Sealing a wood-effect render is the step where the colour arrives, and Atlas treats it as part of the system rather than an optional finish. Two Atlas documents were read this session — the Cermit WN technical sheet and the Atlas step-by-step guide for the timber facade — and they set the timing, the method and the protection this page describes.
They also disagree with each other on one figure, which turns out to be the most useful thing on the page. Everything below stays inside what those two documents cover; the concrete effect render range holds the three shades stocked here, and the tinted impregnate is the only sealer either document names.
What the Tinted Impregnate Does, and Why It Is Not Optional
Sealers for concrete effect renders UK projects specify are not a general-purpose masonry treatment: Atlas Bejca is a thin coloured protective coating made for Cermit WN decorative render imitating natural wood texture, and Atlas describes it as part of its thermal insulation systems rather than as an aftercare product.
That places it inside the specification, not after it. The Cermit WN sheet declares its V2 – medium vapour permeability category with the tint applied, so the coloured surface is the condition the manufacturer's declaration actually describes. A bare stamped render is an unfinished system, which is the strongest reason to plan the sealing day into the programme from the start.
Atlas also names the substrates it will go onto beyond that render: concrete, all types of mineral render whether smooth or textured, gypsum render and putty, and gypsum plasterboard. That list is broader than the timber effect alone, though the product's stated purpose remains the wood-textured coating.
When to Seal: Two Atlas Documents, Two Different Answers
Here the documents part company, and the divergence is worth more than either figure alone. The Cermit WN technical sheet states the render is hard after 24 hours and may be covered with the Bejca tinted impregnate after three days, quoted at +20 °C and 50% humidity. The Atlas step-by-step guide for the same wood-effect facade states the mass is hard after 24 hours and may be covered after five days.
Same manufacturer, same two products, same operation. Treat the longer figure as the working one: wait five days before the tint goes on, and understand the three-day line as the earliest the render is chemically ready under laboratory conditions of +20 °C and 50% humidity — conditions a UK site rarely holds for three consecutive days. Where a programme genuinely cannot accommodate five days, that is a conversation with Atlas technical rather than a judgement made on scaffold.
The practical reading is straightforward. Book the sealing day for the fifth day after stamping, keep the scaffold up until it is done, and treat any cool or damp spell during those five days as a reason to extend rather than compress. The stamping method guide covers the render work that precedes this, and the concrete effect render application guide carries the substrate and system side.
How to Apply the Tinted Impregnate to a Stamped Facade
The method below is transcribed from the Atlas step-by-step guide, which sets out the sealing stage as its fourth and final operation.
- Mix it properly first. Stir the impregnate thoroughly before use. Atlas recommends doing this mechanically with a slow-speed drill and mixing attachment, though it can be done by hand.
- Choose the applicator. Brush, roller or sponge — all three are named. Where the tint is sprayed instead, adjacent facade areas and window and door frames must be carefully covered with facade netting first.
- Work along the grain. On Cermit WN the tint is applied along the pressed rings of the plank, following the grain direction the mould created rather than across it.
- Keep the coat thin and even. Apply in a uniform, thin layer that prevents runs and missed patches. Every recess and hollow in the wood pattern must be properly covered — Atlas states plainly that leaving unpainted places on the facade is not permissible.
- Divide the planks before it dries. Before final drying, the surface is divided horizontally and vertically at the plank joints with an imitation joint or bossage, by whichever method suits the detail.
- Leave it, or age it. The prepared surface can simply be left to dry, or aged deliberately by wiping it gently with a slightly damp sponge.
Two protection instructions carry real weight on a UK site. The impregnate is not used on strongly sunlit sections of the facade, and treated surfaces are shielded from direct sun before application and for about 24 hours afterwards, using protective netting on the scaffold. Until the impregnate has dried completely, the coloured surface is also kept away from dust and rain.
That makes sealing a weather-dependent operation in its own right, not a job to squeeze into the last hour of a scaffold hire. Following the sun round the building — working the shaded elevation and letting the netting do the rest — is what keeps colour consistent across a facade.
