About Fosroc Renderoc TGXtra

Fosroc Renderoc TGXtra is a trowel-grade, shrinkage-controlled cementitious repair mortar from Fosroc’s well-established Renderoc concrete-repair family. It is engineered for hand application to areas of deteriorated or damaged concrete where light to medium load-bearing capacity must be restored. The “TG” denotes Trowel Grade and the “Xtra” designation marks Fosroc’s upgraded formulation built around what the company calls Dimensional Stability Technology — a system that holds the dimensions of the cured repair stable as it dries, the single biggest cause of failure in conventional sand-cement patching.

Supplied as a factory-blended dry powder in 25 kg bags, the product is a graded blend of cements, selected aggregates and performance additives. On site it needs nothing more than the addition of clean water to produce a cohesive, low-slump mortar that can be worked onto vertical faces and overhead soffits without falling away. One 25 kg bag yields approximately 15.8 litres of mixed mortar, which makes job estimating straightforward — divide the void volume in litres by 15.8 to arrive at the number of bags.

In an Indian context, Renderoc TGXtra answers a very common problem. Reinforced-concrete structures across Delhi NCR and the wider country suffer cover-concrete spalling driven by carbonation, chloride ingress near coasts, monsoon-driven wet-dry cycling and the corrosion of reinforcement that follows. Once steel rusts and bursts the cover, the exposed area has to be cut back, the bar cleaned and protected, and the profile reinstated with a repair mortar that bonds to old concrete, resists further water ingress and does not crack as it shrinks. TGXtra is positioned squarely at that medium-scale “covercrete restoration” duty — bigger than a smoothing skim, smaller than a structural micro-concrete pour.

As an authorised Fosroc distributor serving Delhi NCR and Pan-India, Space Arc Engineering supplies genuine Renderoc TGXtra together with its companion Fosroc primers and curing products so that the complete repair system is specified and sourced from one accountable channel.

The technical insight

The defining technical feature of Renderoc TGXtra is shrinkage management. Ordinary cementitious mortars lose volume as water leaves the matrix during drying; on a restrained repair patch this manifests as micro-cracking, debonding at the perimeter and loss of the protective barrier. Fosroc’s published data shows TGXtra holding drying shrinkage to under 300 microstrain at 7 days and under 500 microstrain at 28 days (tested to ASTM C157-93). Keeping movement this low is what allows the material to be feathered into the host concrete and remain monolithic.

The mortar develops practical structural performance for its class: compressive strength of around 35 N/mm2 at 7 days rising to 40 N/mm2 at 28 days, with flexural strength in excess of 6.5 N/mm2 at 28 days. These figures sit comfortably above typical C30-C40 host concrete, so the repair is not a weak link, yet the modulus is matched closely enough to the parent concrete to avoid the stress concentrations that destroy over-stiff repairs. Durability is reinforced by a dense, low-permeability matrix verified for low permeability under DIN 1048 Pt. 5 and low water absorption under BS 1881 Pt. 122 — the same low-permeability character that resists the chloride and carbon-dioxide ingress responsible for the original corrosion. The trowel-grade rheology is the practical enabler: high cohesion and controlled slump let an applicator build 50 mm in a single pass overhead without sagging.

Where it is used

• Reinstating spalled cover concrete on RCC beams, columns and slab soffits
• Vertical and overhead patch repairs where formwork cannot practically be erected
• Restoring honeycombed concrete and blowholes left by poor compaction
• Filling voids and pockets greater than 10 mm deep in concrete and masonry
• General concrete and masonry repairs in buildings, water-retaining and marine structures
• Repairs to corrosion-damaged areas after reinforcement has been cleaned and primed
• Facade and parapet repairs on multi-storey and heritage structures
• Patch repairs to bridge soffits, piers, jetties and industrial RCC frames

Key advantages

• Dimensional Stability Technology controls drying shrinkage, virtually eliminating shrinkage cracking in the repair
• Trowel-grade consistency allows 10-50 mm builds on vertical and overhead faces in a single pass without slumping
• Develops 40 N/mm2 compressive strength at 28 days, comfortably matching typical host concrete
• Dense, low-permeability matrix improves long-term durability and resistance to further chloride and carbonation ingress
• Supplied as a single-component pre-blended powder needing only site water — no batching of cement and sand, consistent quality
• Predictable yield of 15.8 litres per 25 kg bag simplifies material estimation
• Good compatibility with the parent concrete, reducing interface stress and debonding
• Non-flammable and straightforward to apply by trowel with standard site labour

Limitations & considerations

• Designed for light to medium load-bearing repairs — for heavily loaded or large-section structural reinstatement, micro-concrete grades such as Renderoc HSXtra are more appropriate
• Hand/trowel application limits per-pass thickness (about 50 mm vertical/overhead, up to 100 mm in horizontal pockets); deeper builds need multiple passes
• Should not be applied when ambient temperature is below 5 degrees C and falling
• Must not be part-mixed or part-bags used, which can be wasteful on very small repairs
• Must not be exposed to running water during application or before final set, and water ponding is not recommended for curing
• Exposed reinforcement and the substrate require correct preparation and priming with companion Fosroc products — the mortar is not a standalone corrosion treatment
• Shelf life is 12 months in dry storage but can fall to as little as 4 months in high humidity or heat, a real consideration in Indian monsoon and summer conditions

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Renderoc TGXtra

Within the Fosroc Renderoc range, TGXtra is the trowel-grade, medium-duty choice. Step up to Renderoc HSXtra (a high-strength micro-concrete / hand-placed structural grade) where heavier loads, larger sections or higher strengths are required, or to a flowable Renderoc micro-concrete where formwork can be erected and pours are large. For thin re-profiling or fairing coats over sound concrete, a lighter Renderoc skim/fairing grade is more economical than TGXtra. The repair should always be paired with the correct Fosroc rebar primer, bonding primer and a Concure curing membrane. Against competitor systems, Renderoc TGXtra is directly comparable to Sika MonoTop and Sikadur-based patch mortars, MBS (MYK / BASF-lineage) Emaco / MasterEmaco repair mortars, Dr. Fixit Krack-X / repair mortar grades, and STP (Sika-STP) repair products. Each major brand offers a shrinkage-controlled vertical-and-overhead repair mortar in this medium-duty class; selection in India usually comes down to verified strength and shrinkage data, local availability, applicator familiarity and project specification. Space Arc Engineering’s value is in matching the right grade to the defect, supplying genuine Fosroc material and the full compatible system rather than a single tub of mortar.

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