Bostik Cementone Colour for Cement Black 1kg

What Is Bostik Cementone Colour for Cement - Black? 

Bostik Colour for Cement in Black is a high-quality, concentrated powder pigment specifically formulated to colour cement-based mixes such as concrete, mortars, renders, and screeds. 

Utilising lightfast pigments, this admix disperses easily and evenly into dry mixes, allowing you to achieve consistent, durable black or varying shades of grey. 

The pigments used conform to EN 12878: 2005, a European standard for pigments used in the colouring of building materials based on cement and/or lime. 

When used as directed, it imparts rich colour without negatively impacting the performance or strength of the final cured material, suiting it to a wide array of interior and exterior applications.

How It Works

The pigment is added directly to the dry cement and other dry components (sand, aggregate) within a mix. 

Thorough dry mixing before the addition of gauging water ensures the fine pigment particles are evenly distributed, resulting in a consistent, through-coloured material once cured, rather than just a surface coating.

Achieving Your Desired Black or Grey Shade

The intensity of the black or the specific shade of grey achieved is determined by the dosage of the pigment relative to the cement content, as well as other factors:

• Mix Ratios (by weight):
  • Normal Use (Standard Black/Dark Grey): A common starting point is 1 part Black pigment to 20 parts cement by weight. For example, this equates to 1.25kg of Black pigment per 25kg bag of cement.   
  • Darker/Deeper Blacks: To achieve a more intense black, you can increase the dosage up to a maximum ratio of 1 part Black pigment to 10 parts cement by weight (e.g., 2.5kg of Black pigment per 25kg bag of cement).
  • Lighter Shades (Greys): For various shades of grey, reduce the amount of Black pigment relative to the cement content.
• Factors Influencing Final Colour:
  • Cement Type & Colour: The colour of the cement used (e.g., standard grey Portland cement vs. White Portland Cement) will significantly impact the final shade. White cement will yield cleaner, brighter greys and can help achieve a more intense black.
  • Sand & Aggregate Colour: The natural colour of the sand and aggregates will also influence the perceived colour, especially in mixes with a higher aggregate content or for lighter grey shades.   
  • Water Content: The amount of gauging water can affect the final shade and its consistency. Use the same water-to-cement ratio for all batches.   
• Ensuring Colour Consistency:
  • Always measure ingredients, including the Black pigment, by weight, not by volume, for accuracy.
  • For large projects, use the same grades and sources of cement, sand, and aggregates throughout.
  • It is highly recommended to use Black pigment from the same batch number for a single continuous application. If using multiple batches, pre-mix the pigment powders together.
  • Always conduct a small trial mix with your specific materials and allow it to dry and cure fully before commencing the main work. This is crucial for assessing the final colour and ensuring it meets your expectations, especially when matching existing work.

Applications for Black Pigmented Mixes

• Concrete: Pathways, driveways, patios, floor slabs, pre-cast elements.
• Mortars: Creating striking black or grey pointing for brickwork and blockwork, offering contrast or complementing dark masonry units.
• Renders: Achieving durable black or grey decorative finishes on internal or external walls (e.g., modern architectural features, garden walls).   
• Screeds: Producing black or grey coloured floor screeds, including granolithic floors, for a distinctive industrial or contemporary look.

Benefits 

• Intense, Lightfast Black Colour: Specially formulated with carbon black for deep, rich black tones that are resistant to fading from UV light.   
• Uniform & Easy Dispersion: The fine powder consistency ensures it mixes evenly into the dry components for a consistent colour distribution throughout the mix.   
• No Performance Compromise: When used according to directions (not exceeding the maximum dosage), it does not negatively affect the setting time, strength development, or final durability of the concrete, mortar, render, or screed.   
• Versatile Application Range: Suitable for a wide array of interior and exterior uses where a black or grey coloured cementitious finish is desired.   
• Customisable Shades: Dosage can be easily adjusted to achieve anything from a subtle grey to a deep, solid black.

Application Guidelines

• Safety First: Before use, always refer to the relevant Health & Safety Data Sheet available from Bostik.
• Dry Mixing is Key: Add the Bostik Colours for Cement - Black powder directly to the dry cement.   
• Thorough Dispersion: Mix the pigment and cement thoroughly first. Then, add the dry sand and aggregate (if used) and continue to mix until the black pigment is evenly dispersed throughout all dry components. This step is crucial for achieving a uniform colour.
• Adding Water: Gradually add the gauging water and mix to the desired consistency.
• Enhancing Colour Retention (Optional but Recommended):
  • For mortars and renders, to reduce the possibility of efflorescence (white salt deposits that can mar dark surfaces) and lime bloom, and thus improve long-term colour retention, consider adding Bostik Mortar Plasticiser to the mix at its recommended dosage.
  • For external rendering, to further reduce efflorescence and improve weather resistance, adding Bostik Integral Waterproofer at its recommended dosage can be beneficial.