Monthly Archives: September 2018

The Best Basecoat for Rendering?

We’ve released some new branded slogan t-shirts! The ‘All About that Basecoat’ t-shirt is one of our favourites, and we think our installers will love to wear these on-site! In honour of the new release, we’ve written all about one of our top of the line basecoats – the Premium Adhesive! Have a read and check out the t-shirt pictures…

All About that Basecoat?

When it comes to finding the best basecoat, the Premium Adhesive ticks all the boxes. It’s incredibly strong, breathable and flexible to ensure a render system that lasts. We always recommend using the Premium Adhesive on painted or rendered substrates for strength and stability.

As a multi-purpose adhesive, the Premium Adhesive can be used in two ways: for securing insulation boards to a substrate, and as a basecoat before a thin coat render is applied.

Why use the Premium Adhesive?

Our Mineral Wool insulation system requires the use of the EWI-225 Premium Adhesive. This is because Mineral Wool insulation boards are much heavier than your basic EPS, so they require an extra strong adhesive – much like using super glue rather than plain old PVA.

We’ve previously written all about the difference between all of the EWI Pro adhesives in our ‘Ultimate Guide’ blog post, however to give a brief overview; the Premium Adhesive differs from our Basecoat Adhesive due to the fact that it is made of Portland cement, which is much stronger than other cements. It also contains stands of fibreglass within the material, ensuring extra tensile strength and flexibility. This means that the adhesive remains strong and stable, but also has a level of flexibility to ensure the render on top stays free of cracks.

As part of the reinforcement basecoat layer, the Premium Adhesive works well in conjunction with a Fibreglass Mesh, which is embedded within the basecoat. Each strip of mesh is overlapped, so any expansion or contraction of the external walls during heating and cooling will not cause the basecoat to crack because of the Fibreglass Mesh.

Why Choose a Breathable Basecoat?

Choosing a breathable basecoat with a breathable render finish (such as our Silicone Silicate render and Silicone render) ensures one key advantage; water vapour can pass easily through both layers of material.

This means that cracking and blown render will be significantly reduced, as well as build-up of damp within the render system. Breathable materials are also essential for older properties to ensure that the building fabric remains structurally sound.

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Common Mistakes during EWI Installations

Common Mistakes during EWI Installations

Life doesn’t always go to plan – sometimes during an EWI installation mistakes are made and things can go wrong. It’s always frustrating when something goes wrong, but rest assured there is usually a solution to the common mistakes that are made during EWI installations! We have a close relationship with all of our installers who come to us for technical advice when things don’t go as planned, which is why we know exactly how to fix the usual issues!

Our render and EWI systems are all highly specialist and need to be installed properly for full functionality. With that said, we do offer training sessions and the chance to become one of our approved installers if you attend. These sessions run every Thursday from 10am onwards and teach attendees all about our systems, how to install them and what the products are all about.

For installers who are just starting out, it takes a while to get used to the installation process, including on-site organisation, timings, materials and how best to use them. So with the intention of pre-empting any problems, here are a few common mistakes and solutions that an installer might face during an EWI or render-only installation.

On-site Planning and Organisation:

Installing EWI is a process that not only involves high skill but also careful planning. There are many things that require an installers attention, and slip-ups can easily cause a halt to on-site works, wasting your time and money! Here are a few things to do with planning and organisation that may go wrong…

Delivery doesn’t come on time

When ordering materials, careful planning needs to go into making sure you are ordering the right quantities and that you are ordering far enough in advance to ensure that the materials arrive in time for the job to start. It’s so frustrating when workers are idle on-site because the materials haven’t arrived yet; with some companies, delivery times can be slow and on-site delivery may not even be on offer. One of our key priorities at EWI Store is making sure that we offer next day delivery. We aim to get our materials out to installers as quickly as possible, and we even have our own delivery drivers to do the job to make sure it happens!

Furthermore, if you do find that your materials are late then feel free to pop down to our premises and pick up some starter tracks so that you can at least be doing something while you wait!

