Materials for the preparation of dissimilar surfaces for plastering. Plastering the facade - preparation of the base

When viewed without magnification, the surface must be free from visible oil, grease, and dirt, as well as weakly adhering scale, rust, paint, and foreign particles (mill scale, rust, or paint coating are considered to be poorly adhering if they can be removed by lifting with a blunt trowel ).

Sa 2 - Thorough blast cleaning

When viewed without magnification, the surface shall be free from visible oil, grease and dirt, as well as most of the mill scale, rust, paint and foreign particles. Any remaining contaminants must adhere firmly.

Sa 2 1/2 - Very thorough blasting

When viewed without magnification, the surface shall be free from visible oil, grease and dirt, as well as from mill scale, rust, paint and foreign matter. Any remaining traces of contamination should only appear as light staining in the form of spots or streaks.

Sa 3 - Blasting to visibly clean steel

When viewed without magnification, the surface shall be free from visible oil, grease and dirt, as well as from mill scale, rust, paint and foreign matter. It should have a uniform metallic color.

In other words:

• degree of purification Sa 2 - 76% clean surface;
• degree of cleaning Sa 2 ½ - 96% clean surface;
• degree of cleaning Sa 3 - 99% clean surface.

Removal of dust, abrasive residues, etc.

Although paint adheres well to dust, dust does not adhere to steel surfaces.

This leads to poor adhesion of the coating and thus to its sensitivity to mechanical stress and peeling, and hence to early corrosion.

Therefore, insufficiently cleaned areas should be cleaned again with a clean compressed air.

Removal of water-soluble salts

In order to steel sheets there was no salt, it is necessary to store them under a canopy or arrange a fresh water cleaning procedure before the material is taken into production.

If salts are found on the surface, they must be removed with water. Jet wash recommended fresh water from a high-pressure hose or water from a hose while using stiff brushes.

For excessive pitting, hosing down should be done during or after cleaning the corrosion pits. Wet or dry sandblasting followed by high pressure hosing and dry cleaning again is recommended.

Water-soluble anti-spatter agents must be removed with water. Other types must be removed by solvent cleaning.

Roughness value

Three factors are important for an abrasive-cleaned profile: height, shape, density.
When the profile exceeds the allowable level, then the peaks appear above the surface of the coating, leading to its destruction.
Too low height, round shape and low density prevent proper adhesion of the applied coating. The result will be poor adhesion, which will cause hypersensitivity to mechanical impact on the coating and its destruction to steel, which will lead to early corrosion.
Too high a profile can cause the tops of the profile to show through the coating, resulting in early pitting.
The profile cannot be too sharp or too tight.
How to fix?
Surface areas showing too low height, rounded profile or too low density, must be refinished using a coarse abrasive.

Final quality control of surface preparation should be carried out immediately before plastering or painting.
Generally, most paint schemes require the following levels of metal surface condition to be achieved.

Metal surface preparation

In most cases, when preparing the surface of non-ferrous metals and aluminum alloys, GOST 9.402 is followed. When painting fresh galvanized steel with an intact zinc coating, degreasing is generally sufficient. More time-consuming surface preparation of old galvanized steel, where in addition white coating on the old zinc coating and rust from carbon steel formed in places of damage zinc coating should be removed with mechanical tools.

Preparation of brick surfaces and concrete

The surface should not have protruding reinforcement, shells, sags, chipped ribs. Embedded products must be rigidly fixed in concrete; aprons of embedded products are installed flush with the surface to be protected. The places where the floor adjoins columns, foundations for equipment, walls, and other vertical elements must be monolithic. Supports of metal structures are concreted.

Concrete and brick surfaces that have previously been exposed to acidic aggressive environments should be pre-washed with clean water, neutralized with an alkaline solution or a 4-5% soda ash solution, washed again and dried.

Before applying most coatings, and especially epoxy resins, the surface must be thoroughly dry; humidity of concrete surfaces in the surface layer of 20 mm should not exceed 4%. As a rule, this occurs after it has been kept at 20°C for 28-30 days after pouring concrete.

