EWI Pro Silicone Renders: Choosing the Right Finish for Your Home

Every external wall insulation system we install ends with the same decision: which render goes on top. At APEX EWI we work with the EWI Pro system range, and within that range the silicone renders do the heavy lifting on the vast majority of our projects. This guide walks through the four silicone finishes we install — EWI-040, EWI-075, EWI-076 and EWI-077 — and explains, in plain terms, which one makes sense for which kind of home.

Why We Reach for Silicone First

EWI Pro make several families of thin-coat render, including acrylic (EWI-010) and mineral (EWI-060) options, and a thick-coat monocouche scratch render (EWI-090) for a pitted sandstone-style effect. So why do silicone finishes end up on most of our jobs?

The answer comes down to three properties working together:

• Breathability. A silicone render lets water vapour pass out through the wall rather than trapping it. On an insulated solid-wall home, that matters — moisture generated indoors needs an escape route, and a vapour-open topcoat keeps the whole build-up healthy.
• Hydrophobic behaviour. The silicone content makes the cured surface shed rainwater instead of soaking it up. Water beads and runs off, carrying loose dirt with it.
• Self-cleaning. Because rain rinses the surface rather than sinking into it, silicone facades stay brighter for longer than traditional finishes. Less streaking, less green bloom, fewer weekends up a ladder with a pressure washer.

Silicone renders in this range also arrive ready-mixed in a tub — no site mixing, no water measuring — and they are through-coloured, meaning the pigment runs all the way through the material rather than sitting on the surface as paint. A minor scuff shows the same colour underneath, not a grey scar. Compare that with the mineral render, which is a dry-mix product that needs sealing with silicone paint after installation, and the appeal of a one-product topcoat is obvious.

The Four Silicone Finishes at a Glance

EWI Pro's silicone family runs from a value-focused hybrid to a top-tier formulation, and the honest summary is that all four will give you a breathable, weather-shedding, low-maintenance facade. The differences are in degree, not kind:

• EWI-040 Silicone Silicate Render — the hybrid entry point, blending silicate (mineral) chemistry with a silicone emulsion.
• EWI-075 Silicone Render — the standard full-silicone finish and by some distance the most commonly installed.
• EWI-076 Premium Bio Silicone Render — a step up in raw materials, with anti-fungal additives.
• EWI-077 Nano Drex Silicone Render — the flagship formulation, engineered for maximum water repellence and elasticity.

Below we take each in turn, with our view on where it earns its place.

EWI-040: The Value Hybrid

The Silicone Silicate render is a polymer-modified, through-coloured topcoat that pairs potassium silicate chemistry with a silicone emulsion. In practice you get most of what makes silicone renders attractive — breathability, flexibility, water repellence and resistance to biological growth — at a friendlier price point, which is why it often features on larger projects where the render bill is multiplied across a big wall area.

The trade-off is that its self-cleaning performance sits a notch below the full-silicone products. It also performs best in light and medium-strength colours, so if your heart is set on a deep charcoal facade, one of the finishes further up the range is usually the better call. For a typical semi in a sheltered street wanting a white or cream finish on a sensible budget, EWI-040 is a genuinely strong choice rather than a compromise.

EWI-075: The Everyday Favourite

If we could only stock one render, it would be EWI-075. This is EWI Pro's standard full-silicone formulation, enhanced with nano-particle technology for stronger hydrophobic performance, and it is the range's most popular product. It bonds to a wide variety of substrates — brick, concrete, render carrier boards, existing plasters and, of course, basecoated EWI systems — which makes it as useful on a re-render job as on a full insulation wrap.

For most homes in most locations, EWI-075 hits the sweet spot: excellent breathability, reliable self-cleaning, a full colour offering and a finish that still looks fresh years after the scaffolding comes down. When customers ask us what "the normal one" is, this is it.

EWI-076: Built for Exposed and Leafy Plots

Premium Bio Silicone render uses higher-grade raw materials than the standard silicone and adds anti-fungal additives to the mix. Two situations make it worth the upgrade:

• Green surroundings. Homes shaded by trees, backing onto woodland or sitting near water are more prone to algae and fungal growth on external walls. The biocidal boost in EWI-076 keeps organic growth at bay noticeably longer.
• Exposure. The formulation offers improved resistance to mechanical damage, which suits coastal properties and other homes that take a regular battering from wind-driven rain and debris.

If your property ticks either box, the extra outlay tends to repay itself in how the facade looks five and ten years in.

EWI-077: Top of the Range

Nano Drex is the most advanced silicone render in the EWI Pro stable [VERIFY: described as the newest flagship when launched in 2020 — confirm it still holds that position in the current product line-up]. It is engineered to be extremely hydrophobic, actively discouraging organic growth rather than merely resisting it, and it is formulated with high elasticity so the cured surface can move with the building and shrug off the hairline cracking that plagues rigid renders.

This is the finish we specify when a customer wants the best available — often on homes going for a bold, dark colour scheme, or where the owner simply wants the longest possible interval before the facade needs any attention at all.

Grain Size: The Texture Decision

Every finish above is available in a choice of grain sizes, which control the texture of the finished wall. The range runs from fine to coarse [VERIFY: one EWI Pro source quotes 0.5mm–3.0mm across the silicone range, another 1mm–3mm for EWI-075 — confirm current availability per product], and the practical guidance is straightforward:

• Finer grains give a smoother, more contemporary look but show substrate imperfections more readily.
• Coarser grains add texture and are more forgiving on walls that are not perfectly true.
• 1.5mm is the most popular choice across the range, and for good reason — it balances a clean modern appearance with everyday practicality.

Unless there is a specific architectural reason to go finer or coarser, 1.5mm is our default recommendation, and it is what you see on most of the finished projects in our gallery.

Choosing a Colour That Lasts

Because these renders are through-coloured, your colour choice is a long-term commitment — which is no bad thing, as it also means no repainting cycle. EWI Pro's own sales data shows neutral tones dominating: Pure White alone accounts for nearly a third of standard silicone render sold, with greys such as Smoke and Ash, off-whites and creams like Magnolia and Ivory, and stone-inspired shades such as Sandstone filling out the most popular picks.

Popularity is a useful starting point, not a verdict. The right colour depends on your roof, windows, brick detailing and the neighbouring houses — and on any planning conditions, since some properties sit under conservation or planning restrictions that constrain external finishes. It is always worth checking with your local authority before committing. Also bear in mind the product note above: very dark, high-contrast shades are best delivered in the higher-tier silicone finishes rather than EWI-040.

So Which Finish Is Right for Your Home?

A rough decision path, based on what we see across our installs: a sheltered property with a light colour scheme and a close eye on budget points to EWI-040; the typical UK home wanting a durable, low-maintenance facade lands on EWI-075; tree-lined, waterside or coastal plots justify EWI-076; and anyone wanting maximum longevity, maximum weather resistance or a deep, dramatic colour should look at EWI-077. Every home is different, though, and the surrounding conditions matter as much as the wish list — which is exactly what a site visit settles. If you are weighing up external wall insulation or a re-render, book a free APEX survey and quote, and try our render colour tool to preview the most popular shades on a facade before you decide.