Fosroc Nitobond SBR 201
Single-component SBR latex bonding aid and polymer-modifier for concrete repair mortars, screeds, renders and waterproof slurries.
What is it?
A ready-to-use, single-component styrene-butadiene rubber (SBR) latex emulsion that acts both as a bonding bridge between old and new concrete and as a gauging additive that toughens and waterproofs site-batched cementitious mortars, screeds and renders.
Where is it used?
Concrete repair and rehabilitation works, floor screeds and toppings, waterproof renders and plasters, and bonding slurries for slip bricks, tiles and stone, across building, industrial, water-retaining and infrastructure projects.
Why use it?
It dramatically improves the bond of new cementitious material to existing concrete, raises tensile and flexural strength so thinner sections are possible, reduces permeability for waterproof repairs, and is economical and easy to gauge on site.
How is it applied?
Used two ways: brushed/scrubbed into a prepared, pre-wetted substrate as an SBR-cement slurry bonding coat, and added to the gauging water of the sand-cement repair mortar, screed or render, which is then trowel-applied onto the still-wet bond coat and cured.
About Fosroc Nitobond SBR 201
Fosroc Nitobond SBR 201 is a modified styrene-butadiene rubber (SBR) emulsion supplied as a ready-to-use white liquid that performs the dual role of a bonding agent and a polymer modifier for site-batched cementitious mortars, screeds, renders and slurries. It belongs to Fosroc’s well-established Nitobond family of bonding aids and is the economical, general-purpose grade within the numbered SBR range. Where the sibling Nitobond SBR 101 is positioned for laying ceramic, marble, granite and stone, the 201 grade is aimed squarely at concrete repair, floor toppings, waterproof renders and everyday polymer-modified mortar work where reliable adhesion and durability matter more than premium tile-fixing performance. Chemically it is an aqueous SBR latex that is resistant to hydrolysis, which is why it suits both internal and external use in permanent contact with damp, alkaline cementitious systems rather than re-emulsifying like cheaper PVA-based aids. When gauged into a sand-cement mix it leaves a flexible polymer film woven through the hardened matrix; this film is what carries the improved tensile and flexural behaviour, the lower permeability and the strong freeze-thaw and wet-environment durability that contractors expect from an SBR-modified repair. Because the cementitious mortar it modifies remains highly alkaline, repairs made with Nitobond SBR 201 continue to passivate and protect embedded reinforcement, which is central to its role in concrete rehabilitation. The product is single-component and simply gauged as required, so there is no resin-and-hardener metering, no short working window from a chemical reaction, and no specialist plant beyond a forced-action mixer. For Indian projects it is offered in convenient liquid packs and is a familiar specification line item for consultants and contractors handling structural repair, basement and terrace renders, bonded screeds and tile-bedding mortars.
The technical insight
The defining characteristic of Nitobond SBR 201 is that the same product does two structurally different jobs. As a slurry bond coat it is mixed at 1 volume SBR : 1 volume clean water : 3 volumes fresh cement and scrubbed into a saturated-surface-dry substrate; the new mortar must be placed onto this coat while it is still wet, because once the slurry skins over its bond is lost and it has to be ground off and reapplied. As a gauging additive it is added to the mix water of the sand-cement mortar to internally modify it. Fosroc’s published mechanical data, generated to BS 6319 at 28 days (air-cured) on a 3:1 sand:cement mortar dosed at roughly 4 litres SBR per 20 kg cement, report compressive strength of 62 MPa, tensile strength of 3.3 MPa, flexural strength of 9 MPa and slant-shear bond of 53 MPa – the slant-shear figure in particular quantifies why an SBR-modified repair stays monolithic with the parent concrete. The SBR film also cuts permeability, which is the mechanism behind its waterproof renders and its high freeze-thaw resistance. Two practical points govern site success: it is water-based, so it must not be exposed to moving water or heavy rain before final set or the surface will scour; and like all cementitious repairs the finished mortar must be properly cured (Concure curing compound or polythene sheeting) immediately after finishing, otherwise the polymer film cannot develop its full toughness.
