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The Ultimate Guide to Render Grain Sizes

The render grain size that you choose can have an effect on several factors; our EWI Pro thin coat renders come in a wide range of grain sizes, from 1mm to 3mm. The reason that our renders have grains of different sizes within them is so that you can achieve a textured effect based on your own preference – whether it’s only very slightly textured (1mm) or extra rough (3mm), we cater for all tastes! If you’re looking for a way to create a unique, aesthetically pleasing exterior facade for your property, then check out our blog post on render design features for some inspiration.

Many customers frequently ask us about how choosing a different grain size may affect installation and/or cost. Generally, we advise that the larger the grain size you go for, the more render you will need to buy because the coverage rates decrease with the larger grain sizes. For a comprehensive guide on how much a coloured render system costs, check out our blog ‘coloured render cost per m2’!

Grain size can also affect how easily the render can be applied. Based on our technical experience, we have listed our grain sizes with all the pros and cons associated and hopefully, this will elucidate the situation further!

1mm Render Grain Size

Our 1mm grain size is our smallest render grain size. It is therefore applied at a 1mm thickness which is the thinnest that our renders can be applied at (the thickness that you apply the render should match the render grain size). This also means that in terms of cost per square metre, the 1mm grain size will cost the least as, compared to the larger grain sizes, a bucket of 1mm will go the furthest.

In terms of aesthetic appearance, 1mm render grain size is the smoothest finish that we offer. Depending upon our personal preference, the 1mm will give you more of a painted look, which can look really nice on certain properties, or if you’re looking to mimic your previous render.

The only downside to the 1mm is that because it’s applied so thinly, any textural issues or trowel lines within the basecoat will show through the render. It can also be trickier to install because of this and because of the fact that it has to go on in such a thin layer. If you’re after 1mm, then make sure you hire a professional with a high standard of work to carry out the job for you.

1.5mm Render Grain Size

1.5mm is our most popular grain size and is the choice of most installers. This is because it’s easy to install, it goes far in terms of coverage so it’s very cost-effective, and because it’s more textured due to its slightly larger grain size, it also hides imperfections in the basecoat. Homeowners like this grain size because it doesn’t have a painted finish but it’s not overly textured – you can only really see it when you look closely!

2mm Render Grain Size

Noticeably, the larger the grain size the more tricky the render is to apply as the larger grain sizes can cause dragging and can be more challenging to spread over the substrate. Also, larger grain size means higher expense. Again, this is because you have to apply it in a thicker layer and therefore you get less out of a bucket. The true benefit of a 2mm grain size is that it hides imperfections within the basecoat and the substrate. Depending upon personal preference and whether you like a more bumpy, textured render, the 2mm can be a perfect choice, providing the benefit of ensuring that your render surface looks even.

3mm Render Grain Size

Buying a 3mm grain size render means it will cost the most overall. Again, this is because the larger the grain size the less the bucket will cover. Choosing a 3mm render grain size may cost the most, but it will give you the most textured finish – not quite a pebbledash but very noticeably textured even from a distance. Because it has such a textured finish, this means that it’s considered to be one of the hardest to install due to the fact that the size of the grains creates a dragging effect which can be harder to work with.


The grain size that customers go for is always varied and really just depends upon personal preference. Hopefully, this blog post made the difference in the grain sizes a little more clear will help the decision-making process! Worth mentioning is the fact that sometimes grain size may affect the way the render colour appears. Larger grain sizes can cause a shadowing effect which sometimes makes the render appear darker than it actually is. We recommend you order a coloured render tester pot to help with choosing colours!

Stay tuned for more content! We upload to our blog every Tuesday and Thursday; whether it’s answering frequently asked customer questions or giving all the details about each of our products – we aim to cover it all. Comment down below if you have any further questions or give us a call to speak to our technical advice team who are always happy to help.


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