Fosroc Nitobond SBR Latex
A single-component SBR latex bonding aid and gauging liquid that bridges old-to-new concrete and toughens site-batched mortars, screeds and waterproof renders.
What is it?
A ready-to-use, single-component modified styrene-butadiene rubber (SBR) emulsion that works both as a bonding bridge between old and new concrete and as a gauging liquid that improves the strength, adhesion and water resistance of cementitious mortars, screeds, renders and slurries.
Where is it used?
Concrete repair and rehabilitation, polymer-modified floor screeds and toppings, waterproof plasters and renders, bonding slurries for slip-bricks and tiles, and patch repairs to spalled or cracked RCC across buildings, water-retaining structures, industrial floors and infrastructure.
Why use it?
It delivers a durable cementitious bond without an epoxy, reduces permeability to chloride and aggressive agents, improves tensile and flexural performance to allow thin sections, and is hydrolysis-resistant so it suits both internal and external work.
How is it applied?
Used as a 1:1:3 SBR:water:cement slurry primer scrubbed onto a saturated-surface-dry substrate, and as a gauge liquid added to sand:cement mixes (typically 5-9 litres per 50 kg cement); the repair mortar is always applied wet-on-wet onto the still-wet primer.
About Fosroc Nitobond SBR Latex
Fosroc Nitobond SBR Latex is one of the most widely specified polymer bonding aids on Indian construction sites, and for good reason: it solves the single most common cause of repair failure, which is a weak bond between the existing substrate and the new mortar or screed laid over it. It is a modified styrene-butadiene rubber emulsion supplied as a ready-to-use white liquid. Site teams use it in two distinct but related roles. First, mixed with cement and water it forms a slurry bonding bridge that is scrubbed into the prepared substrate so the fresh repair material keys mechanically and chemically into the old concrete. Second, when a measured dose is added to the gauging water of a sand:cement mix, the polymer becomes part of the hardened matrix itself, lowering the water:cement ratio needed for workability, reducing permeability, and raising tensile and flexural strength. Because the polymer is resistant to hydrolysis, mortars gauged with Nitobond SBR Latex retain their improved properties even in damp and external exposure, unlike older PVA-type bonding agents that re-emulsify when wet. For contractors, consultants and procurement teams in India, this combination of a single, economical liquid that both primes and modifies makes it a practical default for routine concrete repair, screeding and waterproof rendering. Space Arc Engineering supplies genuine Fosroc Nitobond SBR Latex with batch traceability and on-site application support across Delhi NCR and pan-India.
The technical insight
The performance of Nitobond SBR Latex comes from two mechanisms working together. As a bonding slurry, the latex film bridges the interface and, because it stays cohesive while wet, the repair mortar must be placed wet-on-wet before the primer skins over, otherwise the bond is lost and the primer has to be removed and reapplied. As a mortar modifier the latex coalesces within the cement paste as it cures, which lets the mix be placed at a lower water:cement ratio (Fosroc’s India data compares a control at W/C 0.45 against a Nitobond SBR mix at W/C 0.35) while still being workable. Lower free water plus polymer reinforcement is what drives the measured gains in flexural and tensile strength and the reduction in permeability, including resistance to chloride ingress that protects embedded reinforcement. Fosroc’s published BS 6319 results for a 1:3 cement:sand mortar dosed at 5 litres per 50 kg cement show 28-day compressive strength rising from 22.0 to 24.0 N/mm2, tensile from 2.5 to 3.5 N/mm2 and flexural from 5.0 to 6.5 N/mm2 versus the unmodified control; higher dosages with further water reduction push these figures higher. A practical point often missed on site: the modified mortar is still a cementitious material, so it must be cured immediately and properly (Fosroc recommends Concure WB) and protected from frost and moving water until set.
Where it is used
- Slurry bonding bridge between hardened (old) concrete and freshly applied repair mortar, screed or render
- Polymer-modified floor screeds and toppings requiring thin sections and improved abrasion and crack resistance
- Patch repair of worn, spalled, honeycombed or chloride-damaged reinforced concrete
- Repair of large cracks and reinstatement around exposed, cleaned reinforcement
- Waterproof plasters and renders for masonry, including external and damp-exposed walls
- Bonding mortar and gauging liquid for fixing slip-bricks, ceramic tiles and stone cladding
- Cementitious bonding slurries and waterproof slurry coats for tanks, sumps and wet areas
Key advantages
- Single-component liquid that is simply gauged as required – no two-part mixing or batching of base and hardener
- Hydrolysis-resistant, so the improved properties survive damp and external exposure where PVA bonding agents fail
- Excellent bond to concrete, masonry, stonework, plaster and blockwork
- Reduces permeability and improves resistance to chloride ingress, helping protect embedded steel
- Improves tensile and flexural strength, allowing thinner, more durable applications
- Contains no chloride admixtures and is non-flammable, simplifying storage and handling
- Economical compared with epoxy bonding agents for routine, non-aggressive repair work
- Works as both a bonding primer and an integral mortar/screed modifier from the same drum
Limitations & considerations
- Bonding slurry must be applied wet-on-wet; if the primer dries before the mortar is placed it must be removed and the area re-primed
- Not a structural epoxy bonding agent – where a permanent moisture/vapour barrier or a substrate that stays continuously damp is involved, an epoxy such as Nitobond EP is specified instead
- Minimum application temperature is 10 degrees C; should not be applied when temperature is around 5 degrees C and falling
- Must be protected from frost in storage and from moving water and heavy rainfall before final set, or surface scour can occur
- Cured mortars are cementitious and require immediate, proper curing – the latex does not remove the need for a curing compound
- It is a bonding aid and modifier, not a standalone waterproofing membrane or a cosmetic finish coat
- 12-month shelf life and properties can be reduced if stored at high temperature or humidity
Selection & best practice
Prepare a clean, sound, mechanically keyed substrate free of dust, laitance, oil and loose material, then saturate it with clean water and remove standing excess to a saturated-surface-dry condition. Prime exposed reinforcement with a zinc-rich primer (e.g. Nitozinc/Nitoprime Zincrich) before proceeding. Mix the bonding slurry at 1 volume Nitobond SBR Latex to 1 volume clean water to 3 volumes fresh cement, blending the cement slowly into the pre-mixed liquids and stirring frequently to avoid settlement; scrub it well into the surface without puddling. Apply the repair mortar, screed or render wet-on-wet onto the still-wet slurry, working a thin layer in first and then building up. Keep added water in gauged mixes to the minimum needed for workability, allow for the moisture in site sand, do not retemper after initial set, cure immediately with Concure WB and protect from frost, moving water and rain until set.
