Fosroc Renderoc TS
A thixotropic, sulphate-resistant cementitious repair mortar engineered for concrete in coastal zones, seaports and sulphate-bearing ground conditions.
What is it?
A single-component, thixotropic cementitious repair mortar from Fosroc that is specifically formulated to resist sulphate attack, used to reinstate damaged concrete cover by trowel or by wet/dry spray.
Where is it used?
Concrete structures exposed to sulphate-rich environments – coastal belts, ports and jetties, sea-water intake structures, sewage and effluent works, and foundations sitting in sulphate- or selenite-bearing soils and groundwater.
Why use it?
Ordinary OPC repair mortars degrade when attacked by sulphates; Renderoc TS combines sulphate resistance with compensated shrinkage, low permeability and strong bond, so the repaired patch survives in chemically hostile conditions rather than re-failing.
How is it applied?
The concrete is broken out to sound substrate, reinforcement is cleaned and primed, the surface is saturated to SSD, then the mixed mortar is trowel-applied or sprayed and built up in layers – overhead to 7-40 mm and vertically to 7-60 mm – before curing.
About Fosroc Renderoc TS
Fosroc Renderoc TS is a factory-blended, single-component repair mortar supplied as a dry powder that needs only the addition of clean water on site. It belongs to Fosroc’s Renderoc family of cementitious concrete-repair mortars, but TS is the grade engineered for one specific enemy: sulphate attack. The “TS” denotes its thixotropic, sulphate-resistant character. Once gauged with water it forms a cohesive, non-sag paste that can be worked overhead and on vertical faces without slumping, then cures to a dense, low-permeability mortar that knits firmly to the parent concrete.
The reason this grade exists is that large parts of India present aggressive ground and water chemistry. Along the Gujarat, Maharashtra, Tamil Nadu, Odisha and coastal Andhra belts, structures sit in sea water, saline groundwater and sulphate-bearing soils. Inland, gypsum-rich (selenite) soils and industrial effluent in pockets of Rajasthan, parts of the Indo-Gangetic plain and around chemical and sugar plants expose foundations and below-grade concrete to dissolved sulphates. When sulphate ions reach ordinary Portland-cement concrete they react to form expansive ettringite and gypsum, which crack and spall the cover. Patching such concrete with a normal repair mortar simply re-creates a sacrificial layer that fails again. Renderoc TS is designed so that the repair itself is sulphate-resistant.
Functionally, the product does four things at once. It is compactly graded and dense, giving it inherently low permeability and resistance to chemical ingress. It carries compensated-shrinkage technology, so even large reinstated areas can be repaired without the drying-shrinkage cracking that opens fresh paths for water and sulphates. It bonds strongly to a properly prepared substrate, and it incorporates additives that improve density and help screen out carbon dioxide and chloride ions – the two agents that drive carbonation and reinforcement corrosion. For structures where embedded steel is already at risk, Fosroc offers a closely related grade, Renderoc TS-IC, which adds an integral corrosion inhibitor to the same sulphate-resistant base.
For specifiers and contractors in Delhi NCR and across India, the appeal of Renderoc TS is that it pairs a single, well-understood Fosroc system with the durability logic that aggressive-exposure repair demands – rather than relying on a general-purpose mortar and hoping it holds.
The technical insight
The engineering heart of Renderoc TS is the interaction between its binder chemistry and its physical density. Sulphate durability is achieved at the binder level – the mortar is formulated to resist the formation of expansive ettringite and gypsum that destroys ordinary OPC-based repairs in sulphate environments. But chemistry alone is not enough; a porous mortar lets sulphate-laden water travel inward regardless of binder type. So the mix is gap-graded and additive-modified to a high packing density, reported at a fresh wet density of about 2.2 kg/l, which translates into low permeability and a tight pore structure. That same density is what restricts the inward diffusion of CO2 and chloride ions, the precursors of carbonation and pitting corrosion of reinforcement. The thixotropy is the application-side counterpart: the mortar is shear-thinning, flowing under the trowel or spray nozzle yet standing firm once placed, which is what allows substantial overhead (to 40 mm) and vertical (to 60 mm) build-ups in a single operation without sagging. Compensated shrinkage closes the loop by keeping the cured matrix crack-free, because a hairline shrinkage crack would short-circuit all of the above by giving sulphates a direct route to the steel.
