Graphenstone GCS Exterior Silicate Masonry Paint Review

Graphenstone may be a new name to some of you, but they’ve been around – not just in the UK, but globally – for over ten years.

The whole ethos of the company is based around developing paints which are not only better for the environment in a general sense, but specifically for the air that we breathe in.

Their paints incorporate traditional natural materials like lime and other minerals, and combine them with graphene, which results in a highly durable coating which actively contributes to air purification and CO2 absorption – all without compromising on the finish.

Although I’ve run my own professional decorating business for getting on for twenty years, and I was aware of Graphenstone as a brand, I must confess that until a month or so ago I had never tried their products.  Recently however I had the chance to try their “GCS Exterior” silicate masonry paint, so I thought I’d write a review to let you know how I got on with it – I hope you find this useful.

Ambient Primer L42 Review

Having said that, I’m going to start with a few words on one of their other products, “Ambient Primer L42”.  The reason I mention it is that Graphenstone recommend using this first, to even out the porosity in the substrate and to stabilise dusty or chalky surfaces prior to painting.

On really sound, even surfaces it may not be strictly necessary, but it certainly won’t do any harm.  It’s basically a breathable primer/stabilising solution.  A little goes a long way, partly because you must dilute it 1:1 with clean water; it’s really hard to say just how far it goes though, because that will depend on how porous the substrate is.

On highly absorbent or breathable surfaces you will need a lot more of it than on a wall that has already been sealed with paint and is pretty non-absorbent, but there is still a benefit in using it, even in that situation, because it will help with any areas of chalky or flaky paint, and will help your top coats to bond better.

It’s a clear liquid that you can apply by brush, roller or spray, and is available in 1L, 4L and 15L sizes.  Although touch dry in a couple of hours, they recommend not painting your topcoats for 24 hours after application.  It’s not a “hero product” because nobody ever sees that you’ve used it, but it is easy to apply and seems to do a good job as a stabilising primer.

Graphenstone GCS Silicate Masonry Paint Facts & Figures

• Type of product – silicate masonry paint (meaning it is mineral-based rather than using synthetic binders).  Silicate paints are breathable, long-lasting and weather-resistant
• Suitable for – exterior masonry, brick, stone, concrete and render, including (especially!) heritage buildings and other surfaces where a breathable paint system is required
• Colours – available in Graphenstone’s extensive range of colours
• Sheen level – flat matt (approx. 2% sheen)
• Sizes – available in 1L, 4L and 15L
• Coverage – 10-14m²/L, depending on the substrate
• Drying time – touch dry in 1 hour, recoat in 2-4 hours, fully cured in 24 hours
• Application – brush, roller or spray
• Clean-up – water-based paint (clean tools with water and mild detergent)
• Available from – Many online retailers. Click here to see current prices.

Graphenstone GCS Silicate Masonry Paint in Use

The first thing you need to do when using Graphenstone GCS is to add some water to it – not because it’s unusually thick, but just because that’s what they recommend (and I always assume that the paint manufacturer knows their paint well!).

Not a lot – about 10% is normal, maybe slightly more if it’s a very hot day or you are painting a particularly porous substrate.  But once you’ve done that, you’re up and running.

It’s a nice paint to use, the consistency is great to work with, it flies on.  They do warn you not to spread it too thinly, and it’s worth listening to that advice, because it is very different to “normal” masonry paints in its make-up.

But it’s easy to use, and the finish is fantastic! Just solid flat matt gorgeousness! Unsurprisingly, it doesn’t have that slightly “plastic” look and feel that you can get with some “mainstream” masonry paints, it almost feels like stone.  It’s hard to describe, but I really like the look and feel of the finish.  And being flat matt, it’s also easy to touch up if you need to.

If I had to find one criticism, it’s that I was using a pale cream colour, and painting over some black marks did take three coats, but that’s hardly the end of the world, and would be the case with some of the other paints.

Review Summary

Silicate Masonry Paint Vs Normal Masonry Paint (Acrylic, Pliolite or Latex)

You may be reading this review because you need a silicate masonry paint, and Graphenstone came up because it’s a great product. In which case, you already know the difference between silicate and standard masonry paint.

However, just in case you don’t, I thought I’d add a quick note. The main advantage of using a silicate-based paint is its breathability. Not just water vapour (measured as an SD value), but droplets too.

This means that water will not get trapped in the substrate, making Graphenstone safer to use, especially on lime renders and similar substrates. Even normal cement renders can hold onto moisture, which is why most paints fail over time (water builds up behind the paint film and causes it to flake and peel).

Using a product like Graphenstone GCS Silicate Masonry Paint will mean your paint finish will last a lot longer, and it’s the product of choice for a lot of the decorators who specialise in painting English Heritage properties.