systems
- Fibre reinforcement resists plastic and early drying shrinkage cracking in thin repair sections
- Works by hand trowel or wet-spray pump, scaling from a single patch to a full column-line repair
- 1mm maximum grain size gives a coating- or membrane-ready finish without a separate skim pass
- EN 1504-3 Class R2 certification is third-party verifiable, useful for PMC compliance documentation
- Low fresh mortar density lets it hold on overhead and soffit surfaces without excessive sagging
- Working time of up to 60 minutes at 5°C and still 30 minutes at 30°C gives crews real margin on Indian sites
- Non-combustible (EN 13501-1 Class A1) and DGNB-registered for projects tracking green-building or fire compliance
Limitations & considerations
- Class R2 is not a structural repair mortar — where damage has actually reduced load-bearing capacity, specify Nafufill KM 230 (R3) or KM 250 (R4) instead
- Maximum 30mm per pass (50mm as a reprofiling exception) — deeper spalls need a build-up sequence or a heavier-bodied mortar
- Cannot compensate for poor substrate preparation — mechanical roughening and rebar treatment still have to be done properly first
- Working time drops to 30 minutes at 30°C, so batch sizing and crew pacing need real planning on peak-summer sites
- Being polymer-modified and fibre-reinforced, it costs more than plain patch-repair mortars — the premium only pays off where fine finish or crack control is actually needed
- Requires about 3 days of proper curing away from sun and wind; skipping this undoes the shrinkage-control benefit it’s bought for
Selection & best practice
Prepare the substrate to sound, mechanically roughened concrete, treat exposed rebar, and bring the surface to saturated-surface-dry before mixing. Use a forced-action or slow-speed paddle mixer only — the TDS explicitly rules out hand-mixing or part-bag batches, since both cause inconsistent fibre dispersion. Dose water at 17-19% by weight (4.25-4.75 L per 25kg bag) and mix a full 5 minutes to a lump-free consistency. Apply fresh-in-fresh in 2-30mm layers, keying each pass into the substrate rather than relying on a bond coat, and finish with a float or damp sponge. Protect the surface from sun, wind and rapid drying for about 3 days, and confirm the exact recoat window with your applicator before running a membrane or coating over it.
Specifications
| System | One-component, polymer-modified, fibre-reinforced cementitious mortar |
| EN 1504-3 classification | Class R2 (Principle 3, methods 3.1, 3.3, 7.1, 7.2, 7.4) |
| Maximum grain size | 1 mm |
| Mixing ratio | 100 : 17-19 powder : water (p.b.w.); approx. 4.25-4.75 L water per 25 kg bag |
| Compressive strength | 5.3 N/mm² (24h) / 22.5 N/mm² (7d) / 25 N/mm² (28d) |
| Flexural strength | 1.4 N/mm² (24h) / 3.8 N/mm² (7d) / 4.2 N/mm² (28d) |
| Layer thickness | 2-30 mm per pass; up to 50 mm as a reprofiling mortar |
| Consumption | 1.67 kg/m² per mm of thickness |
| Pack size / density / fire class | 25 kg bag; fresh mortar density 1.95 kg/dm³; EN 13501-1 Class A1 (non-combustible) |
Industry use cases
Parking structures & commercial buildings
Reprofiling corrosion-spalled columns and beam soffits before applying a protective anti-carbonation coating
Basements & water-retaining structures
Patch repair of internal walls and slabs ahead of a waterproofing membrane, using KM 220’s WO/WF/WA moisture-class rating
Residential high-rises
Terrace and balcony slab soffit repair where leaking joints have corroded the reinforcement cover
Precast & infrastructure
Blowhole, honeycomb and surface-defect rectification on precast panels and bridge substructure elements before handover
Industrial facilities
General RCC repair works in plants and warehouses where section restoration is needed without full structural downtime
Frequently asked questions
Is Nafufill KM 220 a structural repair mortar?
Do I need a bonding coat or primer first?
How much water goes into a 25kg bag?
What’s the maximum thickness I can apply in one pass?
How soon can I coat or waterproof over it?
Does Space Arc supply and apply this pan-India?
How we position MC-Bauchemie Nafufill KM 220
Nafufill KM 220 is the R2 midpoint in MC-Bauchemie’s four-grade Nafufill repair mortar family — Nafufill LM covers lighter R1 cosmetic work, KM 220 handles fine R2 reprofiling, and KM 230 (R3) / KM 250 (R4) step up to genuine structural section restoration. Specifying KM 220 for structural damage under-delivers; over-specifying KM 250 for a cosmetic patch wastes budget. For pure blowhole and surface-void filling under 3mm, Fosroc’s Renderoc FC fairing coat is a genuine, simpler alternative many consultants already spec — though it can’t match KM 220’s 30mm buildable depth or fibre-reinforced crack control. Space Arc stocks and applies both brands and recommends based on defect severity, not margin.
Fosroc Renderoc FC — For pure blowhole and surface-void filling under 3mm with no reprofiling depth requirement, Renderoc FC is a genuine, simpler alternative many consultants already spec, though it can’t match KM 220’s 30mm buildable depth or fibre-reinforced crack control beyond a cosmetic skim.
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