Weather Conditions

When it comes to EWI and render, careful attention must be paid to the weather conditions. The materials cannot be used at low temperatures (unless you’re using our Winter Adhesive and Mineral Render!) and they cannot be used when temperatures are too high. The installation process also cannot be carried out during rain, because as we know damp can inhibit the functionality of the insulation. Always be on top of things by keeping an eye on the Met Office weather updates, this way you hopefully won’t find yourself in a situation where all of your workers are on-site and unable to do anything due to rainy conditions!

Installer-Client Communication

Part of on-site organisation involves communicating with the client to ensure that your requirements in order to carry out the work are met. If you find that the client has gone off to work and left you without access to the property for water and electricity, then you may find yourself wasting money on bottled water and even a generator. Communication with the client is key to ensuring a smooth installation process!

Drying times

Different materials at each stage of the EWI installation process have different drying times. When materials aren’t left to dry for long enough, or they’re left too long and are no longer workable, you may find that the quality of your work is impeded upon. For example, when the basecoat is left too long in the bucket and then applied directly to the substrate without re-mixing it will set much quicker and its workability will be dramatically decreased, resulting in a not-so-smooth finish. Always pay attention to the drying times on the bag, and attend one of our training sessions where all of these things are covered!

EWI Materials and Common Mistakes:  

At EWI Store, we offer free training sessions for any installers who are keen to use our materials. Those that attend are then qualified as approved installers, which means they have the knowledge and know-how that is necessary for a successful installation. Unfortunately, sometimes things can go wrong with materials on-site, whether it’s user error or other. The following are some examples of these problems.

The render is applied too thick

Our thin coat renders are designed to be applied just a few millimetres thick. Most installers who have used EWI Pro thin coat renders before will know that the thickness of the application should match the grain size. So, if you’ve chosen a 2mm grain size then you should apply it at a thickness of 2mm.

For many installers it can take a while to get used to this, and often on the first few attempts the render is applied far too thick purely because installers are more used to working with plaster and cementitious products with thicker application rates. In order to fix this, the quickest method is to use a plastic render float to scrape the render back to the correct thickness. Make sure you keep an eye that all the workers are applying the render correctly, as if not you will need to act fairly quickly in order to scrape it back.

Plastic fixings break

Our plastic fixings are designed to be used with our EPS (expanded polystyrene) insulation boards. Plastic fixings will not be suitable if you are installing Mineral Wool or Wood Fibre insulation, as these materials are too heavy for the fixings to be able to hold their weight. Not only this, but all fixings need to go through both the insulation board and the substrate in order to be totally secure. If your fixings are breaking, then it could be that you aren’t drilling them in far enough. After a while you should be able to judge this by eye, but to be really sure you’re drilling far enough through then we recommend putting a piece of tape on the drill bit to indicate where you would stop drilling.

Basecoat and mesh can drag

When installing Fibreglass Mesh and embedding it within the basecoat layer, the mesh is first placed onto the basecoat and then, starting from the bottom, a trowel is used to drag the basecoat through the mesh, embedding it in the process.

With this technique the mesh can sometimes get caught, and rather than becoming embedded it is simply dragged back up the wall with the trowel creating a bit of a mess. To resolve this, we first  recommend making sure that the basecoat isn’t too wet before you attempt to embed the mesh. If this does happen, simply remove the mesh and start again, but if you find that there’s a tear in the mesh you will have to add another layer on top to reinforce this area.

There you have it! We hope that this was informative and helpful for those just starting out with EWI. Don’t forget to attend one of our training sessions which run every Thursday if you haven’t already. We upload new content every Tuesday and Thursday all about render and EWI, with information blog posts about different products, technical advice and answering customer’s FAQ’s.

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EWI Pro Adhesives: The Ultimate Guide

We’ve now gathered a pretty wide range of EWI Pro adhesives for our render and external wall insulation systems, but without any real clarification about which ones should be used with certain materials and in certain conditions.

Last time we talked about a specific range of our products, it was to provide an overview of our entire line of primers. This week we’re doing something similar and we are going to be talking about our range of adhesives and basecoats, so read on for more information!

