WOOD / CONCRETE / BRICK EFFECT RENDER

A concrete or timber facade effect is built from four things, not one: a primed substrate, a render that holds an impression, a mould released with the right agent, and a tinted sealer. Atlas publishes the whole sequence for its wood effect, down to the 5.25–6.0 litres of water per 25 kg bag.

What an Effect Render System Actually Contains

Concrete effect render is a decorative thin-coat finish that takes its character from tooling rather than from aggregate, and Atlas documents its timber version as a four-product system: Cermit WN render, Cerplast priming mass, an anti-adhesion agent and Bejca tinted impregnate. Each has a defined job.

Sitting inside the wider rendering materials range at Renders World, this collection covers three separate effects, and it is worth being clear which products belong to which, because they are not interchangeable.

• Exposed concrete — Atlas Silkon BA, a silicone render the manufacturer describes as imitating the texture of concrete and the structure of trowelled render, over a whole elevation, as bossage, or on fragments.
• Timber — Atlas Cermit WN with a silicone mould, the anti-adhesion agent and a Bejca shade, which is the sequence the Atlas step-by-step guide sets out in full.
• Brick — reusable stencil sets that pattern a decorative render coat into a stretcher or linear bond.

Why an Effect Render Rather Than the Real Material

The case for these systems is practical rather than decorative, and four points carry it.

• The finish is a render, so it goes where render goes. Atlas scopes Cermit WN to ETICS build-ups on both polystyrene and mineral wool, and to even mineral substrates such as concrete and traditional cement or cement-lime render.
• One product reaches inside and out. Silkon BA is documented for ETICS on EPS boards, for prepared mineral substrates, for old ceramic tiles once primed with Atlas Ultragrunt, and as an interior render including in showers.
• Texture is a tool decision, not a stock decision. The same bag of Cermit WN becomes plank, board or grain depending on the mould pressed into it, so a change of pattern late in a job does not change the material order.
• Colour goes on after the texture. Bejca is a thin coloured protective coating made for Cermit WN wood-effect render, and the Atlas guide lists it in ten ready-made shades, so the timber tone is chosen once the grain is already on the wall.

Match the Product to the Effect You Are Building

Read down to the effect you have been asked for, then across to the product that produces it. The specification column carries the fact that decides the row rather than a full data table, which belongs on each product page.

Prices read from the product pages in August 2026, all in GBP and all showing in stock: Renders World lists Cermit WN at £24.80 per 25 kg bag, Silkon BA at £79.50 per 20 kg bucket, the Bejca teak tin at £69.00 for 4 L, the anti-adhesive at £40.70 for 5 L, each brick stencil set at £116.70, the Atlas plank mould at £162.90 and the Fox hand stamp at £11.40. Bejca is also stocked in walnut and birch at the same 4 L format.

The two stamps are a scale decision rather than a quality one. The Atlas mould measures 2.00 m × 0.20 m, so 2.00 × 0.20 = 0.4 m² per impression, and a 40 m² gable needs 40 ÷ 0.4 = 100 impressions as an absolute floor — more in practice, because the Atlas method has each press overlapping the one before it. The hand stamp costs a fraction of that and suits the areas the big mould cannot reach.

How the Atlas Wood-Effect Sequence Runs on Site

This is the one route in the collection that Atlas documents end to end, and the timings are what make it work.

1. Prepare and prime. The substrate needs to be stable, clean, dry and even, then primed with Atlas Cerplast priming mass — the exterior render primers range holds it, and Renders World also lists Atlas Base Coat Paint 10 L as the tinted base the concrete-effect products are sold with.
2. Mix to the sheet. 5.25–6.0 litres of water per 25 kg of dry mix, stirred mechanically, rested five minutes and remixed. Use it within the hour and add no further water.
3. Lay two coats. The first at aggregate-grain thickness, the second at roughly 3–4 mm, evened with a 10 mm notched trowel held at 45° and then smoothed flat.
4. Wait for the set. Texturing starts once the render has initially set and dried on top, which Atlas puts at 20 to 60 minutes depending on the weather that day. Mark a level line before the first press.
5. Press with two people. Coat the mould with the anti-adhesion agent and roll it textured-face out; one operative unrolls and presses, the second rolls it back so it does not tear away. Overlap each previous impression and clear residue from the mould cavities as you go.
6. Colour after five days. Bejca goes on with a roller or brush in the direction of the pressed rings, in a uniform thin coat with no cavity left uncoated, and the surface is kept off direct sun, dust and rain until it is fully dry.

