Plastering walls with cement mortar according to technology
Probably, in the modern world there is no person who at least once in his life does not encounter such a "natural disaster" as the repair of his home. Plastering the walls with cement mortar with your own hands is done quite often. This is the most common option for leveling and wall decoration.
Today we will tell you how the composition of the cement mortar for plastering the walls is made and describe the rules for performing this work. Also on the video in this article you can see a lot of the necessary information and do it yourself.
The content of the article
Rules for plastering
Plastering is not difficult if you adhere to the correct sequence of work. After all, there is a howl instruction, which is time-tested.
The price of the material is not high and everyone can afford this option. Many people wonder if it is possible to plaster aerated concrete with cement mortar (see Stucco for cellular concrete: how to choose), of course you can. Just a plane preparation system will be a little different.
Preparatory stage
Not only old, but also newly built walls need a preparatory stage before their plastering. In this case, you need to prepare all the walls, regardless of what they are built from. The meaning of the preparatory stage is that the plaster lasts as long as possible.
Preparation of walls from ordinary and facing bricks
The recently erected ordinary brick wall almost does not need a preparatory stage. In order not to impose too much plaster layer, with an ax it is necessary to remove all large irregularities.
But still you must first check the evenness of the wall. Then you will immediately see how the foundation is made.
So:
- First you need to pull the line diagonally along the diagonal. Then you will immediately see deviations from the plane and determine the desired layer.
- If the layer is less than 2 cm, then it will be possible not to do the alignment. It’s even possible to do work without reinforcing mesh.
- If the layer is over 5 cm, then it is worth leveling the wall before plastering. Quite often, drywall is used for this.
Caution: The brick wall must be sufficiently moist, otherwise the cement mixture will slip down.
There is a common opinion that it is better not to plaster a facing brick. But sometimes you want to do something new, for example, lay a wall with tiles. To do this, it must first be plastered (see Let's consider how to plaster a brick wall) To do this, you have to make a little more effort.
There are several solutions to this problem:
- The most popular is wall battens. There is nothing complicated in its manufacture. To do this, the aluminum wire is wound on nails driven into the seams between the bricks.
- If the wall area is not large, then using a notched trowel, tile adhesive is applied on its surface in a small layer. After a day, you can plaster the wall.
- The best solution is a stucco mesh fixed to the wall. We must not forget that the brick surface must be treated with a primer.
| Concrete wall preparation process | Concrete blocks, like facing bricks, are difficult to plaster. Here you can also resort to the help of glue or mesh. |
| Work on the preparation of walls from cinder blocks | With cinder block walls, everything is much simpler. For stronger bonding of the plaster to the surface, they need only sufficient moisture. |
| Preparatory stage for shell wall | Wall preparation from a shell rock occurs similarly to cinder-concrete walls. They need only plentiful hydration. |
| Preparatory work for a wooden wall | To prepare a wooden wall, it should be primed and fixed on it a plaster grid. |
| Preparatory work for drywall walls | Very often there is a need to plaster gypsum plasterboard surfaces. Most often these are walls in the bathroom. Here you can do only with a primer on the surface of the walls. |
| Preparatory work for walls made of different materials | Very often you can encounter a situation when the walls are built of materials of various kinds. Often there are partially brick walls, partially limestone walls, etc. In some cases, the depth of the bumps can be up to 20 centimeters. To begin with, the wall should be primed and the stucco mesh fixed on it. The next step involves leveling the walls with cement. Work can be continued after the plaster has completely hardened. |
Preparatory work for plastered walls
Everyone who has faced the preparation of walls that were previously exposed to plaster, agree that this is one of the most difficult tasks.
Attention: The difficulty is that first of all you must get rid of the old plaster. She must be repulsed, even if this activity is not pleasing. Only after the end of this procedure do they begin the stage of preparing the walls.
- Plain cement plaster does not cause much trouble, it easily leaves in large layers. Much more effort will have to be made to remove the plaster from the cement mortar. Somewhere it is easily separated in large pieces, and somewhere it is difficult to beat it off even with a puncher. But no matter how difficult it was, the old plaster will have to be removed. After all, it will cause great inconvenience and prevent the application of a new plaster layer.
- But, by right, the most difficult is the removal of paint from a concrete wall. But even in our time of high technology, there is only one proven method - any sharp instrument and a reserve of patience. Where the paint holds most firmly, it is beaten off with a small hatchet. Undoubtedly, this is a complex and monotonous process that requires tremendous effort, but it must be completed.
- If you have a cement-lime plaster mortar, then it should also be removed. Some say that this is not necessary, but in this case, adhesion of surfaces will be minimal. Therefore, you have to clear the plane.
Reinforcing mesh and how to install it
To obtain a stable and flexible plaster on the wall, it is recommended to install a plaster or reinforcing mesh. It prevents the appearance of cracks formed when the plaster dries and as a result of the shrinkage of the building. The mesh helps to increase the mechanical strength of the plaster coating. The most preferred cell size is considered to be a parameter of 20 * 20 mm.
- A good reinforcing mesh necessarily has a special coating against corrosion.
- To fix the metal plaster grid, it is necessary to hammer metal dowels into the wall in a checkerboard arrangement. The distance between them should be equal to 30-40 centimeters. Next, with a special scissors, cut a piece of reinforcing mesh of the desired size.
- Mount the metal mesh correctly from the bottom up.The stucco mesh, due to its elastic properties, is quite easily fixed to dowels driven into the wall and fits snugly onto the surface to be treated. The next step involves wrapping a special knitting wire on top of the mesh. It should be wound on the dowels, repeating the outlines of the letter Z.
