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There are 3 main types of render within our EWI Pro Insulation System range of BBA approved products – we offer a Mineral Render, Acrylic Render, Silicone Silicate Render. As you might expect we get asked a lot what the difference is between the types of render? Well in this blog we thought we would try and explain the differences so you can pick the right render for your next job!
Mineral Render
Our EWI Pro render is the only one to come as a dry mix – you need to add water to it before applying it. It also requires painting afterwards, which means it is a bit more time intensive to install. So why do people use it? Well there are a few reasons – firstly it is cheap in terms of material costs. Secondly mineral render dries much quicker than all the other types of render we offer so if you are installing in wet climates (I know most of the UK is normally under the water!) the this is the stuff to use – by the same token, this quick drying render is the one to use if you are installing in particularly humid or cold conditions since it will help minimise wash-off (when the render doesn’t stay in place due to rain or other unforeseen weather conditions!).
In terms of installs around the country, mineral render is particularly popular in both Wales and Scotland due to temperature and volume of rain. If you are doing the install yourself and it is during the summer months, the other renders just require the one coat (the colour is within the render itself) so you won’t have to paint anything once the render has been applied. Mineral render is also breathable and therefore compliments our Rockwool (mineral wool) insulation very well.
Once the mineral render has been applied it needs to be painted with our EWI pro Silicone paint which will provide a long lasting barrier to the elements and obviously can be coloured to your requirements.
Acrylic Render
What is Acrylic Render? Well for years has been the installers render of choice – it is essentially a render containing acrylic resin. Acrylic Resin is a type of plastic and added to render it helps offer better stain and water resistance as well as greater resistance to cracking. Our acrylic render comes pre mixed; this means that it can be applied straight on to the substrate (e.g. wall) without mixing it first with water. We sell the EWI Pro acrylic render pre mixed with your colour of choice and what is really great about it is when you opt for a vibrant colour, the acrylic render will hold this colour for a long time without fading (the other renders and the Silicone paint will fade over time so may require painting every 10 years or so).
Acrylic render is the cheapest render when you consider the labour and material costs – requiring just one application. If you are looking for the best value system then this in our opinion is the best and certainly a huge improvement on the old sand and cement renders of the past – it is flexible and will last 20 years plus. Before you use the acrylic render though just a couple of things to consider – firstly it is not breathable. The Acrylic Resin / plastic in this render means that nothing is going to get through it, therefore it is definitely not worth putting it on a breathable insulation product like our Rockwool as it sort of defeats the point! In addition, EWI Pro Acrylic render is not worth installing when the weather isn’t very good, so cold or wet as it takes longer to dry than the mineral render system. Finally Acrylic render is not as resistant to the elements as our Silicone Silicate render, so there will be some maintenance required like cleaning over time.
Silicone Silicate Render
This is now our installer’s render of choice – the EWI Pro Silicone Silicate render is ready mixed (much like our Acrylic Render) and therefore can be applied straight to the substrate. It is comprised of Silicone resin and Silicate. Once installed on the wall the Silicone Silicate render is hydrophobic, which basically means it repels water and therefore can be considered self cleaning in that the water will simply run off it.
The Silicone Silicate render comes in a few various different textures, but by far our most popular is the 1mm render. This means that within the render, it has Silicate granules just 1mm in diameter, so it can be applied extremely thinly on the wall – the advantage of this is that it is extremely flexible, so the house moves and the render moves with it. It simply won’t crack!!
Again, much like the acrylic render we don’t advise installing this render during the harsh winter months or when it is raining as the system does take a few days to cure – but once installed it should be maintenance free for over 20 years although it make require the odd pressure spray from time to time to keep it nice and clean. The EWI Pro Silicone Silicate render is completely breathable so is the ideal partner for our mineral wool insulation products.
If you would like to get a quote for any of these materials try our new materials calculator by clicking on the picture below
All the renders we sell in the EWI Pro Insulation System range are BBA Approved – Products that receive Agrément Certificates are recognised by building control, government departments, architects, specifiers and industry insurers. It’s a mark of quality, safety and reliability that provides reassurance that the product’s fit-for-purpose.
To learn more about the BBA and the EWI Pro Insulation System products please click here.
we were contacted by EWI pro at the end of last year. They promised great prices and great customer experience. From what we have witnessed so far they weren't wrong! If you are looking to install render / EWI then this is the one to use. The technical team are very knowledgable and they really do bend over backwards to help. The prices also about as competitive as you can find in the industry. If you do their training then you get discount card for this store. Very happy 🙂
We always use a Silicone based render. They are the easiest to apply and look very nice when finished. If you are looking to buy acrylic render then you should just get out the game. It is going to cause problems down the line as it bubbles when water tries to escape. Customers will come back!
