Description
Atlas Bejca Birch is shade 08 of the ten-colour Atlas Bejca range and the palest of the birch, teak, walnut and ebony shades Renders World keeps on the shelf. It is a semi-transparent tinted impregnant for Cermit WN wood-texture render, supplied in a 4-litre pack covering 16–20 m² a coat.
What Atlas Bejca Birch Is
Bejca has one purpose: a thin coloured protective coating on Cermit WN decorative render, the surface pressed into the texture of natural timber. The tone comes from semi-transparent pigments of high UV resistance with small additions of inorganic pigments. On the palest shade in the range the semi-transparency counts for more than anywhere else, because less pigment stands between the eye and the render — a grey Cermit WN under Atlas Bejca Birch does not give the same wall as a white one.
- Binder: low-molecular polymer dispersions blended with silicone resins.
- Permitted backgrounds: Cermit WN, concrete, mineral renders of every kind, gypsum plasters and fillers, plasterboard.
- Shade 08 of ten: 01 alder, 02 pine, 03 walnut, 04 oak, 05 mahogany, 06 tekwood, 07 rosewood, 08 birch, 09 ebony, 10 acacia.
Atlas Bejca Birch comes in a 4-litre pack, storage life 12 months from the production date printed on it.
Rain Out, Vapour Through
Two of the figures Atlas gives concern water, and they point in opposite directions on purpose: the coating keeps liquid water out while letting vapour leave the wall.
| What is measured | Value | What it means on the wall |
|---|---|---|
| Water absorption, 24 h | 200 g/m² or less, over Cermit WN | liquid water stays out of the render |
| Relative diffusion resistance | 1.0 m or less | vapour still leaves the wall |
| Scrub resistance | over 5000 strokes, PN-C/81913 | a pale wall can be washed |
The absorption figure belongs to the pair, not to the coating on its own: Atlas measured it with Cermit WN below, so it describes that build-up and no other. The hydrophobic behaviour comes from the silicone resins, and Atlas credits them specifically with reducing how much dust and dirt sticks in the recesses of the render — which on a pale plank is the first place anyone would notice it.
Coverage, and How Many Packs a Wall Takes
Consumption is given per litre rather than per pack: 4–5 m² from one litre at a single coat. The pack holds 4 litres, so 4 L × 4–5 m²/L gives 16–20 m² per coat. The Atlas data sheet adds that exact consumption is settled by a trial on the substrate to be painted.
- Divide the area by 16 m² per pack per coat and round up. A 40 m² elevation takes three packs for one coat.
- Multiply by the number of coats. One or two layers are both permitted, and no second coat is required.
- Run the trial on the render you are actually using. A pale shade moves further with the background than a dark one, so the panel decides the look as well as the quantity.
Laying On Atlas Bejca Birch
The background is seasoned first. Cermit WN takes at least 3 days, new cement render at least 14 days at 2 % moisture, concrete at least three months under 2 %, and gypsum substrates and boards under 2 %. Those periods hold for setting at +20 °C and 50 % air humidity. The background is dry, sound and free of contamination before anything goes on it.
- Substrate and air between +10 °C and +30 °C, air humidity under 80 %, and not on a strongly sunlit elevation.
- Stir thoroughly with a slow-speed paint mixer. Never thinned, never mixed with anything else.
- Brush, roller or sponge, worked along the pressed grain, one even thin layer, every recess covered and nothing left bare.
- Coating of one production date on one surface, and tools washed in clean water straight afterwards.
Bejca dries in roughly 30 minutes, widening to two hours with substrate, temperature and humidity, and early resistance to rain comes after some 24 hours; until then the face is kept clear of dust and rain. Sprayed application means masking the adjoining facade, the windows and the doors first. There is also a two-stage aged-plank method, in which the tone is worked back with a sponge and then protected with a coat of transparent Bejca — a separate product that Renders World does not stock.
Where It Sits in the Method
Atlas Bejca Birch is the last of four steps, and the other three are on the same shelf.
- Cermit WN mineral render — some 4 mm thick, roughly 2.5–3.0 kg per square metre, 25 kg bags, with the grain pressed in 20 to 60 minutes after laying.
- Silicone wood stamp, 200 × 20 cm — forms the plank.
- Anti-adhesive agent for silicone moulds — the Cermit WN documentation requires the mould greased thoroughly before use, without qualification.
- Our step-by-step guide to decorative effect renders runs the sequence end to end; our guide to sealers for decorative renders covers the shades.
Birch Against the Other Three Shades
Renders World keeps birch, teak, walnut and ebony of the ten. Since the shades differ in pigment alone — same binder, same consumption, same permitted backgrounds, same pack — the choice is a choice of tone and nothing else, settled on a stamped sample rather than on paper.
- 08 Birch — this one, the palest, and the one that lets most of the render below show through.
- 06 Teak — the warm mid tone, the everyday board colour.
- 03 Walnut — a cooler, deeper brown for contrast against pale render.
- 09 Ebony — the darkest, and the one the dark-colour caution is aimed at.
Technical Data and the Limits
| Property | Value |
|---|---|
| Density | 1.02 kg/dm³ |
| Consumption | 4–5 m² per litre, one coat |
| Pack | 4 litre bucket |
| Application temperature | +10 °C to +30 °C |
| Air humidity during the work | under 80 % |
| Drying | 30 minutes to two hours |
| Early resistance to rain | after about 24 hours |
| VOC content | under 129.9 g/l, category A/f/FW |
| VOC permitted | 130.0 g/l for that category |
| Storage life | 12 months from the production date on the pack |
| ATLAS ETICS kit | ITB-KOT-2020/1616, issue 3 |
| ATLAS ROKER kit | ITB-KOT-2021/1919, issue 2 |
| ATLAS ROKER EPS kit | ITB-KOT-2020/1188, issue 1 |
Excluded on horizontal surfaces, on surfaces under permanent direct action of water and snow, and where damp rises by capillary action. Four things carry no number in the Atlas documentation and therefore carry none here: a dose in kg/m², a requirement for a second coat, an HBW value for an individual shade, and a service life or repaint interval.
Questions Buyers Ask
- Does a pale shade stay clean? Atlas gives no soiling figure, so there is nothing to quote. What it does state is that the silicone resins cut water absorption to 200 g/m² or less over 24 hours with Cermit WN below, and reduce how much dirt sticks in the recesses.
- Can the wall be washed? Resistance to scrubbing is over 5000 strokes to PN-C/81913. Atlas sets no washing schedule, so frequency is a judgement rather than a specification.
- Is Atlas Bejca Birch technically different from the other three shades? No. Nothing in the Atlas documentation separates the ten on any property but pigment.
- Will the render colour show through? Yes, more than under any other shade stocked here, which is the reason the sample panel is laid on the render that will actually be used.
Technical Documentation
- ATLAS BEJCA karta techniczna, update date 2023-09-04 (PDF)
- ATLAS BEJCA Technical Data Sheet, English edition, update date 2023-04-05 (PDF)
Atlas Bejca Birch is the shade to pick when the timber is meant to look light. The rest of the method, and the teak, walnut and ebony shades beside it, sit together in our range of decorative effect renders.