Sika CemCrete
A multipurpose acrylic polymer that turns site cement into a waterproof slurry coat, a reliable bonding bridge and a modified repair mortar, all from one liquid.
What is it?
A milky-white acrylic polymer emulsion that is blended with cement and sand on site to make waterproof slurry coatings, bonding coats and polymer-modified mortars.
Where is it used?
RCC roof slabs and terraces, sunken slabs, basement tanking, water tanks, sumps and salt-affected masonry across residential, commercial and infrastructure projects.
Why use it?
One economical liquid replaces separate bonding agents, waterproofing admixtures and mortar modifiers, cutting the number of products a contractor has to stock and coordinate.
How is it applied?
Gauge with cement at 1:2 for a brush-applied slurry, or 1:2:2 with sand for a brush topping; power-mix at 300-500 rpm and apply in two coats onto a saturated, sound substrate.
About Sika CemCrete
Sika CemCrete is one of those workhorse products that quietly does three jobs at once. At its core it is an acrylic polymer emulsion, a milky-white liquid that you gauge with ordinary site cement and, where needed, clean silica sand. Blend it one way and you get a brush-applied waterproof slurry for a terrace or a sunken slab; blend it another and it becomes a bonding coat that helps fresh concrete or plaster grip an old, tired surface; add sand and it modifies a repair mortar so it sticks better and lets less water through. For a contractor juggling a dozen line items on a purchase order, that versatility is the whole appeal.
Because it works with materials already on the job, CemCrete suits the realities of Indian sites rather than fighting them. There is no proprietary powder to import, no exotic mixing rig; a paddle mixer on a drill and a mason who knows how to strike off a slurry are enough. It is widely specified for the recurring headaches of our climate and construction practice, leaking RCC roofs, damp basement walls, water tanks that need an internal seal, and old masonry disfigured by efflorescence and saltpetre. Space Arc Engineering supplies it as an authorised Sika distributor and applicator, so the same team that quotes the material can also advise on surface preparation and coats.
The technical insight
The performance comes down to what the acrylic polymer does to a plain cement paste. On its own, cement mortar cures into a rigid, porous matrix riddled with capillary channels that pull water straight through by capillary action. When CemCrete is mixed in, the polymer particles coalesce into a continuous film that laces through those pores as the mortar hardens, physically blocking the capillary paths and lowering permeability. That same film chemistry is what improves adhesion; the polymer wets and grips both the substrate and the fresh mortar, which is why a CemCrete slurry develops a tensile adhesion of the order of 0.5 N/mm2 rather than simply sitting on top. It also raises the material’s tolerance to salt movement, so on leaching or saltpetre-affected walls the coating resists the migration that would otherwise keep pushing white deposits back to the surface. In short, you are not adding a coating over the concrete so much as re-engineering a thin cementitious layer to be denser, stickier and far less thirsty.