Where it is used
- Bonding bridge (SBR-cement slurry) between old hardened concrete and fresh repair mortar, screed or topping
- Polymer-modifying additive for site-batched concrete repair mortars on horizontal, vertical and overhead surfaces
- Bonded and heavy-duty floor screeds and toppings requiring abrasion resistance and a strong bond to the base slab
- Waterproof renders, plasters and cementitious slurry coats for basements, water tanks, terraces and external walls
- Bonding mortars for fixing slip bricks, tiles, stone and architectural cladding units
- Repair of worn, damaged, spalled and carbonated concrete in beams, columns, slabs and soffits
- Patch repairs around exposed and primed reinforcement as part of a corrosion-repair system
Key advantages
- Excellent adhesion to concrete, masonry, stonework, plaster and blockwork, giving a near-monolithic repair (slant-shear bond ~53 MPa to BS 6319)
- Improved tensile and flexural strength allow thinner, lighter applications than unmodified mortar
- Single-component liquid – simply gauged as required, with no resin/hardener mixing or short pot life
- Reduces permeability to produce genuinely waterproof repairs, renders and toppings
- High resistance to freeze-thaw cycling and to damp, wet-service environments
- Resistant to hydrolysis, so it performs in permanently damp and alkaline conditions
- Contains no chloride admixtures, protecting embedded reinforcing steel
- Compatible with all common hydraulic (Portland) cements and improves mix cohesion and workability
- Economical general-purpose grade, well suited to high-volume repair and screeding work
Limitations & considerations
- Water-based emulsion – must not be exposed to moving water, heavy rainfall or immersion before the modified mortar has reached final set, or surface scour occurs
- The slurry bond coat must be overlaid while still wet; if it dries/skins it must be ground off and the area re-primed
- Not a structural adhesive on its own – it modifies and bonds cementitious mortars; it does not replace epoxy bonding agents where a true vapour/moisture barrier or structural epoxy bond is required (use Nitobond EP for permanently damp or barrier situations)
- Should not be applied when temperature is 5 degrees C and falling; cementitious cure slows and strength gain is impaired in cold conditions
- Performance depends entirely on correct substrate preparation (sound, clean, laitance-free, saturated-surface-dry) and on accurate gauging of SBR and water against the sand moisture content
- Modified mortar is cement-based and still requires immediate, proper curing; skipping curing forfeits the polymer benefit and risks shrinkage cracking
- Recommended minimum application thickness is about 6 mm – not suited to feather-edging
Selection & best practice
Always saw-cut and break out the repair area to at least 6-10 mm, remove all laitance, dust, oil and unsound concrete, and expose, clean and prime any corroded reinforcement (Nitoprime Zincrich) before bonding. Pre-soak the substrate to saturated-surface-dry, then scrub in the 1:1:3 (SBR:water:cement by volume) slurry bond coat, and crucially place the SBR-modified sand-cement mortar onto the bond coat while it is still wet – never let it dry. Use a forced-action mixer, dry-blend cement and sand for one minute, then add pre-mixed SBR and water and mix 3-5 minutes; keep added water to the minimum and adjust for the actual moisture in site-stored sand. Build vertical work to about 15 mm and horizontal to 40 mm per pass, scratch-key intermediate layers, and cure the finished surface immediately with a Fosroc Concure curing compound or polythene sheeting. Avoid placement in moving water, heavy rain or when temperatures are at or below 5 degrees C and falling.