EWI-210 EPS Adhesive

Our EPS Adhesive is designed for use purely for mounting EPS insulation boards onto a substrate. We only recommend using this adhesive for EPS because other insulation boards (Mineral Wool and Wood Fibre) are too heavy for it. It’s vapour permeable so will allow any trapped moisture to escape, all while maintaining a strong hold. This is a really versatile adhesive in that it can be used on almost any substrate, be it masonry, concrete, cement-lime or blockwork.

EWI-220 EPS Basecoat Adhesive

The EPS Basecoat Adhesive is designed to be used in two ways. As an adhesive, it is used to secure EPS insulation boards to the substrate (much like the EWI-210, but stronger). Secondly, it can be used as a basecoat for the mesh reinforcement layer. This is a really popular choice for installers because it has a dual purpose which limits the amount of products that are required on-site and also the amount of product that goes to waste.

EWI-221 Winter Adhesive

Much like the EPS Basecoat Adhesive, the Winter Adhesive is a dual-purpose product. It can be used as both basecoat and an adhesive, however the main difference here is that the Winter Adhesive can be used at temperatures down to zero degrees celsius (but no lower than zero) while still maintaining a strong adhesion. This is a fantastic solution to ensure that any hold-ups on-site due to winter weather issues are prevented.  

EWI-225 Premium Adhesive

This is our strongest and most flexible adhesive. It can be used as both an extra strong adhesive and an extra strong basecoat. We always recommend using this adhesive with Mineral Wool and Wood Fibre systems as this is a strong enough adhesive to be able to support the heavier insulation materials. The reason this is our premium adhesive is because it contains strands of fibreglass mesh within the material, which enhance its tensile strength and grip.

EWI-269 Lightweight Basecoat

Our Lightweight Basecoat is highly breathable and is perfect for heritage projects on substrates such as limestone and sandstone, and for use on high performance blockwork. This basecoat is not designed for use on top of insulation boards, but the good thing about it is that it can be applied at a thickness of up to 25mm in one pass without compromising its breathability. The Lightweight Basecoat also contains lime, which is why it’s so breathable and lightweight.

EWI-235 Dash Receiver

Last but not least is our Dash Receiver. In some ways the Dash Receiver is both adhesive and basecoat. It creates a smooth basecoat onto which the dash aggregates adhere to. The Dash Receiver is highly flexible and offers strong adhesion, so you can be sure it will remain crack free for years to come, while holding fast onto the dash aggregates.

EWI-104 Universal Tile Adhesive

The Universal Tile Adhesive is made a cement-based adhesive, with CT2E class adhesive capabilities. This is ideal for internal or external use and offers users a long correction time to enable the adjustment of tiles before it dries in order to achieve a perfect finish.

And there you have it! Our complete guide to EWI Pro adhesives. Any further questions, comment down below or get in touch with our technical team!

Recap: EWI Pro Adhesives

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Applying Coloured Render to Ziegel Block

New Ziegel Block Building, New Coloured Render

When thinking about applying a decorative finish to Ziegel blockwork, it’s important that the materials you are using compliment the substrate (we’ve written previously about failed renders caused by this). Ziegel blocks are known for fire safety, thermal performance and excellent indoor air quality. With that said, the right materials are required in order to compliment the functionality of the substrate and subsequently reduce cracking.

At EWI Store, we have a range of solutions for applying coloured render to high performance blockwork successfully, so let’s take a look at the process and the materials required to ensure crack resistance and a lasting finish.

Why Build with Ziegel Blockwork?

In order to understand the kind of render that would be best suited for Ziegel, we need to take a look at what exactly Ziegel blocks are and what properties they have. Ziegel blocks are renowned for being high performance because they have excellent insulating capabilities.

Their high thermal performance is due to the air channels that run vertically through each block creating a honeycomb effect, while the clay itself has more air pockets made by sawdust that is burned off in the kiln during the firing process. Ziegel blocks are also a breathable building material as they can maintain the equilibrium of humidity by storing and releasing heat and moisture, helping to maintain room comfort and healthy indoor air quality all year round.

Ziegel are also a highly dense material, creating a uniform substrate that offers reduced thermal bridging with a quick and easy construction process. Although Ziegel is a high performance block, it does need finishing with a protective layer to prevent weathering. This is where coloured render systems are ideal, because the technology of the system means that the substrates functionality is in no way hindered by the coloured render, instead the materials that go into the render system compliment the substrate.