Where it is used
- Waterproof slurry coating on RCC roof slabs, terraces and sunshades
- Waterproofing of sunken slabs in toilets, bathrooms and utility areas
- Internal and external tanking of basements and retaining walls
- Internal waterproofing of water tanks, sumps and reservoirs
- Bonding coat between old concrete and new concrete, screeds or plaster
- Polymer-modified repair mortar and plaster for patch repairs
- Anti-efflorescence and saltpetre treatment on leaching, damp masonry
- Composite coating with glass-fibre mesh and silica sand for added toughness
Key advantages
- One product serves as waterproof coating, bonding agent and mortar modifier
- Mixes with site cement and sand, no proprietary powders to source
- Applied by brush at slurry consistency with only a paddle mixer needed
- Good tensile adhesion, around 0.5 N/mm2, to sound cementitious substrates
- Reduces permeability and resists salt permeation in the cured layer
- Effective on the common Indian problems of leaching and saltpetre staining
- Economical dosage keeps per-square-metre cost predictable for estimators
- Backed by Space Arc as an authorised Sika distributor and applicator
Limitations & considerations
- Not a standalone crack-bridging membrane; it is a semi-rigid cementitious coating and will not span moving cracks or dynamic joints
- Waterproofing depends on correct on-site gauging with cement, so mix ratios and coat counts must be controlled to get repeatable results
- Needs a sound, clean, saturated-surface-dry substrate; it will not cure friable, oily or loose surfaces
- Application is limited to roughly +10 C to +40 C, so peak-summer and cold spells need scheduling around
- For structural cracks, expansion joints or heavy hydrostatic pressure a dedicated flexible membrane or system is required instead
Selection & best practice
Start with substrate: cut out loose concrete, rake out cracks, remove laitance and dust, and pre-wet the surface to a saturated but surface-dry condition so it does not steal water from the coating. For a waterproof slurry, gauge CemCrete with fresh cement at 1:2 by weight and power-mix at 300-500 rpm for two to three minutes to a lump-free, brushable consistency, mixing only what can be used before it stiffens. Apply the first coat well-worked into the surface, let it become touch-dry, then apply the second coat at right angles to the first for full cover; on demanding areas embed glass-fibre mesh between coats. Turn the coating up at all wall-floor junctions and around penetrations, cure it from drying too fast, and protect it before laying screed or tiles. Work within +10 C to +40 C and confirm dosage and coats against the current Sika technical data sheet for the specific exposure.
Specifications
| Chemical base | Acrylic polymer emulsion with special additives |
| Appearance / colour | Milky-white liquid |
| Density | Approx. 1.04 kg/L at +27 C |
| pH value | Approximately 8 |
| Mixing ratio (slurry) | 1:2 (CemCrete : cement) by weight |
| Mixing ratio (brush topping) | 1:2:2 (CemCrete : cement : sand) |
| Tensile adhesion (as slurry) | Approx. 0.5 N/mm2 |
| Application temperature | +10 C to +40 C |
| Shelf life | 12 months in unopened, sealed packing |
Industry use cases
Residential roofing
Waterproof slurry coat on RCC terraces, chajjas and sunken bathroom slabs to stop the seepage and damp patches typical of Indian rooftops.
Water-retaining structures
Internal sealing coat for overhead and underground water tanks, sumps and reservoirs where a dense, low-permeability cementitious layer is wanted.
Basements and podiums
Tanking of basement walls and retaining structures against soil-side dampness, applied as a composite system with mesh on demanding areas.
Repair and rehabilitation
Bonding bridge between old and new concrete and as a polymer-modified plaster or patch mortar during structural repair works.
Heritage and old masonry
Anti-efflorescence treatment on leaching, saltpetre-affected brick and plaster walls to check recurring white salt deposits.
Frequently asked questions
Is Sika CemCrete a waterproofing coating or an admixture?
Where do I use CemCrete and where should I not?
How much CemCrete do I need per square metre?
Can it stop leaks in an existing terrace or bathroom?
What packs is it available in and what is the shelf life?
Does Space Arc supply and apply CemCrete across India?
How we position Sika CemCrete
Within the Sika range, CemCrete is the versatile, cement-gauged workhorse; where a project needs a factory-blended two-component flexible coating, Sika’s own cementitious systems in that family are the natural step up, and Sika Latex sits alongside as a bonding and mortar-improving polymer for repair work. Across the brands Space Arc carries, specifiers wanting a proprietary two-component elastomeric membrane for terraces and wet areas often move to Dr. Fixit or Fosroc cementitious coatings, while heavy negative-side or high-hydrostatic situations may call for a crystalline or membrane system rather than a semi-rigid slurry. Our technical team will match CemCrete against these alternatives on cost, flexibility needed and exposure so the specification is honest rather than product-led.
Fosroc Brushbond RFX — Choose Brushbond RFX when the deck or wet area genuinely moves and needs a factory-blended, two-component flexible coating with crack-bridging, rather than CemCrete’s site-gauged semi-rigid slurry.
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