Preparation of the concrete surface before painting with any paintwork materials must be thoroughly cleaned of mastics for formwork, loose layers of screed, efflorescence and cement "milk" and other contaminants, degreased, puttyed if necessary, cleaned and thoroughly dedusted. In critical cases, it is useful to carry out water jet and hydroabrasive cleaning of concrete, followed by surface drying. Before painting brickwork brick sandblasting required old paint and pollution.

The presence of oil, grease, mastic and other contaminants can be determined as follows: draw lines with chalk through the suspected stain of contamination, pressing the chalk with average strength. If the line in some place has a lower intensity than in neighboring areas (before and after the alleged spot), then this means that this area needs to be degreased.

K category: Plaster work

Preparation of surfaces for plastering

Preparation for plastering stone, brick and concrete surfaces. The strength and durability of the plaster largely depend on the cleanliness and roughness of the bases, which ensure good adhesion of the plaster mortar to the surface to be finished. Insufficiently clean and rough bases are prepared in various ways.

Dirt from the surface is scraped off with a steel brush or spatula.

Stone, brick and concrete surfaces:
- for cleaning from soot, they are washed with a 3% solution of hydrochloric acid, followed by washing with clean water;
- stains of non-drying oils are coated with greasy clay with a layer 0.5-1 cm thick. After complete drying, the clay is removed and the surface is washed with clean water;
- salt efflorescence is removed with a steel brush, after which the surface is washed with a 0.5% hydrochloric acid solution, and then with clean water.

To remove the old color and roughen stone and concrete surfaces, as well as previously plastered or brick surfaces laid without waste, they are cut manually with a double-sided pointed hammer or an IP4112 pneumatic chipping hammer. At the same time, the number of notches per 1 m2 of the surface should not be less than 300.

The same tools cut down the influx of mortar on brick or masonry and concrete.

To roughen concrete surfaces, they are sometimes treated with a 15% hydrochloric acid solution, followed by rinsing with clean water.

With large volumes of work, roughening surfaces made of old brick, smooth concrete and painted with water-based paint compositions is achieved by sandblasting.

Tools and machines for preparing stone, brick and concrete surfaces for plastering are shown in Figure 65.

The preparation of stone, brick and concrete surfaces is carried out by a link of two plasterers. When processing surfaces in rooms up to 3 m high, inventory tables are used with or without flip-over boards, and towers are used for rooms with a height of more than 3 m.

When working with a mechanized tool, workers must ensure that the tips (scarpels, trojans, bush hammers) are well fixed in the tool body, the compressed air hoses have reliable butt joints and are firmly attached to the hammer and compressor nozzles. It is allowed to work in tightly buttoned overalls, gloves and goggles.

When working with hydrochloric acid solutions, workers should be provided with on-duty protective equipment for the duration of work: acid-resistant suits, rubber aprons, gloves and half boots, as well as goggles.

An exercise. Determine how many notches need to be made on the side planes of the brick when laying it with a poke or spoon, if at least 300 notches per 1 m2 must be applied to give the surface sufficient roughness.

Rice. 1. Tools and machines for preparing surfaces for plastering: a - double-sided hammer with double sharpening; b - bush hammer; c - plaster hammer; g - plaster knife; d - nippers (nippers); e - compressor unit; g - trojans; h - scarpel.

Reinforcement of plaster and arrangement of bases reinforced with mesh. For the reinforcement of plaster and the installation of mesh reinforced bases, woven wire mesh 1 m wide with square cells measuring 10X10 mm is used. Wire diameter 0.7-3 mm. The mesh is tied to the frame with a copper-plated or galvanized knitting soft wire with a diameter of 0.8 mm. The panels are overlapped in length and width with an overlap of 50 mm and firmly fastened together with knitting wire. The mesh is cut into panels of the required length and width with manual scissors for cutting metal.

Rice. 66. Wire weaving mesh on nails: a - single; b- double.

Furrows with hidden pipelines in masonry are tightened with a mesh, tying it to metal staples made of steel with a diameter of 6-8 mm, hammered into the seams of the masonry 20-30 cm across the furrow, or fixing the mesh with nails 80-100 mm long, hammered into the seams of the brickwork through 20-30 cm on both sides of the furrow.