Applying the Basecoat to Ziegel Block

Ziegel block creates a uniform, continuous substrate which is incredibly easy to render in terms of creating a smooth surface; the only area that requires close attention is using the right materials and the right method of application. You can decide based on the climate and weather conditions whether or not you need to apply a two-coat system or a three-coat render system for this kind of blockwork. The default for the UK tends to be the three-coat system because the Lightweight Basecoat and render on its own will not withstand the weather conditions.

Two-coat system:

The two-coat system consists of the application of the Lightweight Basecoat, then a tightcoat and then a render.

In a typical render system on an ordinary substrate, a substrate primer would be necessary to limit the absorptive capacity of the substrate. However, when rendering a Ziegel substrate, to limit the absorptive capacity of the substrate you do not need to prime. Instead, you spray apply a first pass of the Lightweight basecoat at approximately two thirds of the thickness it should be applied at – around 12mm. You leave this to ‘pull back’ and dry slightly before appyling the final one third to take the basecoat up to its total thickness.

The Lightweight Basecoat needs to be left for a period 0f 24-48 hours to dry, then the tightcoat is applied. This consists of another thin layer of the Lightweight Basecoat; it is applied to the dried basecoat and is sponged or rubbed up to achieve the required texture. Once the tightcoat has been applied, it can be primed and painted or primed and rendered using a ready-mix render (e.g. Silicone or Silicone Silicate). You can also use Mineral Render (and then paint with Silicone Paint) or you can use Monocouche render. The main thing here is that the tightcoat must be primed if you are using a ready-mix render such as Silicone or Silicone Silicate, because otherwise blooming may occur across the lime basecoat.

Three-coat system:

A three-coat system is the standard system that is recommended for use in the UK. The three coat system involves applying the Lightweight Basecoat in two passes, as outlined above. Once the Lightweight Basecoat has cured (after 24-48 hours), a layer of the Premium Adhesive with Fibreglass Mesh embedded is then applied on top. The Premium Adhesive is then primed using a render primer, before the render of your choice is applied; whether it’s Silicone, Silicone Silicate, Mineral or Monocouche.

The reason that the Premium Adhesive is applied as an extra layer is because it is far stronger than the Lightweight Basecoat, and when applied with a Fibreglass Mesh embedded within the adhesive it provides the required tensile strength to be able to withstand harsh weather conditions without cracking.

Applying Silicone Coloured Render to Ziegel Block

When applying coloured render to a Ziegel substrate, we really recommend the use of Silicone Render as it’s incredibly flexible, breathable and hydrophobic. It will therefore resist any cracking, prevent water ingress and allow water vapour to escape from the building fabric. It’s currently our most high performance coloured render and is an extremely versatile and popular solution for a wide range of substrates.

Silicone Render can also be tinted to create any shade of colour (hence the name coloured render). If coloured render is of interest to you, you can view our full shade range using our render colour chart, or you can purchase a coloured render sample pot.

For any further questions about applying render to Ziegel block, contact our technical team or leave a comment down below – we are always happy to help!

We upload a new blog post every Tuesday and Thursday, so stay tuned for more content!

Similar posts: applying coloured render to…

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Applying coloured render to render carrier board

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Essential Tools for Rendering and EWI

The best render and EWI jobs are those that you are most prepared for. At EWI Store, our main goal is to make sure that every installer is fully equipped for their next EWI job with minimal fuss. When you go through EWI Store, you can find everything you need in one place, along with our technical expertise and installation advice which is always on hand. With that in mind, in no particular order, here are our essential tools that any installer should have on site with the relevant links so that you can pick up anything you need quickly and easily!

Essential trowels for rendering and EWI

Stainless Steel Trowel

If you’re a renderer, then you won’t be able to live (or do any work) without your trowel on-site. Our stainless steel trowels are reliable and hard wearing – fantastically multi-purpose in that they are ideal for use with our basecoats, adhesives, thin coat and thick coat renders. They help to apply the product super smooth and at the appropriate thickness.