The step-by-step concrete effect application guide covers the substrate side in more depth, and the Bejca sealer guide works through the shade choice.

Three Details From the Atlas Guide Worth Knowing First

• Twenty centimetres is the mould width, and it matters. Where the pattern is meant to read wider than the standard 20 cm mould, Atlas says not to press the upper edge of the mould — that single instruction is what stops a plank facade looking like a grid.
• Re-coat the mould at least every second press. Skipping it is the usual reason a grain pattern starts pulling render off the wall halfway up an elevation.
• Tint the primer to the joint colour. On the brick method Atlas is explicit that the priming mass shows through as the mortar joint, so the primer colour is chosen to match the joint rather than the brick — the brick and timber stencil guide covers the two-colour sequence.

Where Each Render Is Documented to Go

The two renders are often described as an exposed-versus-sheltered pair, and the manufacturer's own scoping does not support that split, so it is worth setting out plainly.

• Atlas Cermit WN is scoped to decorative thin-layer and protective renders on the exterior of buildings, within ETICS using polystyrene and mineral wool, and on even prepared mineral substrates. Its stated purpose is a surface imitating wood texture imprinted with a silicone mould.
• Atlas Silkon BA is scoped to ETICS using polystyrene boards, to prepared mineral substrates, and to old ceramic tiles after priming — and Atlas positions it for interior use including showers, which is a wider indoor scope than the mineral render carries.

No coverage rate, service life or vapour figure is published on this page for either render, because none appears in the documents retrieved for them. Where a quantity is needed for a tender, the honest route is a sample panel at the intended coat thickness, and Renders World will supply the current manufacturer sheet on request.

Choosing Your Route Through the Range

• Timber effect: Cermit WN, a mould, the anti-adhesion agent and one Bejca shade — four lines on the order, and the only fully documented sequence here.
• Concrete effect: Silkon BA on its own, since the texture comes from trowel technique rather than from a separate stamp or sealer stage.
• Brick effect: a stencil set plus a decorative render coat, and worth a call before ordering so the render pairing is confirmed against current stock.
• Plain coloured facade: if the brief only needs a weatherproof coloured finish, a standard thin-coat silicone render does that job with none of the texturing stages.

For most projects the concrete effect render decision starts with a single bag and a trial panel: Atlas Cermit WN Smooth Render 25 kg at £24.80, August 2026, is the cheapest way to test how the grain reads on your own wall before the scaffold goes up.

FAQ — Quantities, Pairings and Timing

How much material does an elevation take?

Coverage rates are not published here for the renders, because no consumption line appears in the documents retrieved for Cermit WN, Silkon BA or Bejca. What can be sized is the tooling: at 0.4 m² per impression the Atlas mould needs a minimum of 100 presses for 40 m², and each stencil set is a 15-sheet pack listed at 15 m².

Which products belong together?

Bejca is made for Cermit WN wood-effect render and also works on concrete, mineral renders, gypsum render and plasterboard. The anti-adhesion agent belongs to the mould stage of that same sequence. Silkon BA carries its own texture and sits outside the stamp-and-sealer chain.

How tight is the texturing window?

Twenty to sixty minutes after the render is laid, depending on the weather — that is the span in which the surface has set enough to hold an impression and stayed soft enough to take one. Planning a wall area that two people can press inside that window is the whole trick, which is why Atlas specifies a two-person operation.

Silkon BA or Cermit WN?

Effect first, substrate second. Silkon BA produces the concrete and trowelled-render look and is the one documented for interior wet areas; Cermit WN is the mineral render made to hold a timber impression and is the one scoped to mineral wool build-ups as well as polystyrene. Neither is positioned by the manufacturer as the sheltered-elevation option.