Fosroc Renderoc SFBD
Low-density, fibre-reinforced wet-spray repair mortar for fast, high-build reinstatement of damaged reinforced concrete and masonry.
What is it?
A single-component, polymer- and fibre-modified, low-density cementitious repair mortar from Fosroc, formulated for high-build reinstatement of concrete and masonry by wet-spray or trowel and classified as EN 1504-3 Class R3.
Where is it used?
Reinstatement of spalled and carbonation- or chloride-damaged reinforced concrete on bridges, flyovers, water structures, marine and coastal RCC, parking decks, industrial plants and large facade repairs across India.
Why use it?
Its low density and fibre reinforcement allow exceptionally high build per pass with compensated shrinkage, while the wet-spray process makes large-area, overhead and vertical repairs fast and labour-efficient without shuttering.
How is it applied?
Mechanically prepare and saturate the substrate, prime exposed steel and apply a bonding aid, gauge the powder with clean water only, then wet-spray or trowel to the required thickness and cure.
About Fosroc Renderoc SFBD
Fosroc Renderoc SFBD is a factory-blended, single-component concrete repair mortar engineered for the permanent reinstatement of damaged reinforced concrete and masonry. It belongs to Fosroc’s well-established Renderoc family of patch-repair and reprofiling mortars, but is distinguished by a low-density formulation that is modified with both polymers and reinforcing fibres. This combination delivers a mortar with compensated (controlled) shrinkage, excellent thermal compatibility with the parent concrete, and high resistance to the ingress of carbon dioxide and chloride ions, which are the two principal drivers of reinforcement corrosion in Indian structures.
The “SFBD” mortar is supplied as a ready-blended powder that requires only the site addition of clean water to produce a cohesive, sag-resistant mortar. Its defining advantage is build height: because the matrix is low in density and fibre-toughened, it can be applied at substantial thickness in a single pass, particularly when placed by the wet-spray (gunite-style) process. This makes it especially suited to large-area reinstatement where trowel-by-trowel patching would be slow and uneconomical. It can equally be hand-applied by trowel for smaller, localised pockets, giving contractors flexibility on a single site.
For Space Arc Engineering’s clients across Delhi NCR and Pan-India, Renderoc SFBD fits the repair brief on infrastructure and industrial assets where concrete cover has been lost to carbonation, chloride attack, impact, or fire, and where exposed steel must be re-embedded in a dense, low-permeability, alkaline mortar that protects it for the long term. It conforms to the requirements of EN 1504-3, the European standard for structural and non-structural concrete repair products, at Class R3, making it appropriate for a broad band of structural and cosmetic reinstatement work. As an authorised Fosroc distributor, Space Arc supplies Renderoc SFBD together with the matching Fosroc primer, bonding and curing system so that the repair is specified and executed as a complete, warranty-friendly system rather than a single product in isolation.
The technical insight
The engineering logic of Renderoc SFBD rests on three coupled properties: low density, fibre reinforcement and compensated shrinkage. A lower fresh density (in the order of 1.75 kg/litre) reduces the self-weight of freshly placed material, which is precisely what lets the mortar be built up to large thicknesses on vertical and overhead surfaces without slumping or de-bonding before set. The dispersed fibres bridge micro-cracks during the plastic and early-hardening phases, controlling shrinkage-induced cracking and adding flexural toughness so the repair behaves more like the surrounding concrete under thermal and load cycling. The polymer modification improves adhesion to the saturated, prepared substrate and lowers permeability, which is the mechanism by which the mortar resists re-ingress of chlorides and CO2 and re-establishes a protective, high-pH environment around the reinforcement. Strength development is engineered to be early and reliable, with a 1-day compressive strength of not less than 10 MPa and a 28-day compressive strength of the order of 30 MPa at 20°C, consistent with the EN 1504-3 Class R3 envelope. The practical takeaway is that thermal expansion compatibility and dimensional stability matter as much as raw strength in a repair mortar: an over-strong, stiff patch that shrinks away from the substrate will fail at the bond line long before a correctly matched, fibre-toughened mortar like SFBD does.