Choosing a Shade, and What Each One Costs
The Atlas guide describes the tint as available in ten colours. Renders World stocks three of them, all in 4-litre tins at £69.00 each, read from the product pages in August 2026 with no VAT figure displayed.
| Shade | Pack and price, Aug 2026 | Where it tends to suit |
|---|---|---|
| Birch | 4 L, £69.00 | The palest of the three — a bright, light timber read |
| Teak | 4 L, £69.00 | The warm mid-tone, and the most commonly specified hardwood look |
| Walnut | 4 L, £69.00 | The deepest of the three, for high-contrast elevations |
No consumption figure is published here, because the Bejca product sheet sits on an Atlas host that refuses every fetch and no mirror was found this session. That means no litres-per-square-metre rate, no tin count and no per-m² cost — the figures previously on this page had no document behind them. Ask the Renders World trade desk to confirm consumption against your measured area before ordering, and order the whole facade in one go so the shade is consistent across it.
One point about colour depth does come from the documents. Because the coating is described as thin and coloured rather than opaque, and because the render beneath it is white, the cured render tone and the depth of the pressed grain both affect how a shade reads on the wall. A trial on a stamped sample panel, viewed dry and in daylight, is the reliable way to choose between birch, teak and walnut.
Key Takeaway: Wait five days after stamping before the tint goes on — the longer of the two figures Atlas publishes — then apply it thin and even along the pressed grain, covering every recess, and keep the surface out of direct sun for 24 hours afterwards.
Planning the Sealing Day Around Weather and Scaffold
Everything that goes wrong at this stage traces back to timing rather than technique, so the planning is where the effort belongs.
- Book day five, not day three. Set the sealing date from the stamping date and hold the scaffold for it, so the wait is a planned line in the programme rather than an overrun.
- Work the shaded elevation. Atlas rules out strongly sunlit sections, so follow the shadow round the building and use scaffold netting on the elevations you cannot avoid.
- Mask before you mix. Where the tint is sprayed, Atlas requires adjacent facade areas and window and door joinery to be covered with netting first — worth doing for brush and roller work too.
- Keep a wet edge to a plank line. The surface is divided at the plank joints before it dries anyway, so ending a section at a joint puts any unavoidable break where the detail already is.
- Protect it overnight. Dust and rain stay off until the impregnate has dried completely, and direct sun stays off for around 24 hours.
For the render that sits under all of this, Atlas Cermit WN is the mineral render the impregnate is made for, and the rendering materials range at Renders World holds the primer, the mould and the release agent that complete the four-product system. Confirm shade and quantity with the trade desk, and the sealing day becomes the straightforward final step it should be.
Written by Mariusz Saja. Technically reviewed by Renders World Team. Last reviewed Aug 2026.
FAQ — Timing, Coverage and Compatibility
How long after rendering can the sealer go on?
Atlas publishes two figures for the same operation: three days on the Cermit WN technical sheet, at +20 °C and 50% humidity, and five days in its step-by-step guide for the wood-effect facade. Work to five days, since the shorter figure assumes laboratory conditions that a UK site seldom sustains, and extend further if the spell has been cool or damp. Both documents agree the render is hard after 24 hours, which is a different thing from ready to tint.
How much sealer will a facade take?
No consumption figure is published here. The Bejca data sheet sits on an Atlas host that refuses to serve documents, and no alternative mirror was retrieved this session, so any litres-per-square-metre rate would be unsourced. The trade desk can confirm consumption against a measured area, and ordering the full facade in one batch keeps the shade consistent.
Can the render be left unsealed?
The Cermit WN sheet declares its V2 vapour permeability category with the tint applied, so the sealed surface is the finished condition the manufacturer's declaration describes, and Atlas presents the impregnate as part of its insulation systems rather than as an optional extra. Bare Cermit WN is also white — the colour is the point of this step. Treat sealing as part of the specification.
Will it work on substrates other than the wood-effect render?
Atlas states the coating can also be used on concrete, all types of mineral render whether smooth or textured, gypsum render and putty, and gypsum plasterboard. Its stated purpose remains the thin coloured protective coating on Cermit WN imitating natural wood. For anything outside that primary use, a trial area confirms both adhesion and the final shade before a facade is committed.
What about south-facing elevations in summer?
Atlas is direct on this: the impregnate is not used on strongly sunlit sections of the facade, and painted surfaces are protected from direct sunlight before application and for approximately 24 hours after it, with protective netting on the scaffold. Plan the day to follow the shade round the building, and net the elevations where that is not possible.