Plastering of corners, their diagnostics and methods of leveling, preparation for work and processing technologies for various types of joining walls. Plastering the corners is the stage of preparing the walls for an even state for their further design. It is quite difficult, because it involves working with surfaces located in different planes. Nevertheless, this procedure is mandatory, since curved corners can cause defects in the exterior finish and cause complications when installing furniture or equipment. Having skills in the construction business, the alignment of the corners of the walls with plaster can be done independently.
Measuring the corners of the walls and how to align them
In order to measure the deviations of the angle from the vertical and horizontal, you will need a square, a plumb line or a building level, an even piece of aluminum profile at least 2 meters long and a ruler.
To define depressions and protrusions, you need to attach a piece of profile to the corner. Then you need to install it in a vertical position, which is checked by the building level. After completing these steps, you should measure with a ruler the maximum deviation of the angular line from the vertical of the installed profile - this will be the desired skew.
The horizontal deviation of an angle from 90 degrees can be measured with a large angle. It should have long sides - almost from one wall to the other. You can make such a tool using the property of the Egyptian triangle and two long rules.
In the Egyptian triangle, the presence of a right angle is determined automatically by the aspect ratio - 3: 4: 5. Therefore, such a figure can be drawn on the floor, and then on its sides align the two rules and fasten them together in the form of a right angle. This tool can be useful for further work: on one wall, beacons under plaster are installed in the usual way, and on an adjacent plane - along a square.
The rectangular shape of the room can be checked in another way. To do this, measure the diagonals of the room. They must be the same.
If it turns out that after checking the walls have significant irregularities, forming angles that do not correspond to the norm, they can be leveled using drywall sheets that are attached to a frame that can correct any curvature, even half a meter. However, this technology will take away a certain part of the living space, to which the owners are usually very reverent.
With small flaws in the walls, the alignment of their corners is done with plaster, while the useful area of the room is preserved as much as possible. This method is more laborious and involves a rather dirty process, but it is highly reliable, creating a monolithic coating.
Preparing wall corners before plastering
In order to perform high-quality leveling plaster of corners, you should have the necessary tools, prepare the surface of the walls and know certain rules of work. Now let's talk about all this in order. The ideal material for leveling corners and walls is gypsum-based plaster. It allows you to gradually increase the thickness of the coating by applying thin layers of the mixture to the surface. Due to the rapid polymerization of the material, the plastering process is not delayed for a long time.
To work with such a mixture, you need to select the appropriate tools:
- The rule … They are served by a rigid aluminum rail 10-12 cm wide and at least one and a half meters long. It allows you to accurately assess the condition of the plaster layer: its texture, bumps and depressions.
- Poluterok … This is a wooden, steel or polyurethane board 500-700 mm long with a handle fixed perpendicularly on its non-working surface. The tool is used to apply and level plaster mortar.
- Grater … This is also a canvas equipped with a handle, its length is 20 cm. The tool is used for grinding and grouting the surface. On graters used for finishing, the working surface of the canvas is covered with felt, rubber or foam rubber.
- Corner … A device in the shape of a right triangle. It is used as a measuring tool, a template when applying plaster and broaching mortar, performing the functions of a rule. The tool size must be large enough to capture the maximum area of the corner walls.
- Trowel, spatula … This is a type of metal spatula equipped with a handle. A trowel is required for throwing gypsum plaster onto walls. This process involves the use of a triangular scapula as most comfortable. With a small amount of work, the trowel can be replaced with a spatula.
In addition to the above tools, to prepare the plaster mixture, you will need a container and an electric drill with a mixer nozzle for mixing the solution.
Before making an even corner of the wall with plaster, its surface should be cleaned of old peeling coating, paint, cladding, wallpaper and other finishes. In addition, you should pay attention to the presence of fatty, bituminous or salt stains. If they are present, they must also be removed using available means.
After that, it is necessary to measure the deviation of the angle in two planes as described above and check the surface of its adjacent walls using a rule or an even metal profile with a length of at least 2 m. The longer the length of the tool, the more accurate the measurement result. The identified bumps should be knocked down with a chisel, and large depressions should be sealed with a solution and wait until it dries completely. Then the surface of the walls adjacent to the corner must be treated with a primer to reduce its hygroscopicity and remove dust.
