Sika SikaTop 121
Sika SikaTop 121
SikaTop®-121 is a two-component, fiber reinforced, polymer modified, cement-based repair mortar for protection and repair of concrete surfaces. It is used for thin layer rendering, surface levelling, filling blowholes and honeycombing, protective coatings for bridges and retaining walls, and rendering for reservoirs. Features good mechanical strengths, excellent adhesion and high chloride salt resistance.
SikaTop-121 — Fiber Reinforced Polymer Modified Repair Mortar
SikaTop®-121 is a two-component, cement-based, polymer modified, trowelable adhesive and filling compound for the protection and repair of concrete surfaces. Component A is a white liquid polymer and Component B is a grey powder containing cement, selected aggregates and additives. The fiber reinforced formulation provides good mechanical strengths and high resistance to chloride salts.
Key Features
- Pre-batched two-component product with consistent quality
- Fiber reinforced — user-friendly application
- Good mechanical strengths (compressive strength ~25–30 MPa at 28 days)
- Excellent adhesion (tensile adhesion strength > 2 MPa at 28 days)
- High resistance to chloride salts — suitable for coastal and salt-spray environments
Applications
- Thin layer render — thin layer rendering of concrete surfaces
- Levelling of surfaces — levelling irregular concrete surfaces
- Protective coating — for bridges, parapets, retaining walls and similar structures
- Filling compound — filling blowholes, fine honeycombing and surface irregularities
- Reservoir rendering — rendering for reservoirs, ponds and water-retaining structures
Why Choose SikaTop-121?
SikaTop-121 is a thin layer rendering and levelling product in the Sika concrete repair range, ideal for high-quality surface finishing:
- Fiber reinforced: Contains fiber for improved crack resistance and workability
- High chloride resistance: Suitable for coastal environments or structures exposed to salt spray
- System compatibility: Works with SikaTop®-122 concrete repair mortar — use SikaTop-121 as the pore sealer and levelling mortar, SikaTop-122 as the structural repair mortar
- Sika brand: Swiss Sika — over 100 years of proven quality and reliability
- Easy application: Can be applied manually with a trowel
For concrete repair mortars, browse our concrete repair range.
Packaging
| Item | Specification |
|---|---|
| Packaging | 25 kg set (Component A + Component B) |
| Appearance (Component A) | White liquid |
| Appearance (Component B) | Grey powder |
| Shelf Life | 12 months (store in dry area in original sealed packaging, protect from direct sunlight) |
Technical Specifications
| Parameter | Value |
|---|---|
| Chemical Base | Cement, selected aggregates and additives |
| Density (fresh mortar) | ~2.0 kg/l at +25°C |
| Compressive Strength (28 days) | ~25–30 MPa |
| Tensile Strength in Flexure (28 days) | ~5–7 MPa |
| Tensile Adhesion Strength (28 days) | > 2 MPa |
| Mixing Ratio (by weight) | A : B = 1 : 4–5 (depending on required consistency) |
| Consumption | ~20 kg of fresh mortar per cm thick per m² |
| Yield | 25 kg set yields approx. 12.5 litres of mortar |
| Layer Thickness | Minimum 2 mm / maximum 5 mm |
| Application Temperature (ambient & substrate) | +5°C to +35°C |
| Pot Life | ~45 minutes at +30°C |
Important Notes
- DO NOT ADD WATER — mix strictly to the A:B ratio
- Avoid application in direct sun and/or strong wind and/or rain
- Protect freshly applied material from freezing and rain immediately after application
- Apply only to sound, prepared substrate
- Do not add additional water during surface finishing — this will cause discolouration and cracking
- Concrete substrate must be thoroughly clean, free from dust, loose material, surface contamination and materials that reduce bond
- De-laminated, weak, damaged and deteriorated concrete must be removed to sound substrate by suitable means
- Steel reinforcement must be free from rust, scale, mortar, concrete dust and loose material — prepare by abrasive blast cleaning or high pressure water-blasting to Sa 2 (ISO 8501-1)
- Pre-wet the substrate thoroughly (recommended 2 hours prior) — keep surface wet but with no standing water, showing a dark matt appearance with no visible surface pores
- Mix with a low speed drill mixer (< 250 rpm) for minimum 3 minutes
- Apply a scratch coat first by firmly scrapping repair mortar over the surface, then build up layers from bottom to top
- Protect during curing with curing compound, moist geotextile membrane or polythene sheet to prevent premature drying
- Clean all tools with water immediately after use — hardened material can only be removed mechanically
FAQ
What is the difference between SikaTop-121 and SikaTop-122?
SikaTop-121 is a thin layer rendering and pore-sealing/levelling mortar with 2–5 mm application thickness, designed for concrete surface finishing and levelling. SikaTop-122 is a concrete repair mortar for deeper structural repairs. They work as a system: use SikaTop-122 for structural repair, then SikaTop-121 as the surface levelling and finishing layer.
Can SikaTop-121 be used for waterproofing?
SikaTop-121 is primarily a concrete surface repair, levelling and protective coating mortar — it is not a dedicated waterproofing product. For waterproofing needs, consider the Sika cementitious waterproofing range (e.g. SikaTop-300 Seal). Please WhatsApp us for the right solution.
What is the maximum application thickness of SikaTop-121?
Each layer can be applied from minimum 2 mm to maximum 5 mm thick. For greater total thickness, apply in multiple layers. Consumption is approximately 20 kg of fresh mortar per cm thick per m², and a 25 kg set yields about 12.5 litres of mortar.
How is SikaTop-121 applied?
Shake Component A (liquid), pour into a container, add Component B (powder) while mixing with a low speed drill mixer (below 250 rpm) for at least 3 minutes. Do not add water. Pre-wet the substrate thoroughly (recommended 2 hours prior). Apply a scratch coat first by firmly scrapping mortar into the surface to fill pores, then build up layers from bottom to top to required thickness. Cure immediately after application. Refer to the Sika product data sheet for detailed instructions.
How much does SikaTop-121 cost?
Please WhatsApp us for the latest SikaTop-121 pricing. We offer self-pickup from our Mong Kok store and Hong Kong delivery service.
