Finishing plaster, what it is
First of all you should know that the finish plaster depends first of all not on the composition, but on the consistency and dispersion. Even if you work with a cement-sand mix, the finishing layer will contain the same components as the roughing. However, still the plaster solutions for the final finishing are quite different, if we talk about the main components. In other words, there are finely dispersed mixtures of cement-sand, cement-lime, gypsum and acrylic-polymer.
Many prefer to use sandblast mixes for final finishing, however, any specialist will say that is the best adhesion between plaster layers of the same composition .As an exception, it is possible to apply the mixture with components other than those contained in the previous layer, provided that the basis is a stronger compound. However, the rough primer under the plaster of finish finish can be any, and on top of it the decorative acrylic-polymer plaster will perfectly lie.
Since it is not always possible to use two plasters of different composition( rough and finish), it will be useful to know that the composition of the "clean" covering( the smoothest layer) contains the same components as in the spray with the soil( the first two layers), howeverwith minor changes. So, for example, in cement-sand plaster the final stage will be applying a solution with very fine sand. Cement-lime mortar for finishing should contain more lime than for previous layers, to increase the plasticity of the mixture.
The finishing compound always contains the finest grained components, which makes it possible to create a perfectly smooth surface.
Finishing plastering of walls in the standard way
You probably know that the very first layer of plaster( spray) is performed by a solution, the consistency of which resembles sour cream, that is, it is liquid enough to literally spit the mixture on the walls. The second layer, which is called the soil, is the most solid, it is more like a liquid dough and it is applied by the buster without much effort to give it smoothness; on the contrary, it is the rough texture that will allow the final finishing coat to be firmly laid down. If the thickness of the first layer does not exceed 3-4 millimeters, and the second should not be thicker than one and a half centimeters, the covering is thinner, the better. Ideally, this layer should be in 1, maximum - 3 millimeters.
For the final finishing phase, prepare two spatulas, narrow and wide. The first solution is scooped from the container, say, from a bucket, although it is much more convenient to use a wide tray with low sides, and a second spatula, wide, the mixture is applied to the walls. The movement of the wide spatula should be continuous, from the bottom up, the wider the trajectory of the spatula, the smoother the plaster layer will be. Remember, because of the high density of adherence, the finishing plaster of the walls on the roughing layer is always final and can not be removed, it can only be ground after the final drying. By the way, machine plaster is always more even, and, often, does not require grinding.
Flexible plasters as a special variant of external wall finishing
The house has to be finished not only from the inside, but also from the outside, and plastering is sometimes the most optimal option, taking into account the climatic factor. The external surfaces of the walls are subjected to numerous tests not only on the side of precipitation, the constant influence of winds and the sun is an uninterrupted inspection of the plaster for strength. And very often the finish surrenders, covering with cracks and eventually collapsing. However, since recent time, elastic facade plaster has become widely available on the market, the use of which substantially extends the service life of the exterior finish. The composition of this plaster is acrylic, a polymer that gives it an amazing plasticity.
Tightly adhering to the black layer, the elastic plaster covers it like a rubber film and, in the case of an increase in stress on any part of the wall, the finish layer simply slightly stretches, whereas in any other case a crack would appear. Given that this material has a water-dispersion basis, the solution is applied very simply, and with the correct consistency there will not be any spray around. Otherwise, the method of application does not differ from the work with ordinary gypsum plaster - the spatula should be kept at an acute angle to the surface, tightly pressing, literally rubbing the composition into the rough surface. With continuous movements of the tool, an even layer will be guaranteed, but avoid missing even the smallest section of the wall, it is in this place in the future that the elastic plaster will give slack.