Before laying in place, metal beams, including girders and stringers, are wrapped with mesh with binding over the mesh with knitting wire in a spiral with a step of not more than 15 cm. In the absence of a mesh, beams and stringers are tied with a knitting wire in a spiral with a step of not more than 5 cm.

To form a gap between the shelf of the beam to be plastered and the mesh, 2-3 steel bars with a diameter of 6-8 mm are welded or tied to the shelf.

Door and window slopes, as well as individual places with a notch thickness of more than 20 mm, before plastering, they are reinforced with a mesh with its fastening with nails or moldings gypsum mortar. In the absence of a mesh, weaving is made from wire with a diameter of 0.8-1 mm along incompletely hammered nails 80-100 mm long.

The joints of wooden structures with stone, brick, concrete and gypsum concrete are reinforced with mesh strips 15-20 cm wide, fixed to wood, brickwork seams and gypsum concrete after 15-20 cm with nails, and to stone and concrete - by freezing with a solution.

Rice. 2. Reinforcement of plaster at the junction of wood and brick.

Reinforced mesh bases for plaster are made when making lightweight structures of partitions, suspended ceilings, decorative columns, pilasters, corbels and cornices, made for architectural reasons and in order to save materials, as well as, if necessary, isolate the plaster from damp walls, basement walls, etc. When making lightweight partitions, the mesh is nailed with wire staples or nails every 15 cm to wooden bars thickness and width of 25-50 mm, reinforced in advance in 30-40 cm. Mesh bases for hanging ceilings in wooden buildings are also made.

Rice. 3. Reinforced mesh structures: a - a partition with a mesh along wooden bars (1 - vertical bar, 2 - horizontal bar, 3 - mesh); b - suspended ceiling with mesh fastening to rods (1 - hooks, 2 - rods, 3 - mesh); in - columns and columns with fastening of the grid to the frame (U - vertical rods, 2 - grid).

on brick and concrete walls and ceilings, the mesh is tied to steel rods with a diameter of 6-8 mm, welded to pre-installed pins, hooks, pendants made of round or strip steel. The rods are welded to form a cell of 40X40 cm. To ensure a plaster layer of the minimum allowable thickness on the walls and ceilings (at least 20 mm with a high-quality finish), the rods are installed on pre-made wooden or mortar beacons in 0.8-1 m.

On pillars, columns and pilasters, the mesh is tied to a frame formed from vertical metal rods fixed to wooden planks or circles (with round columns) with nails or to steel horizontal belts with a diameter of 6-8 mm by welding. The metal frame should form cells measuring 40X40 cm.

The metal mesh is tied to metal frames at each intersection of the rods with a knitting wire, using wire cutters when tightening the knots. the best way fastening the mesh to the frame should be considered as tying it with a spiral seam, using for this the ends of the wire up to 2 m long, with which the mesh is sewn to the frame rods.

The first layer of plaster over the grid is applied from a thick cement mortar (consistency 3-4 cm according to a standard cone) by coating with reinforcement of the solution with wool or chopped organic fiber.

In the case when it is supposed to be plastered over the grid with a lime-gypsum mortar, the grid is preliminarily painted oil paint, bituminous varnish or make a coating of the grid cement mortar, and subsequent plastering - lime-gypsum.

To ensure a strong adhesion of the solution to the surface to be plastered, it must be well prepared by creating additional artificial roughness on it, as well as clean the surface from dust and various contaminants. Even a small amount of dust and contamination of the surface greatly reduces the adhesive strength of the solution with it.

Plastering has to be done on stone, brick, concrete, slag concrete, gypsum, wood, straw, reed and other surfaces.

Before proceeding with the preparation of surfaces, it is necessary to inspect them, check the strength of fastening and the accuracy of execution.

So, for example, the permissible deviations of the surface of the corners of the masonry from the vertical on one floor of a concrete wall with a height of 3.2 to 4 m can be no more than 20 mm; for brick walls - no more than 10 mm, and for the entire height of the building for walls made of rubble concrete or brick - no more than 30 mm.

