Fosroc Renderoc SM
Flowing, non-shrink micro-concrete that reinstates large damaged floor slabs in a single pour up to 100 mm thick — high early strength, low permeability, and no cracking on hardening.
What is it?
A single-component, pre-packed flowing micro-concrete from Portland cement, graded filler, shrinkage-compensating agents and special additives — site-mixed with only clean water to reinstate damaged concrete floors.
Where is it used?
Large damaged horizontal slabs: warehouse and factory floors, production-area slabs, parking decks and ramps, loading bays — anywhere a flowable, self-levelling structural repair is needed.
Why use it?
It pours and flows into deep sections up to 100 mm in one lift, compensates for shrinkage so the repair does not crack on hardening, and gains 32 N/mm² in 24 hours so floors return to service fast.
How is it applied?
Cut back to sound concrete, prime with Nitobond AR or Nitobond SBR, mix 25 kg with 3.0 L clean water to a flowable grout, pour into the formed/contained area, then cure with Concure membrane or wet hessian.
About Fosroc Renderoc SM
Fosroc Renderoc SM is a high-strength, non-shrink cementitious flowing micro-concrete engineered specifically for the reinstatement of large, damaged concrete floor areas. Unlike the trowel-applied repair mortars in the Renderoc family (such as Renderoc HB or Renderoc S), Renderoc SM is formulated to a flowable consistency so it can be poured and self-levelled into deep horizontal repairs in a single operation. The product arrives on site as a pre-packed dry powder — a precisely controlled blend of Portland cement, graded mineral filler, shrinkage-compensating agents and performance additives — that requires nothing more than the on-site addition of clean water. This factory-controlled formulation removes the batching variability that plagues site-mixed concrete repairs and gives the applicator a consistent, repeatable result across every bag.
The product is purpose-built for situations where a repair must carry load again quickly. Warehouse floors, production-area slabs, parking structures, loading docks and industrial pavements all suffer from impact damage, delamination, spalling, abrasion wear and chemical attack that leave deep, irregular voids. Patching these with ordinary concrete invites plastic and drying shrinkage cracking, debonding and slow strength gain. Renderoc SM addresses each of these failure modes: it flows under its own weight to fill complex profiles without honeycombing, it contains no chloride admixture, its shrinkage-compensating chemistry counters the volume loss that causes hardened-state cracking, and its dense, low-permeability matrix resists the ingress of carbon dioxide and chlorides that drive reinforcement corrosion.
For Indian infrastructure and industrial owners, this combination is particularly valuable. Floors in logistics parks, manufacturing units and multi-level car parks across Delhi NCR and the wider country are subject to heavy wheeled traffic, point loading from racking and forklifts, and aggressive operating environments. Renderoc SM allows a contractor to take a deep, full-depth slab repair from preparation to reopening in a compressed window — the material reaches roughly 32 N/mm² within 24 hours at 30°C — minimising the downtime that makes structural repair so expensive for an operating facility. As an authorised Fosroc distributor, Space Arc Engineering supplies genuine Renderoc SM together with the matching ancillaries — Nitobond bonding primers and Concure curing membranes — so the full repair system is specified and sourced from one accountable partner.
The technical insight
Renderoc SM’s defining characteristic is that it is a micro-concrete, not a mortar — its graded filler extends the binder so a single pour can fill sections up to 100 mm deep without the heat-of-hydration and shrinkage problems of a neat repair mortar at that thickness. The published data is generated at a water:powder ratio of 0.12 and 30°C, conditions that mirror Indian site temperatures. At that mix it develops 32 N/mm² at 1 day, 45 N/mm² at 7 days and 55 N/mm² at 28 days in compression (ASTM C942:1999), with a flexural strength of 7.0 N/mm² at 28 days (BS 4551:1980). The critical durability figures are the drying-shrinkage values — under 400 microstrain at 7 days and under 700 microstrain at 28 days — which, combined with the in-built shrinkage-compensating expansion, are what keep the hardened repair monolithic and crack-free. A Young’s modulus of 28 kN/mm² (ASTM 469-83) and a fresh wet density of around 2300 kg/m³ confirm it behaves as a genuine structural concrete, so the repair shares load with the surrounding slab rather than acting as a stiff or weak inclusion. Initial set is about 5.5 hours and final set about 6.5 hours (ASTM C953:1997), giving a realistic placing window before the material stiffens. The flowable mix uses 3.0 litres of clean water per 25 kg bag; over-watering to ease flow is the single most common field error and directly compromises strength, density and shrinkage performance.
