About MC-Bauchemie Nafufill SBR

Nafufill SBR is MC-Bauchemie’s liquid SBR latex — a milky-white, saponification-resistant styrene-butadiene rubber dispersion that gets gauged into cement mortar rather than used as a paint-on membrane. On its own it looks unremarkable: a drum of white liquid with a density of about 1.01 kg/dm³. Gauged into a cement slurry or repair mortar, though, it changes how the hardened material behaves — the latex particles coalesce as the mix cures, forming a continuous polymer film that laces through the cement matrix, pulls down the modulus of elasticity, and gives the mortar enough flex to absorb shrinkage and thermal movement without hairline cracking at the bond line.

For a site engineer, that translates into three practical jobs: as a bond coat brushed onto prepared concrete before a repair mortar goes on wet-on-wet; as the polymer component mixed directly into repair mortars, screeds and waterproof plaster; and as a bonding slurry for cold joints, tile beds or stone cladding where a mechanical, non-porous bond matters more than a coating system. It has been a fixture of MC-Bauchemie’s Indian range for years, precisely because SBR-modified mortar remains the most economical way to get real bond strength on RCC patch repair, terrace waterproofing and bridge rehabilitation — jobs where an epoxy system would price itself out of the BOQ. Space Arc stocks both pack sizes for that reason: it’s usually the first material a contractor reaches for on a patch-repair or waterproof-plaster job, ahead of anything more specialised.

The technical insight

The number worth remembering off the data sheet is the adhesive-strength curve: 2.2 N/mm² at 7 days, climbing to 2.5 N/mm² at 28 days and 3.7 N/mm² at 90 days — and in every case MC-Bauchemie’s testing records failure by fracture in the parent concrete, not at the bond line. That’s the real signature of a working SBR bond coat: the weak point moves back into the substrate itself, so a repair patch that eventually fails in service is failing because the surrounding concrete gave way, not because the interface let go. The compressive strength of the SBR-gauged mortar system (57 N/mm² at 28 days) and its flexural strength (11.0 N/mm²) both sit well ahead of a plain 1:3 cement-sand mix, which is why MC-Bauchemie can position Nafufill SBR as a genuine alternative to epoxy or polyester resin mortars on cost-sensitive repair work, rather than just a cheaper also-ran.

Where it is used

• Bond coat for structural concrete repair mortars on RCC columns, beams and slabs
• Bridge and civil-engineering rehabilitation — patching decks, piers and abutments
• Cold-joint treatment between old and new concrete pours
• Bonding slurry beneath fresh cement screeds or toppings over hardened base slabs
• Repair-cum-waterproof plaster on terraces, sunken slabs and wet areas
• Fine cosmetic mortar for filling surface blowholes and honeycombing (with Nafuquick powder)
• Bonding hard-burnt brick, natural stone and tile to cementitious substrates
• Precast concrete element repair — patching chipped edges and damaged corners

Key advantages

• Adhesion is strong enough that MC-Bauchemie’s own tension tests fail in the parent concrete, not at the bond line
• Raises compressive and flexural strength of repair mortar well above an unmodified 1:3 mix
• Lowers permeability and chloride ingress, useful on reinforced-concrete repairs near rebar
• Reduces the modulus of elasticity so patched mortar flexes with the substrate instead of cracking at the joint
• Non-toxic and mixable with potable water, no special handling beyond standard site PPE
• Costs meaningfully less than an equivalent epoxy or polyester resin mortar system
• Workable to very thin bond-coat layers, useful where cover or clearance is tight
• Long track record on Indian sites — a material masons and site supervisors already know how to handle

Limitations & considerations

• It’s a bonding agent/additive, not a standalone waterproofing membrane — has to be part of a mortar or plaster system, never applied neat
• Shelf life is only 9 months from manufacture, so stock rotation matters on slow-moving sites
• Bond coat must be applied while still tacky and the repair mortar placed wet-on-wet — timing discipline is non-negotiable, not forgiving of a distracted crew
• A minimum substrate tensile strength of 1.5 N/mm² is specified, so weak or friable concrete needs to be cut back further before this will bond reliably
• The Indian TDS doesn’t cite IS/EN/ASTM compliance figures, so specifiers needing a certified standard reference on record should request project-specific documentation from MC-Bauchemie
• It restores cover and bond, not load-carrying capacity — it isn’t a substitute for structural strengthening where sections are under-designed

Selection & best practice

Specifications

Industry use cases

How we position MC-Bauchemie Nafufill SBR

Within MC-Bauchemie’s own range, Nafufill SBR sits alongside Nafufill SF (fine filler for cosmetic surface repair) and the Nafufill KM series of structural repair mortars, which are typically placed wet-on-wet over an SBR bond coat — on a real repair job the three often get specified together rather than any one standing alone. Where a project brief asks for a named alternative, Fosroc’s Nitobond SBR is the direct market equivalent.

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