All plaster mixes for outdoor use must meet two main criteria: have high strength and durability. In most cases, the plastered facades of buildings are subsequently covered with various finishing materials. But there are also options for using plaster as a topcoat. In such cases, they can be made according to special recipes that allow you to get the original appearance of the facade walls without additional finishing.
Plaster mixes for outdoor use
Decorative plaster and its shades
Currently, manufacturers of building materials offer developers a huge range of dry plaster mixes, it is possible to choose the best option.
Due to innovative additives, the mixtures have excellent performance indicators, can be used on all types of buildings, etc. But they all have two drawbacks.
But when finishing a large cottage, the difference in price reaches several tens of thousands of rubles.
It is convenient to use ready-made mixtures, but the difference in price, when compared with home-made mixture, is noticeable
At any construction site there is always cement and sand, it is needed not only for the manufacture of plaster, but also for masonry. Even for wooden houses, sand is needed; concrete for foundations is made from it. This means that you can make the mixture yourself without any problems. It only takes desire and skill.
Making plaster mortar with your own hands
Depending on the condition of the walls, the thickness of the plaster layer may exceed 3 cm, which is essential increases the demand for materials.
This is another reason not to use purchased materials.
Professionals consider it advisable to use store mixes only in a few cases:
For finishing leveling, factory mixes are used
The same requirements are put forward for the materials used for plastering the operated basements. It is almost impossible to make such a plaster on your own; all components are not available in free implementation.
Hydrophobic sanitizing plaster
If you use an ordinary mixture, then in the future it must be impregnated with waterproofing compounds or covered with roll based bitumen. This requires additional waste of time and money;
In addition, there is no way to make two batches completely identical, industrial lines dose components much more accurately. And then in different parties you can notice minor differences. What can we say about manual work.
The composition of plaster mixes for external work is selected taking into account their specific place of use. We will tell you about the most commonly used cement-based materials.
But there are cases when the restoration of old buildings is carried out, in ancient times original mixtures were used, today they are almost never used. They do not have high performance by modern standards, but knowledge of the recipe can come in handy. In this regard, we will try to give the maximum list of materials.
|Composition||Characteristics and use|
Cement + sand
| For plastering external surfaces, you need to take three parts of sand for one part of cement grade M400. Depending on the condition of the surfaces, the amount of sand can be slightly increased or decreased.
If the walls are very uneven and it is necessary to apply a lot of plaster in several layers, then for the first one should make a "greasy" solution, and for the finishing one the amount of cement should be slightly reduced. The "greasy" solution has improved adhesion to the wall, which eliminates the likelihood of delamination, and the "lean" mass gives fewer cracks during solidification of a thick layer. For the preparation of decorative solutions, stone chips, mineral dyes and special fillers can be added to the mass. We will describe how to do this a little below. The cement mortar is suitable for universal use.
Cement + lime + sand
| The composition includes three parts of sand and one part of cement and lime. Due to the presence of lime on the surface of the walls, fungi and mosses do not grow, the solution has a bactericidal effect. The lime is preliminarily slaked.Such compositions are used in Eastern Europe for both external and internal work. In terms of physical characteristics, it is slightly inferior to cement-sand mixtures, but surpasses them in operational characteristics.
In addition, due to the use of lime, the cost of the material is reduced.
Clay + sand
|Currently, very rarely and mainly for the restoration of old buildings in some southern regions of our country. To reduce thermal conductivity, chopped straw is added to the solution.|
Regardless of the composition, there are several general recommendations for all mixtures.
If it contains clay, then the amount of cement should be increased.
The solution should not delaminate
It is desirable that the sand is dry. Cement absorbs liquids very little; to increase its density, it will have to be added a lot.
Sand should be added to the slurry, and then the composition should be mixed
The disadvantage is the increase in cost and the greater likelihood of cracking during solidification.
Greasy cement mortar
Only a small amount of plaster can be prepared with a construction mixer
If you want to prepare multi-colored plaster with the addition of mineral dyes, then you definitely need to buy white cement. True, if a bag of 50 kg of an ordinary one costs within 200 rubles, then the price of white is about 500 rubles for the same bag.
White Portland cement
Practical advice. There is a way to make the recipe for making colored plaster even cheaper. Do not add dyes, but select the color by using various sands.