- You can also use pieces of lighthouses. In this case, two people must spread the reinforcing mesh on the wall, and another fixes the dowel with nails, on which particles of the lighthouse are put on in advance.
- For the correct joining of two parts of the grid, they need to be positioned by slightly letting the edge of one part of the grid onto the other part of it. This is necessary to ensure the integrity of the strengthening of the plaster and increase its resistance to mechanical damage.
Guide beacons and their installation
From childhood, everyone knows what a lighthouse is and what its purpose is. But not everyone knows the significance of lighthouses in repair activities. Meanwhile, this is a very important component, serving as a guideline for the implementation of plastering.
So:
- Lighthouses in construction are fixed points mounted on the wall using a level. Often they are made from nails, slats or from dried up tubercles of cement mortar applied to the wall. But construction professionals consider perforated metal profiles to be the best beacons. They can be easily purchased at all hardware stores. They are called very simply - beacons.
- Lighthouses are made by manufacturers of different thicknesses. They should be selected based on the thickness of the future layer of plaster. It is also important when choosing beacons to consider the stiffness of the profile.
The thicker the beacon, the harder it is.
There are two options for attaching lighthouses:
- Dots of cement, putty or tile glue are vertically thrown on the surface of the wall. We fix a perforated beacon on them. Using the construction level, it is leveled. If the length of the level is not sufficient, then a rule should be applied to the lighthouse, and the level should already be applied to it.
- Holes about 10 millimeters in size are clearly drilled vertically, according to the markings on the wall. Cone-shaped wooden bald spots are clogged in them. This shape is very convenient for screwing on beacons.
- Using a thread stretched between the upper and lower lighthouse elements, expose the entire row of flaps.
- Align them with an ordinary hammer or a hacksaw for metal. Then, on a set of wooden plaques installed in a row, the beacon profiles are mounted with screws.
- The areas between the flaps should be filled with cement mortar. This installation method is excellent for walls with significant irregularities.
- The first method in this situation is not effective, since these walls can not hold a large amount of mortar. The interval between the beacons is recommended to be made less than the length of the rule by about 10 centimeters.
- In the first version of the installation of beacon profiles (see Installation of beacons for plaster without problems), you should wait for the complete drying of the solution with which the beacons were fixed. Only then can you start plastering.
Wall surface plastering
The cement mortar for plaster must first be properly prepared. This will significantly affect the durability of the coating and its appearance.
- Quite often used cement-lime plaster mortar. It is quite qualitatively and evenly laid on the plane. In addition, this composition will serve as a heater.
- Plaster cement-lime mortar includes not only sand and cement, but also lime.
Note: The proportions of the cement mortar for plaster may be different. But there is a pattern here: the more cement there is, the faster it will solidify and be stronger.
Having completed all the preparatory work, you can proceed directly to the plaster. As soon as the lighthouses are completely frozen, they begin to prepare the cement mortar.
- The amount of sand in the solution can be determined based on the brand of cement. Four buckets of sand must be added if the grade of cement M is 400, five buckets if the grade of M is 500, etc. The amount of cement in the solution can be increased when there is no confidence in the manufacturing company.
- There are times when you have to use old cement, then you need to mix the ingredients at the rate of one to three.
- To mix the mortar, you can use a concrete mixer. But the use of a concrete mixer is justified only when plastering large areas. At home, you can use either a trough or an old bathroom.
- The finished solution in a vertical position, the trowel should slide off the tool, but at the same time hold on to it with a slide.
The process of spraying and leveling the solution
Depending on the area of plastering, the cement mixture is poured onto the surface to be treated with a trowel or bucket. The choice of the instrument is also influenced by personal preference, performing this person’s work.
So:
- Pour the mixture correctly from the bottom up. Moving your hand toward the wall, you should deploy the trowel parallel to it, and only as close as possible to the surface of the wall, you need to quickly deploy the tool 45 degrees and feed it up. This method helps the mixture not to fly apart.
- The mixture is poured onto the surface until it equals the level of the beacons. Having thrown the solution on a small surface, it is necessary to level it with the rule.
- The rule is pressed to the lighthouses and raise it from the bottom in the upward direction. At the same time, the rule should be to move from one side to the other until the cement mixture lays in an even layer.
- Then they throw another plot and also level it with the rule. So, site after site level the entire surface of the wall. In places where traces of corrosion are visible, you need to trow the cement mixture with a trowel and align it with the rule.
Grouting
You need to wait until the solution dries. This is determined by a light click on it. No dents should form on the surface. Only now can we begin trowelling.
- Using a board for grouting in a circle, they drive along the surface of the wall until it reaches the desired smoothness. If the plaster has traces of corrosion, then a cement mixture is applied to them and rubbed to a finished state. Grouting can be done the next day, for this, slightly wetting the plastered wall.
- In order to prevent cracking of the plaster layer, it must not be allowed to dry quickly. High temperatures are strictly contraindicated. The wall needs to be moistened sometimes, pouring water. With effort and patience, you can get a perfectly flat wall. But you have to carry out several stages of grouting.
Attention: Please note that all used tools must be constantly moistened to avoid cement mortar sticking to them. Leaving the tools at night without first washing them is unacceptable. These requirements apply to tanks for mixing cement mixture.
Plastering walls does not require a high level of professionalism, therefore, following the above recommendations, you can easily deal with this yourself.
