Primer for Cementitious Substrates Sika SIKACERAM-935 — 5 kg

Sika SIKACERAM-935 is a water‑based primer formulated for use on cementitious substrates. Supplied in a 5 kg pack, it is intended to equalise surface absorption and consolidate porous cement floors and screeds prior to the application of tiles, ceramic coverings or levelling compounds. The primer promotes a stable and uniform substrate to help achieve consistent adhesion of subsequent ceramic or coating systems.

Advantages

The primer improves adhesion between cementitious substrates and tile mortars or levelling compounds by reducing and equalising surface porosity. Its water‑borne formulation allows easy application with a roller or brush and dries to form a uniform film that reduces dusting and loose particles. Supplied in a ready‑to‑use 5 kg packaging, it is suitable for preparing larger areas and supports reliable bonding of tiles and finishing layers.

Suitable for

• Preparation of cement-based floors and screeds before tiling
• Use prior to application of levelling compounds and smoothing mortars
• Sealing porous or dusty cementitious surfaces to reduce absorptivity
• Interior floor areas where a consistent substrate is required for ceramic coverings

When it may not be suitable

This primer is formulated specifically for cementitious substrates and is not intended for use on non-absorbent surfaces such as glazed tiles, metals, or dense natural stone without appropriate pre-treatment. It should not be used as a waterproofing membrane or as a structural bonding adhesive. For substrates contaminated with oils, greases, or other residues, thorough cleaning or a different primer type is required before application.

Key specifications

• Form: water‑based primer
• Application: internal cementitious floors and screeds
• Container size: 5 kg
• Suitable top layers: ceramic tiles, tile adhesives, levelling compounds
• Function: absorption equalisation and surface consolidation

How to use

Ensure the substrate is clean, dry and free from dust, loose material, oils and curing compounds. Stir the primer before use and apply evenly with a short-pile roller or brush to achieve full surface coverage. Allow the primer to dry according to ambient temperature and humidity until a uniform film is formed and the surface is no longer tacky. Once dry, apply the chosen tile adhesive, cementitious levelling compound, or ceramic system according to their respective instructions.

What to consider before purchase

• Confirm that the substrate is cementitious and absorbent — not suitable for dense non‑absorbent materials without pre-treatment
• Assess the area size to ensure a 5 kg pack provides sufficient coverage for your project
• Plan for adequate drying time based on site temperature and humidity
• Verify compatibility with the specific tile adhesive or levelling compound to be used

Usage recommendations

Apply at recommended temperatures and relative humidity; avoid application in freezing conditions or under heavy rain. For best results on highly porous surfaces, a second coat may be applied after the first coat has dried. Always follow the instructions of the subsequent tile adhesive or levelling compound manufacturer for optimal bonding performance.