Where it is used
- Reinstatement of large, deep damaged areas in warehouse and distribution-centre floor slabs
- Repair of production-area and factory floors subject to heavy plant and forklift traffic
- Full-depth repair of parking-structure decks, ramps and bay slabs
- Restoration of loading docks, dock levellers and impact-damaged slab edges
- Filling of deep voids, delaminations and spalls in industrial concrete pavements
- Floor-level structural repairs where a flowable, self-levelling micro-concrete is preferred over trowelled mortar
- Pour-and-place repairs up to 100 mm thick in a single lift without honeycombing
Key advantages
- High early strength — about 32 N/mm² at 24 hours — allows floors to be returned to service quickly
- Flowable micro-concrete self-levels into deep, irregular profiles up to 100 mm in one pour
- Shrinkage-compensating chemistry reduces and eliminates cracking in the hardened state
- Low permeability gives excellent resistance to carbon dioxide and chloride ingress, protecting embedded steel
- Contains no chloride admixture, so it does not introduce corrosion risk
- Pre-packed, single-component powder — only clean water added on site, ensuring batch-to-batch consistency
- Genuinely structural: 55 N/mm² at 28 days with a 28 kN/mm² modulus compatible with parent concrete
- Part of the wider Fosroc Renderoc repair system with matched Nitobond primers and Concure curing membranes
Limitations & considerations
- Designed for horizontal floor repairs — its flowable consistency is unsuitable for vertical or overhead work (use trowel-grade Renderoc HB / Renderoc S instead)
- Maximum 100 mm in a single section; larger or deeper sections require addition of approved aggregate or multiple lifts
- Mix water is fixed at 3.0 L per 25 kg bag — adding more water to improve flow seriously reduces strength, density and shrinkage performance
- Requires a properly cut-back, sound, primed substrate (Nitobond AR / SBR); placing on laitance or loose material causes debonding
- Needs disciplined curing (Concure membrane, water or wet hessian) — inadequate curing in hot, dry Indian conditions risks surface cracking
- Alkaline material; gloves, goggles and a dust mask are required during mixing and placing
- 12-month shelf life in sealed bags in dry storage — high temperature and humidity shorten it
- Requires a high-shear mechanical mixer (around 400 rpm) for proper dispersion; hand-mixing is not recommended
Selection & best practice
Treat Renderoc SM as a system, not just a bag of powder. First cut the defective concrete back to a sound, mechanically prepared base — remove all laitance, oil, grease and loosely adherent material, and where reinforcement is exposed, clean and prime it appropriately. Saturate the substrate to a saturated-surface-dry condition and apply Nitobond AR or Nitobond SBR as a bonding primer, placing the Renderoc SM while the primer is still tacky. Use a high-shear mechanical mixer with a paddle (around 400 rpm): add roughly 90% of the 3.0 L of water first, add the full 25 kg of powder, mix about 2 minutes to break up lumps, then add the remaining gauge water and mix for at least a further 3 minutes until homogeneous — never exceed 3.0 L per bag. Pour continuously into a contained or formed area so the material flows and self-levels without cold joints, and plan the operation as one continuous pour with enough mixers and labour. Immediately on completion, cure thoroughly with Concure curing membrane, continuous water spray or wet hessian — this is non-negotiable in Delhi NCR summer heat where rapid surface drying otherwise causes shrinkage cracking. For sections deeper than 100 mm, batch in approved graded aggregate as advised by Fosroc rather than over-thickening a single lift.