Square Notched Trowel

The square notched trowel is a fundamental tool for any render or EWI installer. It’s primarily used to ensure that the basecoat is applied at the appropriate thickness and to smooth out the adhesive onto the back of the insulation boards.

Bucket Trowel

The bucket trowel is a pretty standard trowel, nevertheless it’s very handy for scooping, mixing and distributing – be it adhesive or render.

Plastic Render Float

If you’re using one of our thin coat renders, then this is a fundamental tool because you need to use it rub up the render after it’s been applied in order to get the textured finish. Using the plastic render float means that the individual grains within the render can be revealed.

Sponge Float

The sponge float is used on the basecoat layer to smooth out any trowel lines that were left during application. If you’re using a thin coat render, this is an essential step because any imperfections in the basecoat are sometimes visible through the render.

Corner Trowel

The corner trowel is primarily used to evenly distribute product around the corners and achieve a seamless finish. This is certainly a multi use tool as it is often necessary for the basecoat layer and the render top coat layer.


This one isn’t necessarily essential, but it is a timesaver. The Speedskim essentially allows you to rule off your basecoat, covering a wider area than an ordinary trowel it means that you can get a flat surface in less time and using less energy!

Essential tools for insulation

Mineral Wool Knife

For use with both mineral wool and wood fibre, this is a really handy knife to have on site because you can jab it straight into the insulation and start cutting. Great for if you need to cut the insulation to fit corners etc.

Spirit Level

Essential for making sure your starter track is straight, which in turn means your insulation is laid straight.

Steel EPS Rasp

Best practice for a good quality EPS installation is to use a steel EPS rasp to remove the oily layer that sits on the surface of the EPS, and create a key onto which the basecoat layer can bind.

EPS Wire Cutter

If you are installing EPS, a really handy tool to have on-site is the EPS hot wire cutter. Essentially, it melts the EPS so that you end up with super straight lines and you don’t get a rough jagged mess and polystyrene absolutely everywhere.

Industrial Hoover

When you are rasping back your EPS, you will inevitably find that it goes everywhere and blows about in the wind. Something really handy to have on site is an industrial hoover. This way, one worker can be rasping the EPS while another holds the hoover underneath ready to catch all the fall-out.

Other essential EWI and render tools to have on-site

Large Bucket

Essential for mixing adhesive and more. Also best practice for rendering (especially coloured render) is to decant all your render buckets into one large bucket so that you can mix them all together and ensure a uniform colour.

Drill and Two Batteries + Masonry Drill Bits

Pretty important if you are using mechanical screw fixings – plus, always have a backup battery! Handy bonus tip for drilling mechanical fixings is to use tape on the drill to mark how far in you need to drill the fixings.


You’ll need a decent hammer for your plastic/metal hammer fixings.

Measuring Tape

Speaks for itself really, you’ll need to measure up your insulation boards if you’re cutting them etc!

Spades, Brush, Dustpan

Other essentials. You may find yourself needing to dig up some plants in order to gain access/move them out the way of the system, especially if you’re insulating below the DPC.

Window Covers

One of the most important things is to be mindful that you are on someone else’s property. Therefore, it’s your responsibility as the worker to protect windows etc. from damage and from getting render dripped on them.

Ladders and Stepladders

Always necessary! Make sure you follow the ‘working from heights’ guidelines.

Tank of Water

If you’re working on a domestic property, sometimes access to water isn’t available. Having a tank of water for mixing materials can be a lifesaver, so think ahead and always check with the customer whether you can use their water supply.

Safety essentials to have on-site

Gloves, Hard Hat, Boots, Goggles, First Aid Kit

Always use protection. And by that we mean protective work gear so that you aren’t putting yourself at risk. That means wearing work boots to protect your feet from falling materials and tools, goggles for when you’re rasping the EPS, and a hard hat to wear while on scaffolding. And importantly, always always always have a first aid kit on site (and someone who knows how to use it!).

Mobile Phone

In this day and age, it’s rare to find yourself without a mobile phone. However, accidents do happen and being able to contact emergency services is crucial so make sure it’s fully charged and easily accessible in case of emergencies!

So there you have it! Your basic guide to the essential tools to have on site. Any further questions? Call our technical team who are always happy to help, or leave a comment down below.

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