MC-Bauchemie Nafufill LM
A fire-rated, fibre-reinforced lightweight repair mortar for facade, balcony and gas-concrete reprofiling – applied without a separate bonding coat.
What is it?
A one-component, polymer-modified, fibre-reinforced lightweight cementitious mortar with an integrated bonding agent, classified R1 under EN 1504-3.
Where is it used?
Facades, balconies, loggias, attics and parapets on normal and lightweight concrete, plus gas concrete (AAC) blockwork and lime sand brick, indoors and outdoors.
Why use it?
Its low density limits dead-load and material use on thin cosmetic repairs, it bonds to mineral substrates without priming, and it’s fire-rated to DIN 4102-2 Class F120.
How is it applied?
Mixed at 29-32 parts water per 100 parts powder in a forced-action mixer, hand-applied or wet-sprayed in 5-70 mm layers (up to 100 mm as reprofiling mortar), floated smooth, then cured about 3 days.
About MC-Bauchemie Nafufill LM
Most concrete-repair conversations centre on structural mortars – the R3/R4 grades that restore load-bearing capacity to a corroded column or a spalled beam soffit. Nafufill LM occupies a different, quieter niche. It’s an EN 1504-3 Class R1 mortar, which by definition is non-structural – meant for cosmetic and protective reprofiling, not carrying loads. What sets it apart is a genuinely low fresh-mortar density (1.43 kg/dm³) combined with a built-in bonding agent, so applicators can hand-apply or spray it directly onto a properly prepared, pre-wetted mineral substrate without a separate slurry coat, saving a work step on every balcony soffit, parapet or facade panel being reprofiled.
For Space Arc’s Delhi NCR and pan-India applicator base, the practical draw is threefold: it stays light enough to build up on vertical and overhead facade surfaces without excess dead load, it’s rated fire-resistant to DIN 4102-2 Class F120 and non-combustible per EN 13501-1 Class A1 – relevant wherever fire compliance gets scrutinised – and it’s one of the few repair mortars explicitly validated for porous lightweight concrete (AAC) and lime sand brick, both common in low-rise and infill construction. It is not a structural mortar, and it shouldn’t be specified as one; treat it exactly as its EN classification says – a cosmetic and protective reprofiling mortar for normal and lightweight substrates.
The technical insight
The number worth flagging to a site engineer is the strength profile: 14 N/mm² compressive and 3.7 N/mm² flexural at 28 days, from a fibre-reinforced, polymer-modified matrix with a maximum 1.2 mm grain size. That’s intentionally modest next to a structural R3 mortar’s 25-45 N/mm² – Nafufill LM trades ultimate strength for lower density, better crack resistance in thin sections, and reliable adhesion without priming. High water retention in the mix slows how fast the substrate can pull moisture from the fresh mortar, which is usually what causes shrinkage cracking in thin reprofiling layers on hot, wind-exposed facades. Working time also swings hard with temperature – 120 minutes at 8°C down to just 20 minutes at 30°C – so on a Delhi summer site, batch sizes need to match what the crew can place and finish within about 20 minutes.