Basic rules for plastering wall corners
Before starting this work, you should familiarize yourself with some rules, knowledge of which will allow you to successfully complete it:
- The plaster can be applied to concrete, cement-sand, brick and gypsum wall surfaces. The adhesion of the mortar to the wooden base will not work without the use of battens made of slats or mounting mesh.
- The thickness of the plaster layer on the walls is allowed to be no more than 50 mm, for individual recesses - 70 mm.
- The mixture is prepared according to the manufacturer's instructions. It indicates the ratio of water and dry powder, which must be observed when mixing the solution. A small amount of added liquid will lead to insufficient plasticity of the mixture, make it difficult to work with it and can cause cracks on the surface of the plaster after it dries. Too much water in the solution will not allow it to gain the required strength and fill the grooves on the walls with high quality. It is not recommended to use industrial water: it should not contain foreign impurities.
- After kneading, the solution must be worked out within half an hour. Therefore, it must be cooked in small portions. You should not try to "revive" the drying mixture with water, except for the deterioration of the quality of the plaster, this will not lead to anything.
- The deviation of the angle line when plastering it should not be more than 1 mm, this will ruin the appearance of the future finish.
- The angle between adjacent walls must be straight and strictly 90 degrees. Violation of this rule will lead to problems in the laying of rotary pipe elements, docking of baseboards and installation of furniture.
After preparing the walls, you can proceed to leveling plaster of their external and internal corners.
Interior wall plastering
With significant flaws in the surfaces, plastering of the corners of the walls along the beacons is performed, and their small irregularities at the joints are corrected using a special corner profile equipped with a reinforcing mesh - a counter-shell.
Plastering the corners of the walls along the lighthouses
This method of plastering corners is used when leveling walls around the entire perimeter of the room. For work, you will need a large square, the manufacture of which was mentioned above.
First of all, you need to choose a support wall, mark the location of the beacons on it and fix the screws according to it. By placing their caps on the same level, the base plane is formed. This procedure is performed using a plumb line.
The next step is to set the bottom and top screws away from the support wall. In fact, to obtain a right angle, it is enough to correctly install the lower nearest screw. Previously, it should be screwed into the dowel as much as possible, taking into account the gap for the beacon of at least 6 mm.
After that, you need to attach the square to the pair of lower screws of the retaining wall and the far screw on the adjacent plane. Determine what to do with the screw closest to the corner. If the rule of the square does not touch its head, the screw must be unscrewed until it touches. If the rule rests against the near screw, but does not touch the distant beacon, you should unscrew the far screw. As a result of the work, the heads of the four lower screws located on different walls should create a right angle.
The upper screws are set already in level, focusing on the height of the lower screws unscrewing from the wall. After installing the lower and upper screws on both walls, you need to check the thickness of the plaster layer under the beacons. After the lighthouses have solidified, their location can be checked again with a square. The step between the beacons should not be less than the length of the rule.
The mortar is applied first from one side of the corner. The cavity between the beacons is filled with a mixture and then distributed by the rule. After one wall of the corner has dried, you can go to the adjacent wall.
For smoothing the joint of the walls, a special corner spatula is used, which greatly facilitates the work. Hand movements should be directed from the corner. In the process, the tool must be periodically moistened in water.
Plastering the corners of the walls with the use of countersunk
This method is good if the walls are already aligned, and you only need to arrange the corners. To perform this work, you need to cut off a piece of a corner with a reinforced mesh with metal scissors. Its length should be equal to the height of the corner. Aluminum contrashultz is rather soft, for this reason, you should not apply special efforts to it, so as not to disturb its shape.
Then, a little gypsum mixture should be applied to the joint of the walls with a spatula and distributed along the height of the corner. A piece of counter-crust should be attached to the corner and, using a long rule, press it down slightly. The work should be done carefully, since the metal of the corner is rather thin and easily deformed.
Excess plaster mix will be squeezed out through the profile perforation. This solution must be transferred with a spatula to the counter-grinder mesh, smoothing it.
When the mixture is dry, the surface of the corner should be sanded with a fine-mesh abrasive mesh. If the surface is being prepared for painting, it is necessary to apply a thin layer of fine-grained gypsum plaster on it, level it and wipe it after drying.
Wall corners plaster with reinforcing tape
With the help of plaster, an even corner of the walls can be obtained using a wide reinforcing tape-serpyanka. This method is used only for the formation of a joint of surfaces at an angle of 90 degrees and does not provide for their complete alignment.
For work, you will need gypsum plaster, a wooden block of strictly rectangular section and 40-60 cm long, as well as a reinforcing tape.
