Sika SikaTop-107 Seal IN
A two-part, acrylic polymer-modified cementitious coating that seals concrete and masonry against water ingress — potable-water safe, crack-bridging and brush-applied.
What is it?
A two-component waterproofing coating: a liquid acrylic polymer (Part A) blended on site with a cement-and-aggregate powder (Part B). No extra water is added — you mix only the two supplied parts.
Where is it used?
Potable water tanks and reservoirs, terraces, balconies, sunk slabs, toilets and kitchens, basement and retaining walls, swimming pools, lift pits, RCC gutters and planter boxes.
Why use it?
It is approved for potable-water contact, bonds to damp substrates, bridges hairline cracks, resists chloride and carbonation, and cures fast enough to overcoat in about 4 hours.
How is it applied?
Prime the substrate wet, mix Part A:Part B at 1:4 by weight, then brush or trowel two coats crosswise at roughly 1.5 kg/m² each for a 1.2–1.5 mm system. Cure for 7 days.
About Sika SikaTop-107 Seal IN
SikaTop-107 Seal IN is Sika’s long-standing, general-purpose cementitious waterproofing coating for Indian construction — formerly sold as SikaTop Seal-107 IN. It is a two-part system: Part A is an acrylic polymer liquid, and Part B is a Portland-cement-based powder carrying selected aggregates and admixtures. Mixed together, they produce a grey slurry that is brushed or trowelled directly onto concrete, plaster, brickwork or blockwork to stop water infiltration. Because the polymer replaces the mixing water entirely, the cured film is far more flexible and less permeable than a plain cement slurry, while staying easy to apply with ordinary site tools.
For engineers and contractors, the appeal is versatility across the widest range of everyday waterproofing situations — the same 25 kg set works on a terrace, a sunk-slab toilet, a lift pit or an internal water tank. It is supplied pre-batched, so there is no on-site guesswork over dosage, and it bonds to damp substrates, which suits Indian sites where surfaces are rarely bone-dry. The product is approved for potable-water contact, backed by an SGS toxicity certificate to IS 6582 and a CFTRI clearance for repeated contact with water and aqueous foods to USFDA 175.300, which is why it is a routine specification for drinking-water tanks and reservoirs.
The technical insight
The waterproofing works on two fronts. The acrylic polymer forms a continuous flexible film that laces through the hydrating cement matrix, so instead of a brittle, porous cement skin you get a dense, elastic membrane bonded integrally to the substrate. That film closes off the capillary pores through which water normally wicks into concrete, giving the tested result of near-zero water penetration at 5 bar pressure over 72 hours (BS EN 12390-8). The polymer also delivers around 10% elongation at break, enough to bridge the fine, non-moving hairline cracks that let water in through otherwise sound concrete. Because the coating is applied to and cures on a pre-wetted, damp surface, it develops a strong tensile adhesion bond (≥2.0 N/mm²) rather than sitting as a loose skin — so it resists the back-pressure of water and the chloride and carbonation attack that corrode reinforcement. Crucially, no water is added during mixing: the polymer liquid is the only liquid phase, which keeps the water-to-cement ratio low and the film tight.
