Everything you need to know about shaving internal or external walls: what it consists of, how to do it, what tools are needed and what methods must be followed.
The definition of wall smoothing is intended to indicate a particular operation that has the purpose of leveling the walls, preparing them for subsequent painting, and obviously it is a procedure that can be performed both on the internal and external walls.
But what exactly does this operation consist of? Which products are used and what are the differences between the smoothing of the internal walls and that of the external walls? We therefore try to answer these questions as clearly and comprehensively as possible.
What is it and what is it for
The shaving is nothing more than the surface of a wall finish, thus represents the final stage of a preparation process which is essential before proceeding to the next painting.
In other words, it serves to complete the plaster and make it uniform and smooth to the touch, free from imperfections and well leveled; Furthermore, depending on the state of the walls, the smoothing is not always carried out on the entire surface but can be limited only to certain areas that may be more or less damaged than the rest of the wall.
Attention because it is absolutely not to be confused with grouting, the difference between grout and smoothing compound is that the plaster for walls is applied only where there are holes, cracks or other imperfections, with the aim of rectifying them and leveling the surfaces; the smoothing compound for walls , on the other hand, is applied to the entire surface of the wall after grouting.
The various stages of the operation
Before skimming the walls, it is necessary to carefully check that the plaster does not have air bubbles, cracks or small holes, which actually happens punctually in most cases. These imperfections need to be rectified; in the case of virgin walls, therefore, the first thing to do is to putty the wall ; as mentioned in the previous paragraph, that is, it is necessary to make sure that all the holes and any other imperfections present are filled with putty or with a specific paste for walls.
Once this phase has been completed, it is necessary to allow at least six or eight hours to pass, to allow the grout to dry well, after which the areas where it has been applied must be sanded to bring them level with the plaster layer.
The difference between plaster and smoothing , therefore, lies in the fact that the former is a preliminary coating that is applied to the wall in several layers to protect the masonry; smoothing, on the other hand, is the application of a finishing layer to complete the plaster, with the aim of perfectly leveling the surface of the wall and forming a “base” where the paint can take root more easily. In certain cases the plaster can also take on an aesthetic function; for example as in the case of “whitewashed” walls, on which the last layer of plaster that is applied is a finishing smoothing compound.
To smooth already painted walls , however, before rectifying imperfections with putty, you must first remove the old paint, to prevent the lower layers from fragmenting and detaching from the wall over time. Removal can be done in various ways; for example it is possible to wet the paint with a mixture of water and caustic soda and wait until the first bubbles begin to form and the paint begins to detach from the wall, thus making it easier to remove it with the aid of a spatula. steel.
A faster method, however, consists in the use of power tools such as belt sanders ; if the paint must also be removed from the ceilings, then the fastest and most effective way is to use a wall sander directly . After completing the grouting and smoothing phases, you can then move on to smoothing the walls by applying the appropriate products; subsequently then, before applying the paint, depending on the case, it may be necessary to apply one or two coats of primer, or of clinging agent.
Products for shaving
As previously mentioned, the actual smoothing is nothing more than the final phase of a process that begins with the application of the plaster and the subsequent smoothing and leveling of the walls, and then ends with the application of the smoothing compound. The term smoothing agent indicates two different materials, which in any case fall within the category of plasters but which are characterized by a much finer consistency; there are two materials: slaked lime and smoothing plasters.
The first consists of lime hydroxide and water, a mixture usually used as a binder in the preparation of mortars but which is also used as a finishing layer of the plaster. The smoothing plasters, on the other hand, are premixed and differ according to the intended use which can be internal or external.
As for indoor use, for example, one of the most popular products is Rasocote 5 Plus Activ’Air produced by the Gyproc brand, which in turn belongs to the well-known Saint-Gobain industrial group, leader in the production of materials for ‘building. In addition to plasters, there are also smoothing stuccos; these are available both in powder form to be mixed with water before use, and in paste to be applied directly. Smoothing fillers are especially suitable for finishing plasterboard walls.
For obvious reasons, external shaving is performed with different products compared to the one done on the internal walls; the latter, in fact, are not exposed to bad weather or atmospheric agents, which is why they can be treated with gypsum-based plasters, which are usually less resistant to water.
The situation changes completely for the external walls instead; for these it is necessary to use products that allow to obtain a water-proof wall and greater resistance to flaking. Therefore, for exterior smoothing, lime-based or even cement-based smoothing plasters are mainly used, in order to ensure greater resistance and durability.