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Graphenstone - GCS Exterior Heritage Silicate Masonry Paint



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Prices Include VAT

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Premium breathable paint suitable for lime renders without the premium price tag.

Graphenstone's GCS Exterior wall paint uses a combination of lime, silicate and natural minerals to create a beautiful matt paint. 

Perfect for use on lime render along with most other common surfaces such as mortar, brick, concrete, old paints, etc. The ideal choice for restoration work where there are multiple substrates to cover. 

Highly breathable (<0.08 SD value), Very low VOC (<1g/l), fantastic coverage (12-18m2 per litre) and hard-wearing thanks to the graphene technology. Best in class coverage per litre. 

Drying time: Quick drying 2-4 hours between coats, 24 hours until fully dry, 30 days until fully cured.

Approx coverage: 12-18m2 per litre (supplied as a concentrate - dilute 10-15% with water before application). 2 coats required. 

Primer: The Ambient Primer L42 is required before the use of the GCS exterior. L42 is perfect for use on new renders (including lime render) and older surfaces such as old lime wash and existing masonry paints. L42 equalises and stabilises these surfaces whilst maintaining very high levels of breathability. L42 has coverage of between 26-30m2 per litre and requires one coat before application of the top coat. (further guidance on more specialist cases is available below, or contact us for advice)

Colour Availability & Samples

The GCS Interior and Exterior ranges have no standard "White" colour. However, the colour "Glacier" is a perfect alternative and is very White.

Not all colours of the Graphenstone range are available on the GCS Exterior, notably darker colours. If the colour you are looking for is not on the above dropdown list, it's not available. If the colour you want is unavailable here, please consider the Grafclean Exterior if suitable as all colours are available.

For interior use, please view the GCS Interior or the Grafclean Interior. Sample pots for the Graphenstone colour range are only available in the Grafclean Interior.

As with all paints, we strongly advise the purchase of sample pots where available. We also offer colour cards free of charge to help you narrow down the colour for you - Order a Colour Card

Bespoke sample pots are available in this product on request. Sample pots are readily available for the Grafclean Interior paint, giving a fantastic indication of the colour. Don't hesitate to get in touch with us for more details. 


  • Exterior use
  • High covering power
  • Ultra Matt finish (3% sheen)
  • Very Low VOC, < 1 g/l
  • VOC emission: Class A+
  • Very Breathable, SD value: <0.08
  • Certified for moisture control
  • Tough and long-lasting
  • Excellent Washability: Class 1
  • Excellent flexibility - a non-cracking formula
  • High adherence to substrates
  • Fire rating: EU A2 s1, d0 (EU EN13501-1), Class 0 (British Standard)
  • Cradle to Cradle Certified SILVER
  • GreenRate Certified: Level A

Preparation, Application and Aftercare

Preparation: Mineral substrates must be at least 28 days old before application. This paint is highly alkaline therefore substrates must be resistant to high levels of alkalinity. Do not apply to surfaces in constant contact with water. If in doubt, apply to a test area first.

  • Ensure the substrate is dry, sound and clean.
  • If the substrate has salt deposits, brush and apply Graphenstone Neutralysal Premium.
  • If the substrate contains a high moisture level, use Graphenstone StopWater Premium.
  • When applying over glossy paint, sand the surface lightly to create a "key".
  • Remove flaking and unstable paint. Create a uniform surface with Graphenstone Filler Primer

Primer selection:

  • Ambient Primer L42 - Clear stabilising primer for use in most instances including new renders and lime renders, existing paints, including conventional masonry paints and lime washes.
  • Graphenstone Minerseal Premium - for very absorbent surfaces, i.e. clay, adobe, rammed earth etc. and for consolidating dusty mineral surfaces.

Application of the GCS Exterior:

  • Stir and dilute with water to 10-15% of the product weight (150-200 ml of water per litre of product approx.), ensuring a homogeneous mixture. Avoid excessive shaking to minimise bubbles. 
  • Apply 2 or 3 coats evenly by roller, brush or airless spray gun.
  • Note: Over application of the product by layers can generate micro-cracks.

Aftercare: Total curing occurs during the first 30 days. We recommend avoiding cleaning and rubbing the painted surface during that time. 

For more detailed information, download the Graphenstone GCS Exterior Technical Data Sheet and GCS Exterior Safety Data Sheet (MSDS)  (opens in a new tab). This documentation is for the pastel base used for lighter colours. Data sheets for other tinted bases used for darker colours are available on request. 

Other documentation and certification:

(All pdfs open in a new tab).