Specifications
| Product type | Single-component modified styrene-butadiene rubber (SBR) latex emulsion |
| Function | Bonding agent (slurry bond coat) and polymer additive for cementitious mortars |
| Appearance / colour | Ready-to-use white liquid |
| Specific gravity | Approx. 1.03 |
| Chloride content | Nil – contains no chloride admixtures |
| Compressive strength (modified mortar, BS 6319, 28 days) | 62 MPa |
| Tensile strength (BS 6319, 28 days) | 3.3 MPa |
| Flexural strength (BS 6319, 28 days) | 9 MPa |
| Slant-shear bond strength (BS 6319, 28 days) | 53 MPa |
| Slurry bond-coat mix ratio (by volume) | 1 SBR : 1 clean water : 3 fresh cement |
| Typical mortar dosage | Approx. 4 litres SBR per 20 kg cement (mortar) / 10 litres per 50 kg cement |
| Coverage as slurry primer | Approx. 2 to 3 m2 per litre |
| Application thickness | 6 mm minimum; up to 40 mm horizontal, up to ~15 mm vertical per pass |
| Curing | Immediate cure with Concure compound or polythene sheeting (cementitious) |
| Pack sizes | 1 litre, 5 litre, 20 litre (200 litre drum also available) |
| Shelf life | 12 months in original sealed packaging in a cool, dry store (Indian distributors often cite up to 24 months); protect from frost |
Industry use cases
Structural concrete repair
Bonding and modifying patch-repair mortars for spalled, carbonated or corrosion-damaged beams, columns, slabs and soffits in buildings, bridges and industrial structures, with the SBR slurry ensuring the patch stays monolithic with the parent concrete.
Flooring and screeds
Bonded heavy-duty floor screeds and toppings in warehouses, factories and commercial floors where a strong bond to the base slab and improved abrasion and flexural performance are needed.
Waterproofing and basements
SBR-modified waterproof renders and slurry coats for basement walls, water tanks, sumps, terraces and external plaster where reduced permeability and damp resistance are critical.
Tiling, cladding and stone
Bonding mortars for fixing slip bricks, ceramic tiles, stone and architectural units to concrete and masonry backgrounds.
Infrastructure and water-retaining structures
Repair and rendering of canals, drains, RCC water structures and marine-adjacent concrete where freeze-thaw and wet-service durability are required.
General building and renovation
Improving cohesion, workability and adhesion of everyday site-batched mortars and renders during refurbishment, plastering and patching across Delhi NCR and pan-India projects.
Frequently asked questions
What is Fosroc Nitobond SBR 201 and what does it do?
How do I mix Nitobond SBR 201 as a bonding coat?
How much area does it cover?
Is Nitobond SBR 201 waterproof and can it be used in wet areas?
How is the 201 grade different from Nitobond SBR 101 and SBR 202?
What pack sizes and shelf life does it have?
How we position Fosroc Nitobond SBR 201
Within the Fosroc system, Nitobond SBR 201 is the value-engineered, high-volume SBR latex bonding aid: it pairs naturally with Nitoprime Zincrich for reinforcement priming, Fosroc Concure curing compounds for after-cure, and Renderoc/concrete-repair mortars where a site-batched SBR-modified mortar is being placed. Step up to Nitobond EP (epoxy) when a permanent moisture/vapour barrier or a true structural bond to a permanently damp substrate is required, or to the application-specific Nitobond SBR 101 (tiling/stone) and SBR 202 (floor toppings and repair) grades when the job is more specialised. Against the wider market, the closest credible alternatives Indian specifiers will recognise are Sika Latex / Sika Latex Power and SikaTop bonding systems, MYK Laticrete / MBS bonding latexes, Dr. Fixit Pidicrete URP, and STP (Shalimar) SBR-based bonding aids – all comparable SBR or acrylic-SBR bonding admixtures. Nitobond SBR 201 holds its position on the strength of Fosroc’s published BS 6319 performance data, its chloride-free formulation, its proven slant-shear bond and its strong distributor and technical-support network in India, making it a safe, widely-specified default for concrete repair, bonded screeds and waterproof renders where contractors want dependable adhesion at a sensible price.
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