If the surfaces are intended for plastering, then irregularities on the vertical surfaces of the masonry are allowed for walls made of rubble concrete 15 mm, and brick - 10 mm. Deviation of masonry rows from the horizontal per 10 m of wall length is allowed up to 20 mm. For concrete and reinforced concrete surfaces, deviations from the horizontal are allowed by 1 m to 5 mm, and for the entire plane no more than 10 mm.

For wooden walls frame buildings deviations in all directions of no more than 10 mm are allowed, and for panel boards - 5 mm. For plank partitions and walls, deviations of 1 m in height are not more than 3 mm, and in length not more than 10 mm.

Before surface preparation begins, various grooves, channels and niches must be punched. Places of installation of heating devices and pipelines with their open wiring must be plastered. When there is hidden electrical wiring, channels or grooves must be punched and tubes of appropriate materials laid in them. Window and door frames must be properly installed and securely fastened.

It is best to entrust all work on surface preparation to auxiliary workers, highlighting for their guidance and assistance necessary assistance qualified plasterer. Work must be carried out strictly according to specifications, which determines the quality of surface preparation.

After preparing the surfaces of the ceilings, the installed scaffolds are not removed, the ceilings are plastered from them.

Scaffolding and floors must be well swept so that the mortar falling during plastering does not mix with debris, and the mortar collected from the floor can be used without sieving.

The base for plaster must adhere firmly to the plaster mortar. Surfaces intended for oshtu; curing, incised, cleaned, moistened with water, if necessary, cut off the influxes on the surface, choose the seams. In all cases, contaminants are removed from the surfaces, especially May, tar.

Rubble stone walls are prepared as follows; Masonry seams, if they are flush filled with mortar, are chosen to a depth of at least 15 mm, and the surfaces are cleaned with steel brushes. When laying, it is better not to fill the seams to this depth, insert pieces of wire into them at intervals of 10-15 cm or wooden corks and hammer nails into them. A wire plexus is made along the wire and nails, on which the plaster cast is well held. New brick walls, folded empty, are swept with a broom or broom. If the joints are filled with mortar, they are selected to a depth of at least 15 mm.

Old brick walls are prepared in the following sequence: seams are selected, the surface is cleaned with steel brushes or sandblasting, or notched. Slag concrete surfaces, new and old, are also notched. For better adhesion to the plaster layer, holes are drilled in the cinder-concrete surface, plugs are installed in them, and a wire plexus is arranged along the nails driven into the plugs.

When preparing surfaces, they are cleaned with steel brushes, as well as trowels, on which brushes are attached instead of a trowel disc. Surfaces are incised manually with an ax, bush hammer, cog, chisel, applying strokes on the surface - strips or pits with a depth of 3 to 5 mm. Bucharda has 16-26 pyramidal teeth on the ends or cutting in the form of straight blades. The chisel has a smooth long blade. Gear, trojanka, scarpel, tongue and groove - varieties of chisels with teeth on the blade. Tongue - a round rod, the end of which is processed into four faces, like a nail. It is convenient for them to choose seams or chip off pieces of hardened mortar when processing plaster.

When preparing surfaces, safety regulations must be observed. All tools must be firmly attached

on durable, burr-free handles. Work should be carried out in gloves and goggles. The power tool must be checked for conductance.

Cornices, corbels, columns, pilasters are often framed with a mesh, and then plastered with any solutions for different textures, but without processing the applied plaster percussion instruments. Set it up like this. First of all, a supporting frame is placed, a distribution frame is welded to it or tied with wire, along which the mesh is stretched, often attaching it. It is necessary to stretch the mesh as tight as possible, since a loosely stretched mesh vibrates, and the solution applied to it will fall off. Before plastering with lime-gypsum mortars, the mesh is painted over with oil paints or cement milk. This protects it from rust and destruction.

To create roughness, shingles are stuffed onto wooden surfaces (Fig. 5.1). So that the surfaces do not warp, the boards are split and wedges are driven into the splits. To reduce sound and heat conduction wooden surfaces before stuffing the wounds, they are covered with matting, felt. Before stuffing, the shredding is sorted into pro-style (at least 3 mm thick), narrow and outgoing, more even and thicker (not more than 5 mm thick); blade width from 15 to 20 mm; wider shreds warp.