Where it is used
- Repair of spalled and sulphate-damaged concrete in coastal and marine structures – jetties, quay walls, sea-water intake and outfall structures
- Reinstatement of concrete cover on port, harbour and dock structures exposed to splash, tidal and saline conditions
- Repair of foundations, pile caps, plinths and below-grade concrete sitting in sulphate-bearing or selenite (gypsum-rich) soils and groundwater
- Rehabilitation of sewage treatment works, effluent channels and water-handling structures subject to sulphate exposure
- Patch repair of beams, columns and soffits in industrial plants (chemical, fertiliser, sugar) where sulphate-laden water or process spillage attacks concrete
- Overhead and vertical repairs where a non-sag, build-up mortar is required by trowel or by wet/dry spray
Key advantages
- Sulphate-resistant by formulation, so the repair survives in marine, saline-soil and effluent environments where ordinary mortars degrade
- Compensated shrinkage allows large reinstated areas to be repaired without drying-shrinkage cracking
- High compactness and low permeability give strong resistance to chemical attack and to CO2 and chloride-ion ingress
- Thixotropic, non-sag consistency permits substantial overhead and vertical build – up to 7-40 mm overhead and 7-60 mm vertically
- Excellent bond to a properly prepared concrete substrate
- Versatile placement – can be trowel-applied or applied by wet or dry spray process for large-scale work
- Single-component, site-batched with clean water only, simplifying logistics and quality control
- Companion grade (Renderoc TS-IC) available with integral corrosion inhibitor for structures with at-risk reinforcement
Limitations & considerations
- Purpose-built for sulphate-exposure repair; for general non-aggressive concrete repair a standard Renderoc grade (e.g. GP, HB, S) may be more economical
- Requires correct substrate preparation – breaking out to sound concrete, cleaning and priming reinforcement, and bringing the surface to a saturated surface-dry (SSD) condition – or bond and durability suffer
- Maximum build is limited per layer (about 40 mm overhead, 60 mm vertical); deeper or larger-volume reinstatement may need build-up in layers or a flowable micro-concrete grade
- Proper curing is essential; inadequate curing in India’s hot, dry or windy conditions can compromise strength and the crack-free, low-permeability matrix
- Where steel corrosion is the primary driver, a corrosion-inhibiting grade (Renderoc TS-IC) or a dedicated anti-corrosion primer should be considered alongside or instead of TS
- Detailed numeric properties (compressive/flexural strength, EN 1504-3 R-class) vary by region and batch and should be confirmed against the current local TDS before specification
Selection & best practice
Treat Renderoc TS as part of a repair system, not a stand-alone patch. First diagnose the exposure – confirm by soil/water testing that sulphates (and any chlorides) are genuinely the aggressor, because that is what justifies this grade over a general-purpose Renderoc. Break out all unsound, carbonated or contaminated concrete back to a sound substrate with a square-edged perimeter (avoid feather-edging), expose corroded reinforcement fully around its circumference, and clean the steel to bright metal before priming it – use Fosroc’s zinc-rich/anti-corrosion primer (Nitoprime Zincrich) or pair with the TS-IC corrosion-inhibiting grade where steel is compromised. Bring the prepared concrete to a saturated surface-dry condition, apply the recommended bonding primer, then place the mortar firmly into the repair, building overhead and vertical work within the stated layer limits. Compact and finish, then cure diligently – in Indian summer and coastal wind, wet-curing or a curing membrane (Concure) is non-negotiable to prevent plastic and drying-shrinkage cracking. Always work to the current Fosroc TDS for the specific country/region and obtain material from an authorised distributor such as Space Arc Engineering to ensure genuine, in-date product.
Specifications
| Product type | Single-component, thixotropic cementitious repair mortar |
| Primary characteristic | Sulphate-resistant (formulated for sulphate-bearing environments) |
| Shrinkage | Compensated shrinkage (large areas repaired with no shrinkage) |
| Fresh (wet) density | Approx. 2.2 kg/l |
| Application thickness – overhead | 7-40 mm |
| Application thickness – vertical | 7-60 mm |
| Application methods | Trowel, or wet / dry spray process |
| Permeability | Low; additives provide protection against CO2 and chloride-ion ingress |
| Related grade | Renderoc TS-IC (same base + integral corrosion inhibitor) |
| Mixing | Single-component powder gauged with clean water on site |
Industry use cases
Ports & Marine
Reinstating spalled cover on jetties, quay walls and sea-water intake structures along India’s coastal belts, where tidal and saline exposure carries dissolved sulphates and chlorides into the concrete.
Water & Wastewater
Repairing sulphate-attacked concrete in sewage treatment works, effluent channels and water-handling structures, where the repair mortar itself must resist ongoing chemical exposure.
Infrastructure Foundations
Restoring foundations, pile caps and below-grade concrete sitting in sulphate- or gypsum-bearing (selenite) soils and groundwater, common in parts of Gujarat, Rajasthan and the Indo-Gangetic plain.
Industrial Plants
Patch-repairing beams, columns and soffits in chemical, fertiliser and sugar plants where sulphate-laden process water and spillage degrade ordinary concrete and ordinary repairs.
Frequently asked questions
What makes Renderoc TS different from other Renderoc repair mortars?
Where in India is Renderoc TS most relevant?
How thick can Renderoc TS be applied in one pass?
Can it be sprayed, or only trowel-applied?
What is the difference between Renderoc TS and Renderoc TS-IC?
How important is surface preparation and curing?
How we position Fosroc Renderoc TS
Renderoc TS occupies the specialist, sulphate-resistant slot within Fosroc’s concrete-repair range. Within that range it sits alongside general-purpose and high-build grades – Renderoc GP, Renderoc HB, Renderoc S and the flowable micro-concretes – which are the right choice for non-aggressive repairs; you step up to TS specifically when the exposure is sulphate-driven. Its closest sibling is Renderoc TS-IC, the same sulphate-resistant base with an integral corrosion inhibitor for structures with compromised reinforcement; choose TS for sound-steel sulphate exposure and TS-IC where corrosion is active. A typical TS repair is also specified as part of a Fosroc system – Nitoprime Zincrich on the steel and Concure or Nitobond for priming/curing. Against competitor systems, the practical equivalents are Sika’s MonoTop/Sika sulphate-resistant repair mortars, MBS (MYK/BASF-lineage) Concresive/EMACO-type repair mortars, Dr. Fixit’s Krishna/repair-mortar range and STP’s repair systems; many of these offer EN 1504-3 R3/R4 mortars and a sulphate-resistant or marine-grade option in the same niche. Honest positioning: Renderoc TS is a strong, well-supported choice where sulphate exposure is the governing durability risk, but it is not a do-everything mortar – match the grade to the diagnosed aggressor and the steel condition, and verify current numeric specs and EN 1504-3 R-class on the local TDS. Space Arc Engineering supplies genuine Fosroc Renderoc TS and the supporting system products, with technical guidance, across Delhi NCR and Pan-India.
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