Plastering the surface is the most effective way to prepare a base for a topcoat, as well as one of the options for decorative finishes. To give the plaster layer the desired texture, it must be processed, in other words, grout. The grouting process itself is simple, but it has its own subtleties and secrets, without which a quality result cannot be achieved.
Plaster grout - photo
Grout is the final stage of plastering work, which consists in eliminating the smallest errors, leveling and smoothing the surface by rubbing the dried mortar with a special tool. When using decorative plaster, the main purpose of grouting is to form a certain relief of the working plane.
Application of a finishing layer of finely dispersed leveling plaster
Before grouting, a "cover" is applied to the base - a finishing layer of plaster mortar. The base layer, or primer, is very durable and therefore difficult to process, while the cover layer ensures uniform filling of irregularities and maximum smoothness during grouting. The plaster is rubbed after the mortar has set, but until it dries completely.
Troweling the cover
Basically, for grouting plaster only one tool is used - a float, which is a rectangular cloth with a handle. Graters differ in size and material of manufacture, and, depending on this, are used for a certain type of work.
|Types of graters||Characteristics|
|Wooden trowel is suitable for cement and gypsum plaster, makes it possible to smooth the surface as much as possible and eliminate minor irregularities. You can make it yourself from a regular bar. At the same time, it has significant disadvantages - the wood is saturated with moisture, which complicates the work, the lower part is quickly erased, after drying, the canvas may deform|
|As a rule, plastic floats are used to spread the plaster mixture in small areas, followed by the formation of a smooth or embossed surface texture. Their use requires certain skills in plastering|
|Easy to use work, lightweight and durable. Characterized by low abrasion, suitable for all types of plasters|
| Available at a price, easy to use and light grater, but very short-lived. |
It is mainly used for final sanding of the plaster layer
|Working surface such graters are made of sponges of various densities, as well as latex and rubber.It is used to form a decorative texture on the surface, finishing smoothing|
|Metal graters are designed to compact the plaster layer, form a perfectly smooth base for painting|
Wooden plaster float
Tools for plaster
Preparation of the coating mortar
The coating solution is mixed in the same proportions as for the base layer:
Table - Proportions of the solution
The only difference is that the finest sand is used for covering, with the size grains no more than 1.5 mm.
Coarse sand is allowed only if the base is plastered under the tiles.
For high-quality grouting, the solution should have a normal fat content: lean mixtures do not have sufficient strength and crumble during surface treatment, and excessively fatty ones are poorly leveled, leaving stripes.
The mortar should adhere slightly to the spatula and be plastic
Tip. It is not difficult to determine the fat content of the plaster mortar: if it sticks strongly to the trowel, it is a greasy mortar, and you need to add sand, if it does not stick at all, this is a skinny mortar in which there is not enough cement. A normal solution mixes easily, has a homogeneous consistency, leaves an even thin mark on the trowel.
The sand is sieved through a sieve with a mesh size of not more than 1.
We sow sand for the solution
Pour cement into the mixing vessel, add sifted sand and mix dry. Next, pour in water in small portions to achieve the desired consistency.
Preparation of the batch
When mixing cement-lime mortar, the lime dough should also be filtered through a sieve.
The presence of even small grains will lead to the formation of marks on the surface, and it will not be possible to achieve perfect smoothness.
Filtered lime dough
Step 1. Plaster the surface is moistened with a spray. This increases the adhesion of the cover to the primer layer. It should be moistened evenly, without gaps and not too abundantly, so that the water does not flow from the wall in streams.
This should be done 15-20 minutes before applying the solution. If the working area is large, it should be divided into squares, and only the area that will be processed should be wetted.
The surface can be wetted with a brush, dipping it in water and splashing it on the wall
Step 2. For covering will need a trowel and a metal rule, or a wide spatula.
Rule for plaster
The solution is thrown in small portions on the wall, starting from the top, and then distributed over the entire plane using the rule.
The rule must be well pressed with your hands so that the solution clogs more densely into the slightest irregularities. Excess mixture should be removed. The thickness of this finishing layer should not exceed 2 mm.
Leveling the mortar
Step 3. When the cover grips slightly, take a grater and begin to rub the surface.
Some plasterers prefer to grout at the same time as the grout is applied.
Rubbing the wall with a float
There is no fundamental difference here, and this does not affect the result, the main thing is to grind the composition on a plane to eliminate unevenness. Let's take a closer look at both options.
So, if you decide to wait for the plaster to set, the grouting process is performed as follows: they take a polyurethane or metal float, moisten it with water, press it to the surface and in circular movements smooth out the plaster. You do not need to press hard on the grater - this way you can rip off the fresh solution and you will have to repair the scratches, but there is no point in rubbing too lightly.
Grouting the walls
Perform movements with equal force, slowly moving along the plane from top to bottom or horizontally. At the joints of the walls, apply the trowel parallel to the corners and rub in vertical movements, and not in a circle. Where elevations are noticeable, the tool is pressed more strongly, on the recesses, on the contrary, the pressure is reduced. The solution collects on the side of the grater during operation, so it must be periodically cleaned off.