Specifications
| Material type | Single-component flowing micro-concrete (Portland cement, graded filler, shrinkage-compensating agents, additives) |
| Compressive strength (ASTM C942:1999) | 32 N/mm² @ 1 day; 45 N/mm² @ 7 days; 55 N/mm² @ 28 days |
| Flexural strength (BS 4551:1980) | 7.0 N/mm² @ 28 days |
| Young’s modulus (ASTM 469-83) | 28 kN/mm² |
| Drying shrinkage | <400 microstrain @ 7 days; <700 microstrain @ 28 days |
| Setting time (ASTM C953:1997) | Initial 5.5 hours; Final 6.5 hours |
| Fresh wet density | Approximately 2300 kg/m³ |
| Maximum application thickness | Up to 100 mm in a single section |
| Water : powder ratio (test basis) | 0.12 at 30°C |
| Mix water (flowable) | 3.0 litres clean water per 25 kg bag |
| Chloride admixture content | Nil |
| Recommended primer | Nitobond AR / Nitobond SBR |
| Recommended curing | Concure curing membrane / water / wet hessian |
| Packaging | 25 kg moisture-resistant bags |
| Shelf life | 12 months in sealed bags, dry storage |
Industry use cases
Logistics & Warehousing
Reinstating deep impact and forklift damage in distribution-centre and warehouse floor slabs across NCR logistics parks, with the 24-hour strength gain allowing racking aisles to reopen quickly.
Manufacturing & Heavy Industry
Repairing production-area floors and machine-base surrounds that suffer point loading, abrasion and chemical spillage, where a low-permeability structural repair restores both strength and durability.
Parking Structures
Full-depth repair of car-park decks, ramps and bays where chloride and carbonation-driven deterioration has spalled the slab; the chloride-free, low-permeability matrix protects reinforcement against further corrosion.
Infrastructure & Public Buildings
Restoring loading docks, service yards and heavily trafficked institutional floors where a flowable, self-levelling micro-concrete is faster and more reliable than trowelled patching.
Cold Stores & Food Processing
Reinstating slab areas in hygienic, heavily washed-down environments where a dense, low-permeability repair that resists fluid ingress is essential.
Frequently asked questions
What exactly is Fosroc Renderoc SM and how is it different from Renderoc S or Renderoc HB?
How thick can Renderoc SM be applied in one pour?
How much water do I add, and can I add more to make it flow better?
When can the repaired floor be put back into service?
Do I need a primer and a curing compound?
Does Space Arc Engineering supply Renderoc SM across India?
How we position Fosroc Renderoc SM
Within the Fosroc range, Renderoc SM is the floor-repair member of the Renderoc concrete-repair family: where Renderoc S and Renderoc HB are trowel-grade mortars for vertical and overhead reinstatement, and Renderoc RG is a general-purpose micro-concrete for reinforced sections, Renderoc SM is specifically the flowable micro-concrete for deep horizontal slab repairs — pour it where you would otherwise struggle to trowel. It pairs with Nitobond AR/SBR primers and Concure curing membranes to form a complete repair system. Against competitor systems, Renderoc SM competes with Sika’s MonoTop / SikaGrout micro-concrete repair range, MBS (MYK / BASF Master Builders Solutions) MasterEmaco flowable repair concretes, Dr. Fixit’s Pidicrete and structural repair micro-concretes, and STP (Sika-owned) repair products. The honest position: for large-area, deep floor reinstatement where flow and shrinkage compensation matter most, Renderoc SM is a proven, widely specified choice; for thin overlays or fairing coats, look to Renderoc FC, and for non-floor structural repair, the trowel-grade Renderoc mortars are the correct selection. Space Arc Engineering can advise on the right grade for each defect type rather than forcing a single product onto every repair.
Related Concrete Repair products
Source Fosroc Renderoc SM for your project
Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.