Where it is used
- Reinstatement of spalled and delaminated cover concrete on bridges, flyovers and elevated corridors
- Repair of carbonation- and chloride-induced corrosion damage in coastal and marine RCC structures
- High-build patch repair of beams, columns, soffits and slab undersides
- Large-area facade and external wall reprofiling on multi-storey and industrial buildings
- Reinstatement of water-retaining and water-conveying structures such as tanks, channels and treatment plants
- Repair of fire-, impact- or freeze-damaged concrete on industrial and infrastructure assets
- Masonry reinstatement and rendering where a tough, low-shrinkage cementitious mortar is required
- Wet-spray reinstatement on parking decks, jetties and other extensive horizontal and vertical surfaces
Key advantages
- Low-density, fibre-modified matrix enables exceptionally high build in a single application
- Wet-spray capability makes large-area, overhead and vertical repairs fast and labour-efficient
- Compensated shrinkage minimises cracking and bond-line failure on large reprofiled areas
- Low permeability resists chloride and carbon dioxide ingress, protecting embedded steel
- Excellent thermal compatibility and adherence with the parent concrete
- Single-component, site-mixed with clean water only, reducing batching errors
- Conforms to EN 1504-3 Class R3 for structural and non-structural repair
- Can be either machine-sprayed or hand-trowelled, giving site flexibility
- Good early strength supports faster reopening of repaired elements
Limitations & considerations
- As a Class R3 (not R4) mortar, it is not the highest structural-strength option in the Renderoc range for heavily loaded structural members
- Wet-spray application requires suitable spray equipment, a trained operator and reduces effective yield versus hand application
- Performance depends heavily on correct substrate preparation, reinforcement priming and a compatible bonding aid
- Like all cementitious repairs it requires proper wet/membrane curing in India’s hot, windy conditions to avoid plastic-shrinkage cracking
- Not a decorative or fair-faced finish coat on its own; a fairing coat or protective coating is usually needed for appearance and durability
- Application and strength gain are temperature-sensitive; very high ambient temperatures shorten working time
- Maximum single-pass thickness differs by orientation (vertical, horizontal and overhead) and must be respected
Selection & best practice
Achieve a durable repair by treating Renderoc SFBD as one element of a full Fosroc repair system. Saw-cut the perimeter of the repair zone to a defined edge, break out all loose and contaminated concrete to sound substrate, and expose corroded steel fully around its circumference. Grit-blast or wire-brush the reinforcement to bright metal, then apply a Fosroc zinc-rich or alkaline primer (such as the Nitozinc / Renderoc system primer) before placing mortar. Pre-saturate the substrate to a saturated-surface-dry condition and apply the recommended bonding aid wet-on-wet. Gauge only with clean potable water to the specified consistency, mix mechanically, and place within the working time. Build to the orientation-specific thickness limits, compacting well against the bond coat, and key intermediate layers if multiple passes are needed. In Indian summer conditions, cure immediately and continuously with wet hessian or a compatible curing membrane for the recommended period, and protect from direct sun and drying wind. For aggressive or aesthetically critical environments, overcoat with a Fosroc fairing coat and an anti-carbonation or protective coating. Always work to the current product TDS and confirm pack-specific data with Space Arc’s technical team before specification.
Specifications
| Product type | Single-component, polymer- and fibre-modified, low-density cementitious repair mortar |
| Standard / classification | Conforms to EN 1504-3, Class R3 |
| 1-day compressive strength | Not less than 10 MPa (at 20°C) |
| 28-day compressive strength | Approx. 30 MPa (at 20°C) |
| Fresh (wet) density | Approx. 1.75 kg/litre |
| Application thickness – vertical | 6-50 mm |
| Application thickness – horizontal | 6-100 mm |
| Application thickness – overhead | 6-20 mm |
| Mixing | Site-mixed with clean water only (ready-blended powder) |
| Application method | Wet-spray process or hand trowel |
| Key performance | Compensated shrinkage; low permeability to CO2 and chloride; high thermal compatibility with concrete |
| Typical uses | Reinstatement of reinforced concrete and masonry, high-build and large-area repair |
Industry use cases
Bridges & Infrastructure
Wet-spray reinstatement of spalled soffits, beams and piers on highway flyovers and bridges where carbonation and chloride attack have caused cover loss and reinforcement corrosion.
Marine & Coastal RCC
High-build repair of chloride-damaged jetties, sea walls and coastal buildings, using the mortar’s low permeability to re-protect exposed steel in aggressive saline exposure.
Water & Wastewater
Reinstatement of water-retaining tanks, channels and treatment-plant concrete where a dense, low-shrinkage mortar is needed to restore cover and section.
Industrial Plants
Repair of fire-, impact- and chemically degraded concrete on columns, slabs and structures in factories, refineries and power assets, often over large areas by spray.
Commercial & High-Rise
Large-area facade and external-wall reprofiling and balcony/soffit repair on multi-storey buildings where shuttering-free, high-build patching saves time.
Parking & Decks
Reinstatement of corrosion-damaged parking decks and ramps, where wet-spray application speeds up extensive horizontal and vertical repairs.
Frequently asked questions
What is Fosroc Renderoc SFBD used for?
Is Renderoc SFBD a structural repair mortar?
How thick can Renderoc SFBD be applied in one pass?
Does Renderoc SFBD need a primer or bonding agent?
How is Renderoc SFBD different from Renderoc HB or Renderoc S?
Is Renderoc SFBD available in Delhi NCR and Pan-India?
How we position Fosroc Renderoc SFBD
Within Fosroc’s Renderoc concrete-repair range, Renderoc SFBD occupies the niche of low-density, fibre-modified, wet-sprayable high-build reinstatement, making it the natural choice for large-area, overhead and vertical repairs that would be slow by hand. Where the structural element is heavily loaded and demands maximum strength, an EN 1504-3 Class R4 mortar such as Renderoc HB or a flowing micro-concrete like Renderoc RG/LA may be more appropriate, and for fine fairing coats Renderoc FC is the complementary product; Space Arc helps clients select between these. Against competitor systems, Renderoc SFBD competes most directly with Sika’s MonoTop and SikaRep spray/repair mortars, MBS (Master Builders Solutions / MasterEmaco) repair mortars, Dr. Fixit Pidicrete and Fairmate repair mortars, and STP / other Indian repair mortar ranges. Its differentiators are the established Renderoc system ecosystem, the low-density fibre-toughened matrix tuned for high build, and the wet-spray productivity advantage on extensive jobs. Honestly, for very small, isolated patches a hand-applied mortar or a competitor’s pre-bagged patch product may be simpler and more economical, and where spray equipment is unavailable the wet-spray benefit is lost; the SFBD case is strongest on medium-to-large reinstatement programmes where build height, speed and durable steel protection together drive the specification.
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