WALL “CONCRETE IMITATION”

  Materials and tools needed for a wall of ~ 15 – 17 sq. m.:

• Mr. Clay white decorative clay plaster (25 kg) – 1 piece 
• Mr. Clay Decorative clay – marble putty 10 kg. FINISH No. 9 (10 kg) – 1 piece  
• 132_B No pigment for decorative clay plaster. x 1 pcs. (two layers of plaster in the same colour)
• 134_B No pigment for the third FINISH Nr. 9 layer– 1 piece 
•  Tung oil  2,7 L.  
• Hardwood charcoal ~ 20g.
• Black mineral pigment for concrete streaks effect 134_B – 37,5 g. (1 litre of water per 10 g dry black pigment)
• Trowel for plastering and polishing Marmorino tools Stil mirror light 21102 
• A sketch board on which you will make your example, test the colors, etc.

Preparatory work

For the first and second layers, a white decorative clay plaster with a color pigment will be used.

Pour 8.5 L of water into a container of at least 35 L, add the entire 132_B color pigment and mix well with a dedicated electric mixer. While continuing to stir, slowly add the entire content of the package of white decorative clay plaster, mix well and allow the mixture to swell from 1 to 12 hours after covering the container. The mixture may look quite liquid, but it will thicken later. Stir the decorative clay plaster again before plastering.

Follow this link to learn how to prepare the mix correctly and how to plaster the first layer:

While the decorative clay plaster swells, adhesive protective strips should be used to protect adjacent walls, ceilings, floors, electrical switches and other details on the wall. At the same time, adhesive protective tape will help to form a nice inner corner, just note that when gluing the protective tape on an adjacent wall, it cannot be pasted directly into the corner – it is necessary to leave a gap of 1-2 mm between the strip and the inner corner, so that the clay plaster does not crumble after plastering the wall and peeling off the strip.

The clay plaster mixture can be applied with typical putty tools, but a stainless steel trowel with a handle from above should be used for pattern formation and polishing. The trowel should be flexible enough, not too hard. The edges and corners must be rounded so as not to leave cuts on the wall. Quality metal will ensure that the tool does not leave black marks on the wall. You will also need a smaller spatula to take the mixture out of the bucket and apply to the corners.

The first layer:

In the first layer, cover the entire area with decorative clay plaster and create a more prominent texture at intervals. All the created effects will be seen later in the last layer, so don’t overdo it, because the more different effects are created, the more variegated the wall will be. Analyze the surrounding architectural objects or try to intuitively feel how much, where and what strokes to make, and where to just leave a flat wall area.

You can also apply the clay plaster to the wall in a circular motion, if it is more convenient, but later you have to rub the entire surface again in a straight line horizontally and vertically with a trowel, so that there are no signs of rotational movements. After leveling the wall, clean the trowel with a spatula and swipe again over the surface of the plastered wall to accumulate a small excess of clay plaster mixture on the edge of the trowel, which forms a prominent texture. The forming movement must be as if out of inertia – fast and without much pressure on the wall. If this movement fails to create a natural-looking texture, you can stick the trowel to the wall in the full plane and get a slightly different texture pattern when you lift it. Cover the remaining wet clay mixture with a film or lid to prevent it from drying out. We recommend using the mixed mixture within two weeks.

Your wall will dry completely in about 10 – 14 hours. Then, with the edges of a spatula or trowel, lightly shave off the weakly adhering clay plaster and the most prominent areas of the created texture, but do not make them flat. It is best to shave the beginning and end of the stroke, thus creating a mountain effect and strokes that rise from the wall and disappear into it again.

If you want to create formwork effects on your concrete imitation wall, you have to form blocks of the desired dimensions on the dried first layer by gluing a 5 – 10 mm wide protective paint strip. For more expressive lines, glue the tape two or even three times on top of each other. You can use line bouncers or other measuring and marking devices to make the simulated blocks as smooth as possible.

The second layer

For the second layer of concrete imitation wall, the decorative clay plaster may not be as thick as in the first layer, therefore, you can add up to 0.5 l of water to the remaining mixture and mix well again.

In the second layer of concrete imitation wall, you have to thinly cover the entire wall area, only this time not creating a prominent texture, but vice versa, leaving some small cavities through which the first layer would be visible. Cavities occur naturally when clay plaster is applied to the wall in a very fast motion. Don’t try to create cavities artificially  as they won’t look nice and natural, so if you really can’t do this, don’t do them at all, just cover the wall with a thin layer of decorative clay plaster. Even if you get beautiful, natural-looking cavities – don’t overdo them, because the more of them there are, the more variegated the wall will look. Do not try to reproduce any effects symmetrically in any layer. Note that the painting strips must be covered with decorative clay plaster and better plastered in areas from one edge of the block to the other, this will make it easier to control the processes and, if necessary, stop.

The second layer of decorative clay plaster will dry in about 10 – 14 hours.