A small amount of plaster should be applied to the junction line of the walls, taking 10 cm from each adjacent surface. Then the edge of the serpyanka must be attached to the top of the corner and, holding it at this point, unwind the roll to the bottom, as far as the width of the arms coverage allows. When performing this procedure, it is important that the serpyanka does not deviate from the given direction and evenly overlaps the joint.
After gluing the tape with plaster, you should take a block, and then with pressing movements along the joint line and its planes, give the corner a straight shape. The crumpled tape on the walls can be leveled with a spatula, and the excess mortar can be transferred to the rest, distributing it from the corner line. It is necessary to work with a spatula carefully so as not to disturb the position of the tape at the joint. After the mixture dries, the reinforced corner coating should be sanded with an abrasive mesh or sandpaper.
Plastering the outer corners of the walls
Beautiful and perfectly shaped outer corners can be achieved with or without a perforated metal profile. In the first case, the strength of the corner will be higher.
Plastering the outer corner of the wall without reinforcement
Before starting work with this method, all protrusions should be knocked down with a chisel from the walls adjacent to the corner with a chisel and large slots should be sealed with a solution. The process begins with the installation on the side of the corner of a flat board or wide strip, which will serve as a kind of formwork. Fastening is made to the floor and ceiling, but if you choose the optimal length of the board, you can set it up. The board should be wrapped with tape and protrude from the outside of the corner at a distance equal to the thickness of the plaster layer. The tape is designed to prevent the mortar from sticking to the surface of the "formwork".
Then, plaster is applied to the surface adjacent to the corner and distributed over the entire height of the joint using a rule. Movements are made towards the corner with a slight downward inclination.
After at least two days, you need to carefully dismantle the board and attach it in the same way to the already plastered side of the corner. Then repeat the above procedure with the other wall.
The finished corner is sanded with emery paper or a float equipped with an abrasive fine mesh.
Plastering the outer corner of the wall with a profile
The metal profile forms an even line of the corner and protects it from accidental mechanical damage. It is not difficult to calculate the number of aluminum corners: you need to measure and sum up the lengths of all external wall joints and add 10% to the resulting figure, taking into account the waste of material during installation. The standard length of the corner is 3 m, and the height of the premises is from 2, 5 to 2, 8 m. Thus, 20-50 cm of the profile will be wasted in the form of scraps for each corner. They can be useful for forming short corners on ledges in walls or ceilings.
To form a right angle when plastering walls on its adjacent surfaces, you first need to apply the prepared gypsum mixture.
The corner of the required length is attached with pressing movements to the area processed along the entire height of the joint. It is advisable to perform this work with a rule that will prevent the deformation of the corner from careless pressing with your hand.
Excess mixture, squeezed out through the perforation of the profile, is transferred with a spatula from its metal part to the mesh. Immediately after mounting the corner, its position on the wall should be checked with a building level. As long as the mixture is not frozen, any adjustment is possible.
After the plaster has dried, the corner of the wall should be sanded with an abrasive material. Finishing of the corner is carried out in conjunction with the walls.
Plastering rounded corners of walls
The rounded corners of the walls are not difficult to plaster. First, the adjacent surfaces of the junction of the enclosing structures should be leveled with a gypsum mixture according to standard technology. When creating rounds, the planes of adjacent walls act as beacons, and the rules are a special template.
It can be made like this: a strong plastic wire must be pressed into a rounded corner, the shape it acquired will give the outline of the future template. Then the sample must be attached to thick plywood and trace around it with a pencil. Along the resulting line, you need to cut off excess material. The template is ready.
Then, at an angle along its entire height, plaster mortar should be thrown and its excess should be removed with a template. Small ellipses do not require reinforcement. But when making rounds with a diameter of more than 100 mm, they must be strengthened with a wire or reinforcing mesh. You can get by with the use of screws. They are screwed into the rounding in increments of at least 200 mm.
After the plaster of the corners has dried, you need to apply the last finishing layer with the addition of fine sand to the solution. This coating is rubbed with felt to create the smoothest possible rounded corner surface. Grout should be done only with horizontal movements.
How to plaster the corner of a wall - watch the video:
Plastering and leveling corners is considered the most difficult task, especially for beginners. It requires a fairly high level of professionalism. However, with a conscientious and unhurried approach to this matter, you can create even corners in the room on your own. The difference when the work is done by professionals is in this case only in the time that will be spent on it.