Using a metal float
When grouting a large area, the cover may dry out quickly and become difficult to work with.
To soften the coating, it is periodically moistened with water. You can use a spray bottle or put a bucket of water next to it in advance and prepare a wide brush with long bristles. It is convenient to use the same brush to remove excess mortar from the grater.
If grouting is performed with the application of a solution, the procedure will be as follows: the solution is made a little thinner than the mixture for plaster, it is taken a little directly on the grater, applied the tool to the wall and with pressure distribute the composition along the plane. In this case, the grater must be held at an angle to the surface.
Having smeared the solution, press the float cloth against the wall and carefully rub everything in a circular or arched motion. Try to rub intensively, making even efforts, then smoothing is faster and better.
Grouting with mortar
This application requires very little mortar, and it takes a lot of grouting time, and it is better to mix it small portions to avoid solidification. When processing one plane, the intervals between grouting adjacent areas should be minimal - take a break only to prepare the solution. Moistening each subsequent square, slightly moisten the already rubbed edges - this will increase the adhesion of the solution and no transitions will be visible at the border of adjacent areas.
Surface treatment with circular motions is called "round" grout. This method allows you to well compact the plaster layer, get rid of all the bumps and depressions. But it still does not give ideal smoothness, since noticeable arcuate traces remain from the circular movements of the float. Of course, such a base is quite suitable for tiles or textured paint, but under ordinary paint these irregularities are clearly visible. Where the most smooth surface is required, it is necessary to grout in one more way - "run-through".
Methods of grouting
Trowelling must be done on wet plaster and immediately after grouting "round". Only if these conditions are met can an excellent result be achieved. A solution is no longer needed here, and humidification is performed only if necessary. Another important point is that the grater must be absolutely clean, even, with rounded edges. If the tool is not cleaned of solution, hardened chips will leave scratches on the plane, as will the sharp edges of the blade.
Plaster grouting - methods
For convenience, the surface is treated in small areas - about 1 m2. The grater is pressed against the wall and is driven up and down the plane with measured, precise movements. During grouting, try not to pull the tool away from the plaster, and maintain the same pressure at all times. Horizontal or circular movements are not allowed here - only vertical ones.
Smoothing the plaster mortar
Smoothing is final, but optional stage of grouting the surface.
Some master plasterers replace grout with them, but only if high quality factory plaster mixes are used. For smoothing, use a grater covered with felt or rubber, or metal. In general, the process resembles a "ramp-up" grout, only the surface is treated twice: the first time the movements are performed strictly vertically from top to bottom, the second circle - horizontally.
The process of smoothing the covering with trowels
The pattern of decorative plaster is formed in two ways - when applying and after setting the solution.In the first case, smooth floats are used for grouting, allowing to remove sharp protrusions on the surface and soften the relief of the pattern; in the second, both smooth and textured floats can be used, depending on the composition of the plaster.
A solution is applied to the prepared base with a spatula or trowel, making strokes in a certain order or randomly. You do not need to level and smooth anything, the main thing is that the layer of plaster lays down approximately the same layer over the entire area, and there are no missing areas. After application, you need to wait 20 minutes for the solution to set so as not to stick to the instrument. Next, they take a grater, moisten it with water, apply the canvas to the surface and, with light pressure, very carefully perform movements in one direction.
Move in one direction
If you press too hard, the plaster will smooth out and the pattern will be blurred. And so only sharp protrusions will be smoothed out, the depressions will acquire a slightly more rounded shape. Periodically, the grater should be moistened for easier glide.
Grouting decorative plaster
The plaster is applied in a layer of 2-3 mm and carefully spread over the plane with a metal spatula or a rule.
The surface should be as flat as possible, without traces of a spatula, transitions and other defects. Let the solution dry a little (15-20 minutes), and start grouting. It is more convenient to use a plastic float here. Grouting is performed in strips no more than 1.5 m wide.
Movements can be circular, vertical, horizontal, oblique and even zigzag, but always in one direction. Only in this way a clear pattern will appear on the surface.
Perform movements in one direction
Be sure to moisten the grater, and periodically clean it from adhered plaster during work - its particles fall into grooves and smear the pattern. Perform movements carefully, trying not to cling to the already passed sections. After finishing one strip, immediately start rubbing the next one.
So that no transitions are visible between the stripes, moisten the joints well with water. Avoid interruptions in work, as the plaster dries quickly and it will be impossible to form the desired pattern.
After finishing grouting, wait until the surface is completely dry and treat the walls with a foam float. Such grinding will give the coating smoothness, remove excess particles of the solution, and at the same time will not damage the pattern at all.
Posted By: Work Style |05, Nov 2020
Posted By: Work Style |05, Nov 2020
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Posted By: Work Style |10, Nov 2020
Posted By: Work Style |05, Nov 2020