Depending on the location of the quarry, it can be from white to yellow or grayish. Accordingly, the plaster will be of the same color. By the way, sand never burns out, even the most expensive mineral dyes cannot be compared with it in color stability. Of course, white cement is needed.
Some shades of sand
For example, we will consider the option of manual preparation of plaster like "bark beetle".
For facade wall decoration, this is one of the most acceptable and beautiful options.
The texture of the plaster "bark beetle"
Step 1. Prepare the place and tools for mixing. You can knead on a ready-made flat concrete base, if not, then use pieces of sheet iron. To work, you need a shovel and a water container.
Step 2. Prepare materials. Due to the fact that we make "bark beetle" plaster, there is no need to sift the sand. The mortar is prepared in the following proportions: cement - one part, sand - three parts, stone chips - one part.
If you need a lot of mortar for work, store the materials in the immediate vicinity of the place of mixing.
Step 3. Scatter sand on top of the pile, add stone chips and cement on top. Nobody measures the material with buckets, consider it as shovels. For kneading, you need to have shovels.
Organize your workplace correctly, this will greatly speed up and facilitate the mixing process. It is better to throw a bag of cement on a large pile of sand, cut the package in half with a shovel and take it straight from the halves of the bag. Do not worry that he will wake up a little, then pick him up with the sand.
Keep in mind that one 50 kg bag of cement produces approximately 0.25 m3 of mortar.
One bag contains approximately 15 medium shovels. This knowledge will make it easier for you to calculate when mixing the solution. This means that about 45 shovels of sand and 10-15 shovels of stone chips should be taken for a bag of cement. It is quite difficult to manually prepare such a large batch; practitioners recommend using half a bag of cement at a time. The amount of sand and crumbs is proportionally reduced.
Water is a little more difficult, its volume largely depends on the moisture content of the sand. If you have it in an open area and got caught in the rain, then the amount of water may decrease by a third. It is impossible to give exact recommendations, determine the need as you prepare the batch. To begin with, pour about 4 buckets into half a bag of cement, then orient yourself as you work.
Transfer the pile of material first to one place and then back to the center of the platform. If its size does not allow you to transfer the entire quantity at once, then divide it into two parts. During the tossing, the components are not mixed very thoroughly, but this is not a problem. Subsequently, the ingredients are distributed evenly throughout the volume.
Make a hole in the middle of the pile, it should be quite large. Make sure that there is always a roller of dry mortar around, it should not allow water to flow out during mixing.
Step 6. Pour water into the hole and start mixing.
Pouring in water
To do this, gradually mix the dry mixture with water in small portions and turn it over with a shovel.
Move in a circle, the dimensions of the protective shaft should always be approximately the same along the entire perimeter of the hole. Sand with cement can be taken both from the middle of the hole and from the edges. The main thing is not to make a hole through which water will escape. If the solution is thick, add a little water.
Well with water in the center
When the dry mix becomes small, speed up the stirring ... Cover areas with very thin solution with dry sand and stir immediately.
It is not necessary to achieve one hundred percent homogeneity, additional mixing will occur during the collection of the solution into the container before plastering and during plastering of surfaces.
Practical advice. In order to find out exactly how much stone chips are needed, it is recommended to make a small trial batch. Then plaster a small section of the wall with the solution made and make a pattern. If there are few "bark beetle moves" - add crumb.
This material is very popular lately due to the desire of home owners to reduce heat loss.
To reduce the thermal conductivity indices, not ordinary sand should be added to the solution, but a perlite filler.
One part of cement can be given 5 parts of filler, if you need to make the mass more durable, then increase the amount cement. Water, as always, is added as needed.
Important. When working with dry perlite, use protective masks.
Many builders ignore this requirement, but in vain.
Step 1. Measure out the required amount of perlite. This is a rather expensive material, do not overspend. It is recommended to first find out the entire volume required for one batch and prepare one large container for it.
In the future, make a small hole in the plastic bag and carefully fill it. Avoid heavy dusting, keep the bag as low as possible above the container.
Step 2. Turn on the concrete mixer and add water.
Pouring water into the concrete mixer
It is advisable to pre-measure its amount.
The fact is that this filler absorbs much more water than sand. If you need to prepare a large amount of a solution, then all the proportions of the ingredients for one batch must be memorized and not experimented every time.
Step 3. Add a special soaping resin to the water, if it is not there, then liquid soap will do at the rate of about 100-150 ml for a concrete mixer with a volume of 0.25 m3.