Where it is used
- Interior lining of potable concrete water tanks, reservoirs and waste-water tanks
- Waterproofing terraces, balconies, sunshades and small or flat roofs
- Sunk slabs, toilets, kitchens and utility wet areas
- Basement and retaining walls, and lift pits and sumps
- Swimming pools, fountains, water bodies and canals
- RCC gutters, drains and planter boxes
- Damp-proofing of concrete, cement render, brickwork and blockwork
- Pore and blowhole filling, and sealing fine non-moving hairline cracks
Key advantages
- Approved for potable-water contact (SGS to IS 6582, CFTRI to USFDA 175.300)
- No mixing water required — the polymer liquid is the only liquid, keeping the film dense
- Pre-batched components give consistent quality and remove on-site dosage errors
- Bonds well to damp substrates, so surfaces need not be fully dry
- Flexible enough to bridge non-moving hairline cracks (~10% elongation)
- Resists chloride penetration and carbonation and reduces saltpetre action
- Fast curing — a second coat can go on in about 4 hours
- Applied by brush, squeegee or flat trowel with standard site equipment
Limitations & considerations
- Bridges only fine, static hairline cracks — it is not a system for moving or structural cracks or expansion joints
- Rigid-side coating with limited elongation; for high crack-bridging demand a more elastomeric membrane is a better fit
- Larger or high-demand areas need Sika Fabric-50 glass-fabric reinforcement between coats
- No water may be added under any circumstances — doing so weakens the film
- Must not be ponded or immersed before 7 days, and needs full 7-day wet curing
- Do not apply in direct sun or strong wind; protect fresh coating from rain and frost
Selection & best practice
Prepare a sound substrate (minimum pull-off strength 1.0 N/mm²) free of laitance, oil, curing compounds and loose material, and form a 25 mm x 25 mm mortar fillet at all horizontal-to-vertical junctions. Pre-wet the surface thoroughly — around two hours is recommended — then remove standing water so it reads dark and matt, not shiny, before you coat. Pour the full Part A into a clean container, add Part B while stirring with a slow-speed paddle mixer (300–500 rpm), and mix about 3 minutes to a lump-free slurry; use it within the ~40-minute pot life. Brush the first coat in one direction, let it harden for 2–6 hours, then apply the second coat crosswise. Seal pipe penetrations with SikaSwell S-2 or Sikagard 694 F(I), and embed Sika Fabric-50 at detailing points or across large areas. If the second coat is delayed past 12 hours, lightly re-wet the first. Cure with wet hessian or spray for a minimum of 7 days and keep off water immersion for the same period.
Specifications
| Product type | Two-part acrylic polymer-modified cementitious waterproofing coating |
| Chemical base | Part A: acrylic polymer liquid; Part B: Portland cement with selected aggregates and additives |
| Mixing ratio | Part A : Part B = 1 : 4 (by weight) |
| Consumption | ~1.5 kg/m² per coat; ~3.0 kg/m² over 2 coats |
| Layer thickness | ~1.2–1.5 mm in 2 coats |
| Water penetration | ~0 mm at 5 bar for 72 h (BS EN 12390-8) |
| Tensile strength / elongation | ≥2.0 N/mm²; ~10% elongation at break (ASTM D412) |
| Pot life / overcoat / cure | ~40 min pot life; ~4 h between coats; 7-day cure and water immersion |
| Packaging | Pre-batched 25 kg set (5 kg Part A + 20 kg Part B); 12-month shelf life |
Industry use cases
Water storage / utilities
Internal lining of RCC potable-water tanks, overhead and underground reservoirs, backed by SGS and CFTRI potable-contact certificates for safe drinking-water use.
Residential & commercial buildings
Waterproofing sunk slabs, toilets and kitchens beneath tiling, and treating terraces and balconies before screed or protective plaster.
Below-ground structures
Damp-proofing basement and retaining walls, lift pits and sumps against ground moisture and standing water.
Repair & rehabilitation
Sealing hairline cracks, filling pores and blowholes, and protecting concrete against chloride penetration, carbonation and saltpetre in ageing structures.
Landscape & water features
Lining swimming pools, fountains, canals, RCC gutters, drains and planter boxes that stay in prolonged contact with water.
Frequently asked questions
Is SikaTop-107 Seal IN safe for drinking-water tanks?
How much coating do I need per square metre?
Do I add water when mixing?
Can it be applied to a damp surface?
Will it bridge cracks in the concrete?
How long before I can tile or plaster over it?
How we position Sika SikaTop-107 Seal IN
SikaTop-107 Seal IN is the workhorse of Sika’s brush-applied waterproofing range — the right pick when you want one dependable, potable-safe cementitious coating across tanks, terraces, wet areas and basements. Within the Sika family, reinforce large or high-demand areas with Sika Fabric-50 glass fabric embedded between coats, seal pipe penetrations and construction joints with SikaSwell S-2 or Sikagard 694 F(I) epoxy putty, and pair it with SikaCeram tile adhesives and Sika SealTape F for a complete wet-room system. Where a project needs more flexibility and crack-bridging than this rigid-side coating offers, step up to a more elastomeric Sika membrane. Across our other brands, comparable two-part cementitious coatings include Dr. Fixit and MC-Bauchemie systems for teams already standardised on those supply chains; talk to Space Arc and we will match the product to the exposure, the certification you need and what your applicators know best.
Fosroc Brushbond RFX — A specifier standardised on Fosroc, or wanting an ASTM C836-referenced acrylic cementitious coating from that supply chain, would choose Brushbond RFX as the direct equivalent.
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