Where it is used
- Partial and full-surface repair of facade render and RCC facade panels
- Balcony soffit, loggia and parapet reprofiling on normal and lightweight concrete
- Cosmetic patch repair of spalled/carbonated concrete not needing structural strength restoration
- Repair of porous lightweight/AAC (gas concrete) blockwork and panels
- Reprofiling on lime sand brick substrates
- Fire-rated repair work where DIN 4102 F120 or EN 13501-1 A1 documentation is required
- Wet-spray reprofiling of large facade areas via worm pump
Key advantages
- Bonds directly to prepared mineral substrates – no separate bonding slurry or primer coat needed
- Low fresh-mortar density (1.43 kg/dm³) reduces dead load and material consumption on thin repairs
- Fire-resistant to DIN 4102-2 Class F120; non-combustible per EN 13501-1 Class A1
- Fibre reinforcement improves cohesion and limits cracking in thin reprofiling layers
- Hand-applicable or wet-sprayable, suiting both small patches and large facade runs
- Buildable to 70 mm total thickness (100 mm as a reprofiling mortar) in staged layers
- Validated on gas concrete (AAC) and lime sand brick, not just normal-density RCC
Limitations & considerations
- R1-classified, so it’s non-structural – never use it to restore load-bearing capacity on a structural spall; that needs an R3/R4 mortar
- Working time falls to about 20 minutes at 30°C, so batch sizes must stay small on hot Indian summer sites
- Hand-mixing or split batching is explicitly disallowed – a forced-action or slow double mixer is required on site
- Substrate needs a minimum pull-off strength of ≥0.8 MPa before application, so weak concrete must be consolidated first
- Supplied only as a 20 kg factory-dried bag, with no ready-mixed or paste option
Selection & best practice
Pre-wet the substrate thoroughly – repeat on very porous concrete or AAC – and let standing water disappear before applying, since ponding thins the bond. Mix strictly in a forced-action or slow double mixer for 2-3 minutes, let the batch stand about 2 minutes, then re-mix before use. Lay a thin key coat first, build up fresh-in-fresh to the specified thickness, and protect the finished surface from direct sun and wind through the full 3-day cure.
Specifications
| System / Chemistry | One-component, polymer-modified, fibre-reinforced cementitious lightweight mortar with integrated bonding agent |
| EN 1504-3 Classification | Class R1 (Principle 3, methods 3.1 & 3.3) |
| Fire Rating | DIN 4102-2 Class F120 (fire-resistant); EN 13501-1 Class A1 (non-combustible) |
| Max. Grain Size | 1.2 mm |
| Mixing Ratio | 100 : 29-32 pbw (powder : water); approx. 5.8-6.4 L water per 20 kg bag |
| Compressive Strength | 3 N/mm² (24h) / 12 N/mm² (7d) / 14 N/mm² (28d) |
| Flexural Strength | 1.3 N/mm² (24h) / 2.8 N/mm² (7d) / 3.7 N/mm² (28d) |
| Layer Thickness | 5 mm min. per pass; 70 mm max. total; up to 100 mm as a reprofiling mortar |
| Consumption & Pack Size | Approx. 1.12 kg/m² per mm thickness (factory-dried mortar); supplied in 20 kg bags |
Industry use cases
Residential facade retrofit, Delhi NCR
Reprofiling spalled RCC balcony soffits and parapets on ageing apartment blocks ahead of repainting or texture finishing.
AAC block construction
Patch repair of chipped or damaged lightweight block panels on low-rise and infill projects.
Fire-rated building envelopes
Facade and attic repair where fire consultants require DIN 4102 fire-resistance documentation.
Heritage / lime sand brick structures
Cosmetic reprofiling where a lightweight, low-shrinkage mortar limits stress on older masonry.
Institutional facade maintenance
Wet-spray reprofiling over large balcony and loggia surfaces on schools, hospitals and offices.
Frequently asked questions
Is Nafufill LM strong enough for structural concrete repair?
Can it be sprayed, or only hand-applied?
How thick a layer can I apply in one pass?
Does it need a primer before application?
What’s the pack size and coverage?
Is it suitable for AAC or gas concrete blockwork?
How we position MC-Bauchemie Nafufill LM
Nafufill LM sits within MC-Bauchemie’s broader Nafufill concrete-repair mortar family, which spans this lightweight R1 grade up to structural R2-R4 mortars for load-bearing spall repair; Space Arc’s technical team can help match the right grade to the actual damage class rather than defaulting to one product. Fosroc’s Renderoc range covers similar concrete-repair ground in India, but its comparable products – such as Renderoc LA, a pourable micro-concrete for deep, congested repairs – target a different application method rather than hand/spray-applied lightweight reprofiling. Specifiers weighing the two brands should match by application method and EN/IS class first, not by brand alone.
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