The third layer

You can now prepare the clay – marble putty FINISH NO. 9 for the third layer. Pour 6 L of water into a container of at least 20 L, add all the 134_B color pigment and mix well with a dedicated electric mixer. While continuing to stir, slowly add the entire content of the package of the clay – marble putty Finish No. 9, also add about 20 g of ground hardwood charcoal, which will give a very nice, black grain noise effect. Stir the mixture again and cover the container to swell from 1 to 12 hours. The mixture for the third layer should not be too thick as it will apply very thickly and may hide the second layer too much or even crack.

After the second layer of the wall has dried, peel off the protective paint strips from the wall, which formed an imitation of the formwork. Stir the mixture again and check that it is not too thick, because it should apply on the wall thinly and easily. Already after the first stroke, you can see how the effects created in the first two layers stand out, and how the grains of embedded carbon are revealed. When working with clay – marble putty FINISH No. 9, te most important thing is to remove the excess mixture with a trowel so that in places it is almost transparent. It is also possible to create natural-looking cavities in this layer, but we recommend doing just a few. In the third layer, interesting cavities can be obtained by putting a clean trowel all over the plane against the still wet wall and simply pulling it back. Often, these effects are quite unintentional, when you still want to repair already plastered wall areas. Therefore, keep in mind that it is better not to make major repairs on a slightly dry surface or to be very careful, as it is easiest to damage at this stage. As in the second layer, we recommend plastering from one edge of the block to the other.

Hardening

When the wall no longer sticks and no longer smears when touched by hand, but it is still wet – we can gently harden it with a trowel. It is difficult to say the exact time, as it all depends on many drying factors, but the approximate interval for the start of hardening is from 30 minutes to 1 hour. Hardening takes place with the same stainless steel trowel. The tool must be clean and dry, and the hardening itself takes place by slightly lifting one edge of the trowel from the wall, gently pressing the tool. The same area should be touched with the trowel no more than 1 – 3 times, in horizontal and vertical movements. If you harden the wall very intensively, it may crack during the drying process. However, for concrete imitation, this may not be a defect but an effect.

Effects of water runoff

Allow the third layer to dry a little more, and at the same time prepare a mixture of water and black pigment to create the effect of water runoff if you plan to do so. Add about 10 g of black pigment to 1 liter of water and mix well. Sprayers, brushes and rollers can be used to create a water runoff effect. The most beautiful effects of water runoff are obtained with the sprayer – slightly spray the mixture with the mist until the excess begins to flow naturally. If the flow is too bright, you can carefully spray the wall with clean water that will flush out the already existing drains. Do not make repetitions of the runoff effect on the entire wall and at one height level. Ideally, you should select just a few places for this. There is also one golden rule of “pouring” – be sure to destroy the beginning and end, and you can do this by spraying clean water or a damp sponge with tapping movements. You can also spray the entire wall area at intervals with pigmented water, but without making any runoff. Later, hardening the wall again can darken nicely in those areas, making it look more natural. But do not harden in any way if the surface of the wall is still shiny, and the wall itself is sticky and still smears your hands when touched, as you will displace the effects of touches. If the wall has dried in places to create the effects, it should be slightly moistened with clean water, wait until the water is completely absorbed, and the wall itself will not be smeared when touched by hand and then harden again. The more you harden, the more the wall will shine, so if you want a more matte wall, you can not harden a second time. If during the drying process you see that there are ugly darkened areas after pouring the pigmented water, tap them with a damp sponge with a strong motion, just do not rub in any way.

Impregnation

Allow the wall to dry well, this can take 12 to 24 hours. In order for the wall to acquire not only resistance to abrasion and liquids, but also richer, brighter colors, it can be covered with natural tung oil. When oiling, it is important to roll out the entire wall well, especially the roller connection lines. After soaking the roller, it is recommended to oil about 1 sq. M, then without soaking the roller, return again and roll well the already oiled area with a semi-dry roller, etc. At corners where it is difficult to oil with a roller, carefully apply the oil with a brush. Coating the wall with oil can provide additional effects by spraying plain water. Those areas that will receive water will lighten, because the water will displace the oil, so it is possible to create natural-looking whitish runoff effects or lighten the wall in places, to give more spots. After a few hours, when the oil absorbs and the wall becomes matte, it is recommended to clean the surface with a clean microfiber cloth to remove excess oil and dust from the clay mixture. Don’t be fooled by the first impression of a newly painted wall, the real effects will only be revealed within 24 hours and especially if water has been used.

Tung oil is better to cover those walls that will receive natural daylight, and only once, because in the dark, the oiled wall, especially in the presence of excess, can begin to turn yellow. Also, keep in mind that tung oil is a natural product that polymerizes naturally by reacting with oxygen, so even for a few months you can smell the oil, which is safe for your health. After trying this on your own, flaxseed and other oils can be used. If you like the color intensity and the existing result after the third layer has dried, you can glaze the wall or not cover anything and leave it naturally. For more information on wall impregnation methods, read our work manual on the website www.clay.lt

 

*All information provided is merely a guide. Mr. Clay cannot take responsibility for results that fall short of expectations. We will always be happy to advise and help you until you achieve your desired result.