Specifications
| Product type | Modified styrene-butadiene rubber (SBR) emulsion – bonding aid & mortar/screed modifier |
| Form / appearance | Ready-to-use single-component white liquid |
| Specific gravity | 1.015 to 1.040 @ 27 degrees C |
| Chloride content | Contains no chloride admixtures |
| Flammability | Non-flammable |
| Bonding slurry mix ratio | 1 volume SBR : 1 volume clean water : 3 volumes fresh cement (by volume) |
| Typical mortar dosage | 5 to 9 litres Nitobond SBR Latex per 50 kg cement (India mix designs) |
| Slurry primer coverage | Approx. 4 to 5 m2 per litre (varies with substrate porosity) |
| Compressive strength (28 day, BS 6319) | 24.0 N/mm2 modified vs 22.0 N/mm2 control (1:3 mortar, 5 L/50 kg cement) |
| Tensile strength (28 day, BS 6319) | 3.5 N/mm2 modified vs 2.5 N/mm2 control |
| Flexural strength (28 day, BS 6319) | 6.5 N/mm2 modified vs 5.0 N/mm2 control |
| Recommended section thickness | Repair/render approx. 8 to 30 mm; screeds approx. 10 to 25 mm per layer |
| Minimum application temperature | 10 degrees C (do not apply at ~5 degrees C and falling) |
| Curing | Cure immediately with Concure WB curing compound; protect from frost |
| Standards / test method | Mechanical properties tested to BS 6319 |
| Pack sizes (India) | 1, 5 and 20 litre containers |
| Shelf life | 12 months in unopened containers in a dry store |
| Reference | Fosroc India TDS INDIA/2005/0923/B |
Industry use cases
Building repair & rehabilitation
Re-bonding patch repairs to spalled RCC columns, beams, chajjas and slab soffits where carbonation or chloride attack has exposed reinforcement, using the SBR slurry as the bonding bridge and a gauged repair mortar.
Industrial & warehouse flooring
Laying polymer-modified bonded screeds and toppings (with 3-6 mm granite chips) over existing slabs to restore level and abrasion resistance in factories, godowns and loading bays.
Water-retaining & wet-area structures
Bonding waterproof renders, plasters and slurry coats in tanks, sumps, toilet and bathroom sunken slabs and terrace repairs where low permeability and damp resistance matter.
Masonry & facade works
Producing weather-resistant external renders and plasters on brick and block masonry, and gauging bonding mortar for fixing slip-bricks, tiles and stone cladding.
Infrastructure maintenance
Routine non-structural concrete repairs on bridges, drains, retaining walls and precast elements where an economical, hydrolysis-resistant bonding aid is preferred over epoxy for accessible, well-prepared surfaces.
Frequently asked questions
What is Fosroc Nitobond SBR Latex used for?
What is the correct mixing ratio for the bonding slurry?
How much Nitobond SBR Latex do I add to a mortar mix, and what is the coverage?
Is Nitobond SBR Latex a waterproofing product?
How is it different from Nitobond EP?
What pack sizes are available and how should it be stored?
How we position Fosroc Nitobond SBR Latex
Within the Fosroc concrete repair system, Nitobond SBR Latex is the everyday, economical bonding aid and mortar modifier, and it pairs naturally with related Fosroc products: a zinc-rich reinforcement primer such as Nitozinc/Nitoprime Zincrich for cleaned steel, Renderoc-type pre-bagged repair mortars where a controlled, factory-batched repair is preferred over a site mix, Concure WB for curing the finished work, and Dekguard anti-carbonation coatings to protect the surrounding structure. Where the job demands more than a wet-on-wet SBR bond – for example a permanent moisture barrier, extended open time, or a substrate that stays continuously damp – the two-part epoxy Nitobond EP is the correct step up. Against the broader Indian market, Nitobond SBR Latex competes directly with Sika Latex / Sika Latex Power (Sika’s SBR bonding aid), MBS (MYK/MBCC) SBR latex products, Dr. Fixit Pidicrete URP (Pidilite’s SBR bonding agent and mortar admixture), and STP’s SBR latex range. These are broadly comparable styrene-butadiene products, so selection usually comes down to specification approval, local availability, technical support and price rather than fundamental chemistry. Space Arc Engineering, as an authorised Fosroc distributor and applicator, supplies genuine Nitobond SBR Latex with the matching Fosroc primers, mortars and curing compounds so the whole repair system is compatible and warrantable, backed by application guidance for sites across Delhi NCR and pan-India.
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