Dilute the soap a little with water, you need to foam it. Water needs about 2.5 buckets. Do not pour any more, otherwise the perlite will rise up and not get wet.
Use liquid soap or lathering resin
Never pour completely dry perlite into a concrete mixer, first wet it in a container. To do this, pour water into it, add perlite and stir with a shovel until you get a mushy state. The mass is considered ready after the perlite stops dusting with stirring.
Step 4. Throw wet perlite into a concrete mixer¸ if it sticks to the walls, add water.
Master picks up wet perlite with a bucket
Throwing perlite into the concrete mixer
Only a little, otherwise problems will arise - the excess cannot be removed by adding perlite. The fact is that dry perlite will float from above and will not be able to absorb moisture. You will have to stir it again by hand and only then add it to the mixer.
Step 5. Once the pearlite is homogeneous, start adding cement.
Sprinkle it in small portions, do not allow the formation of balls. It is very difficult to get rid of them later. If you plan to use the mortar for plastering some wall surfaces, then increase the amount of cement. Constantly monitor the consistency, add water as needed.
Practice shows that, despite all efforts, it is not possible to completely avoid adhesion of perlite with cement to the walls of a concrete mixer .
.. It is necessary to stop the concrete mixer, carefully clean the walls of adhering material with a trowel and mix it a little with the ready-made one inside the barrel.
Step 6. In the last step of mixing, add sand.
Increase the angle of inclination as the mixer fills. Keep in mind that the larger the angle of inclination, the worse the mixing process will be.
If the mixture sticks to the walls again, you need to periodically stop the mixer and clean its walls. There are situations when the mass in the middle of the mixer volume is normal, and on the sides it is liquid. Stop the mechanism, select two or three buckets of mass from the middle, tilt the mixer and turn it on again.
In this position, the mass mixes better. Everything is fine - add the removed mass again, tilt the mixer and turn on the engine.
Stirring the mortar
Such a mortar is more difficult to prepare than an ordinary cement-sandy one, this must be understood and not be afraid of the first difficulties. Some professionals advise adding slaked lime to the solution, we consider this an optional condition. The fact is that perlite itself inhibits the development of microflora and additional ingredients are not required.
But the final decision is yours. There is a desire and opportunity - add lime.
First, you need to tell how the mortar mixer differs from the concrete mixer.
The main element is a rotating drum, to the walls of which blades welded.
Homemade concrete mixer
Advantages - versatility.
Concrete and sand mortars can be prepared in a concrete mixer.
Disadvantage - the quality of mixing does not always meet the required parameters. To improve, you have to significantly lengthen the process. Another disadvantage of a concrete mixer. During the preparation of the solution, as the container is filled, it must be constantly raised (reduce the angle of inclination), and the principle of operation of the unit is such that the greater the angle of inclination, the better the solution is mixed.
Accordingly, if a lot of mortar needs to be prepared in one batch, then the concrete mixer must be partially released periodically, the angle must be increased and the remaining solution must be mixed. It takes time and effort. Mortar mixers have no such disadvantage.
The body has the shape of a circle and stands motionless. The blades rotate inside the body.
The advantage is excellent mixing quality, lumps of cement and sand are completely broken. The disadvantage is that concrete cannot be prepared in a mortar mixer. The fact is that large fractions of crushed stone fall into the gap between the rotating blades and the fixed bottom. The mechanism gets stuck, which causes the electric motor to burn out.
Mortar mixer from the barrel
All mechanisms are first poured water, and only then dry materials are added.
The cement should only be poured into water or a very thin solution. If you do not do this, then balls will roll in the concrete mixer, it is almost impossible to completely break them. This does not apply to the mortar mixer, it does not create such problems.
After finishing work, it is imperative to thoroughly wash the units. It is strictly forbidden to beat off the hardened solution with a sledgehammer or crowbar.
During such procedures, irregularities appear on the body, and then an increased amount of mass will accumulate in them. Negative processes are developing incrementally.
When connecting the equipment, unconditionally observe the requirements of the PUE, you work in constant contact with water, which at times increases the risk of electric shock.
Never try to clean the surfaces of the agitators while they are rotating, this will cause very serious injury.
It is important to wash the concrete mixer in time, observing safety rules
We have told only two recipes for preparing mixtures for outdoor work.
If you master them, then any changes in the recipe and technology will not be difficult.
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