Plaster is associated with the simplest types of finishing materials, which are distinguished by their affordable cost and ease of application. The very technique of facing surfaces with stucco coatings is characterized by versatility, which allows it to be used in both professional and domestic repair activities. Nevertheless, the requirements for decoration are constantly increasing, affecting the technical and aesthetic aspects of the design of the walls. Therefore, on the market are increasingly found compounds whose individual properties have been modified with additional ingredients. So there was an improved plaster, which stands out against the general background not only in composition, but also in styling technology.
What is the advantage of improved plaster?
In most cases, even simple plastering , provided that it is applied in good quality, fully fulfills its functions over a long period of operation. Nevertheless, improved formulations can eliminate a number of technical and physical drawbacks of conventional solutions. First of all, it is mechanical stability, which implies a high threshold of tolerance of the structure to the formation of microcracks, increased sealing, wider possibilities of mesh reinforcement, as well as the absence of destructive processes in contact with moisture. Modern technology of improved plaster also focuses on preserving the coating in special conditions of use. It has already been noted that such compositions are not afraid of moisture, but this does not mean that any improved solution can be used in the kitchen and in the bathroom. For such tasks, there are special modified mixtures, which also belong to improved ones. The universal modification is fire resistance. In relation to conventional plaster, such mixtures have a long period of preservation of the structure under direct thermal exposure and do not contribute to the spread of fire.
The composition of the improved mixtures
To begin with, it is worth saying that coatings made from traditional compositions without modifiers are also called improved plaster. Only three components are used to prepare such mixtures - sand, water and cement. And they are called improved only because of the special styling technique, which will be discussed below. The normative composition of the improved plaster without fail provides for the introduction of PVA glue, which acts as an additional binder between the cement base and sand. More importantly, the base components must be of high quality. Suitable sand, for example, is mined from the ground and not washed in rivers. The second option is cheaper, but in this case you can’t get a real improved composition. Also, cement should not be stale in cold and wet warehouses, but dry and ready to use - it is recommended to use Portland cement M400 or M500.
Solution preparation
There are also features in the procedure for preparing the solution. So, if simple mixtures are prepared using four parts of sand per one part of cement, then in improved solutions the ratio will be 3: 1. An increase in the amount of sand fractions, however, is allowed when adding quicklime to the solution . PVA glue should be used at the rate of 200 g per 20 liters of water. With the formation of a water-glue solution, you should start cooking by stirring it thoroughly. Next, a dry base with cement and sand is already being introduced. After thorough mixing with a construction mixer, an improved plaster with high elasticity and ductility characteristics should be obtained. In some ways, it will resemble molten rubber, but after drying this effect will pass and a tenacious coating with a strong structure will remain.
Features of gypsum compounds
One of the varieties of improved plaster mixes, which is obtained by modifying the basic set of components. As the name implies, this is achieved through the introduction of gypsum. First, the already described procedure for creating an adhesive solution is performed, after which gypsum is added to the dry mixture of sand and cement. The volume of this additive may vary, but in any case, the following rule holds: the mass of gypsum filler replaces only part of the mass of cement, but not sand. That is, 20-30% can be excluded from the usual proportion of cement, compensating for the lack of gypsum. If you plan to perform improved plaster with minimal cost, but without much loss in quality, then you can use just such a combination. Gypsum interacts optimally with PVA, so the displacement of cement will not be so noticeable in terms of the technical qualities of the coating, as in the case of conventional solutions.
Preparatory work before application
The solution can only be applied on durable surfaces, the bases of which do not have collapsing areas. To do this, it is necessary to previously clean the old peeling or weak coatings, primers and coatings. Next, vertical deviations are checked, that is, the fossa. It is desirable that the target surface has no deviations greater than 2 mm in height. A mandatory step in the preparation is spray. This is a kind of priming method for the site on which improved plaster with an adhesive base will be applied. The spray solution itself is prepared from soap and water. In fact, this is soapy water, which should easily moisten the work surface before laying the plaster. In this case, the spray should not leave individual places dry. It is necessary to fill small cracks and pits, so the presence of such defects in open form can create a risk for the destruction of a new coating.
Improved stucco device
Laying is carried out in two stages - through the implementation of the base and coverings. The base is applied as a primer. To apply the mass, you can use a grater, performing circular movements at an angle of 150 degrees relative to the working surface. The thickness of the base coat is 15-20 mm. As for the cover, to some extent this is the finish layer, during which accuracy is especially important. This layer will have a height of about 10 mm, that is, the total thickness of the improved plaster will be 25-30 mm. Coating is done with a grater, brush or trowel. The high responsibility of this stage is due to the fact that the contractor will have to be in time to do the grouting in time with the coating leveling. For this, a pneumatic bucket can be used - a mechanized tool for high-quality laying of plaster mixtures.
Where is it advisable to apply improved plaster?
The improved mortar for plaster, with all its advantages, has a number of limitations on its use. Firstly, the mixture is more expensive due to the use of the main components of high quality and the introduction of an adhesive ingredient, not to mention the possible auxiliary modifiers. Secondly, the presence of PVA glue, in addition to the positive effect, gives a negative one - the environmental friendliness of the composition decreases, which is an obstacle to the use of solutions in children's rooms, bedrooms, etc. Therefore, such mixtures for outdoor decoration can be recommended to ordinary home craftsmen. The best option would be improved wall plastering of the facade. The performance characteristics of the composition will protect the house from climatic influences, as well as protect the foundation of a brick or concrete surface from mechanical damage.
Conclusion
As can be seen, improved mixtures can be called only with some reservations. Therefore, before deciding to switch to this type of finish, you should think about why it is impossible to use conventional coatings. In addition, improved stucco in a broader sense may represent improved solutions in the base component. Other natural ingredients can be used to enhance a particular performance. Professional plasterers, in particular, regularly experiment with the addition of the same lime and gypsum in different proportions.