Hi Dan, thanks for your comment. We normally advise customers to go for the Silicone render or Mineral render (if in damp / cold conditions) but there are still a huge number of installers out there who always buy acrylic render, I think just because this is what they have done previously and it does go on the wall nicely!
Hello do you sell silicone render with anti fungal solution. A quick response would be appreciated.
I want to render my home – we have a mid terrace and I want to know which product to use. We are putting an extension on at the moment so I think we will render that on top of the remaining wall to tie everything in together. If the extension is brickwork can the render go straight on to this? Also I have read about the base coat – do all the renders require this? Thanks.
Hi Susan,
If you are looking to render bare brickwork, we would always recommend adding the basecoat layer – this is the layer of adhesive that has the embedded mesh. This ensures not only a flat surface on which to render, but also makes the system flexible so it can move as the building moves.
We want to get our house re-rendered, but I am just wondering if the existing render needs to be stripped before applying the new render. It seems in relatively good shape on the whole but there are a couple of areas where it seems to be coming away from the wall a bit. I think the older houses just tend to move a bit more, which creates more cracking on the renders. How do these modern renders compare to the sand and cement renders from the older days? Can you get a warranty against cracking?
Hi DaveOmell, it really depends as you have alluded to on the existing render and how good it is. You can remove where it is coming away from the wall and use our filler to smooth the surface ready for the basecoat. If you are unsure how strong it is, we do recommend doing a pull test, this involves using our EWI-220 adhesive and sticking a few bits of the EPS insulation to the wall. Then try and pull the EPS off the wall. If the EPS comes away in your hand then the underlying render is sound. If when you pull the EPS, it comes away with the adhesive and the existing render then you are better off stripping that area of existing render before you start.
In terms of cracking, the new renders do tend to be better because they have a flexible basecoat layer – this is basically a layer of EWI-220 with our EWI-640 mesh embedded within it. To achieve this, the 220 is prepared with water as per the instructions to make a putty. It is then applied to the wall with a notched trowel and then turning the notched trowel over to the flat edge, embed the mesh into this adhesive. The total basecoat layer (sometimes referred to as the reinforcement layer) should be 4-6mm thick and ideally the mesh will sit within the middle of this. This gives these new render finishes a flexibility that you just don’t get with standard sand and cement renders. All the renders are also flexible (as per the article above) so when they are applied on the EWI-220 basecoat layer, you get a flexible system that should move with the natural movement of your property and therefore no more cracking!
Some installers do indeed offer warranties, we do run training with EWI Pro, one of our main system manufactures – if you go to their site you can find local installers who should 1. know what they are doing and 2. offer warranties!
To find EWI Pro installers click on the following link: http://ewipro.com/installers-directory/
Can I please ask what is the four layer silicone render? It has mesh as one layer and a choice of co!ours. It is apparently originally a German invention. Can this be put on in the winter months?
Reading this blog is actually quite upsetting since we asked our installer to install the best materials and he charged us more to install acrylic render. From what I read here it is definitely not a premium product. 🙁
We have been quoted Whetherby Silicone render from another company, I can’t seem to find the difference between the Silcone render and the Silicone Silicate render that you offer which I guess is the nearest equivalent?
Do any of these different types of render resemble pebble dash. While we don’t like the stone pebble dash, we do want to recreate the same texture. ANy help would be hugely appreciated.
Our external wall insulation installer quoted us for a Silicone render and now due to the colder weather he is suggesting Mineral render. Is there a difference in the look of the finish, as all the properties we went to see before picking this installer were silicone finish. Thanks in advance for your help.
We live in a woody area. I have read on line that some types of render go green if you live in these kind of places. Do you sell a render that will help prevent algae / vegetation taking hold on the render? Would it be the Silicone Silicate render?
Can any of the products be put onto a sand and cement backing (if its sound) as a refurb product
Hi John,
They all can, but start at the basecoat layer, so use EWI-220 + embed the mesh first. Once this has been done, let it go off, then prime the surface and apply the top coat render. Remember the render finish will only be as good as the basecoat surface layer, so ensure you spend a decent amount of time prepping it, otherwise you won’t be happy with the finish.
Links to products:
EWI-220 – Basecoat Adhesive
EWI-6640 – Fibreglass mesh
EWI-333 – SiSi Primer
EWI-040 – Silicone Silicate render
With regards to silicone render, I understand that it is extremely difficult to repair. i.e. the repair is still visible to the eye. What is your view?
Hi David,
Most renders are difficult to repair only in that the thickness of the rend is extremely thin when applied to the wall. The problem therefore is that when you come to repair it, the new layer of render does not seamlessly blend into the existing render. When render gets repaired, it normally requires patches to be applied, i.e. an area of wall around the damaged area is taped off (ideally a square) then the damaged material is cut out.