Rice. 5.1. Wrapping and tools used:
a - plaster knife; b - plaster hammer; in - the location of the potato pancakes; g - stuffing of wounds; 1, 2 - nails

First of all, a prostrate shred is lightly nailed to the surface. Having stuffed it with a whole row along the length of the wall, they begin to stuff the output shred. Both shreds are nailed at an angle of 45 ° to the floor so that cells are formed. A distance of 45 mm is left between the pancakes of the prostyle and the output row, thereby forming cells or cells 45 x 45 mm in the light. The output shingle is nailed with plaster nails through two prostrate pannels into the third. In the course of work, the nails slightly driven into the prostile shred are taken out and used. Dranitsy join the ends, and do not impose one on the other. The ends of the fray must be nailed. Stuffing piece shredding is a labor-intensive operation. It is better to use shingle boards, which are assembled and fastened with nails on a workbench for laying shreds.

Sometimes, instead of shredding, a mesh is stuffed, the cells of which should not be larger than 40 x 40 mm. The mesh is fixed with nails every 10 cm, bending them. The joints of dissimilar surfaces are tightened with a metal mesh so that cracks do not appear on the plaster. Cracks form because on dissimilar surfaces plaster mortar dries up in different dates. To avoid this, the joints are tightened with a mesh with 10 x 10 mm cells, cut into strips 10 cm wide and nailed along the edges after 10 cm. If there is no mesh, wire weaving can be used. To do this, nails are hammered through 40-50 mm and they are braided with wire. Metal beams between iron concrete slabs, are also tightened with a grid. To do this, reinforcement is welded to the beams in the form of a large mesh or in the form of individual rods for attaching mesh strips to them. The edges of the mesh should overlap the seams between the slabs and the beam by at least 5 cm. The mesh should be cut and stretched with gloves on.

In order for the plaster to be strictly vertical and horizontal, the surfaces are hung and leveled according to marks and beacons before plastering (Fig. 5.2, 5.3). Beacons are made of gypsum or the same mortar used for plastering, or wooden or inventory metal beacons are used. For hanging surfaces, a plumb line, a level with a rule, a water level are used. It is most convenient to hang the walls with a plumb line.

The hanging procedure is as follows (see Fig. 5.2). In the corner of the wall at a distance of 300-400 mm from the ceiling, a nail is driven in to the thickness of the plaster. A plumb line is lowered from the head of this nail to the floor and nail 2 is driven in below so that its head almost touches the cord. On walls above 3 m, an intermediate nail 3 is driven in. The opposite corner of the wall is also hung, driving in nails 4, 5 and 6.

Rice. 5.2. Hanging the walls with a plumb line:
a - plumb; b - hanging scheme; 1-12 - nails; 13 - stamps; 14 - rule; 15 - lighthouse

After that, the cord is pulled over the heads of nails 1 and 3, then 2 and 4. If the surface of the wall is even, then the hammered nails are left in it. If the cord touches the surface, it is cut down in this place. When this is not possible, then in one row the nails are pulled out to such an extent that plaster is obtained in a convex place. desired thickness. Then the cord is pulled over the heads of nails 1 and 4, 3 and 5, 2 and 6, driving intermediate nails 7, 8, 9, 10, 11 and 12 along the tensioned cords, along which beacons will be arranged. The distance between the beacons can be from 1 to 3 m.

Having hung all the walls, they proceed to the device of stamps and lighthouses. Gypsum dough or mortar is smeared on each driven nail, its front side is leveled at the level of the nail head and cut off from the sides. Stamps are made in order to establish a rule on them, which is fixed with plaster, nails or clamps. Under the rule, gypsum or mortar is applied. After the gypsum or mortar has set, the rule is removed by striking it with a hammer. A strip of mortar, called a beacon, remains on the wall. There are defects on it, they are corrected and rubbed with a half-cloth. To hang the rule with a level, nails are driven into the ceiling in rows to the thickness of the plaster. Then they take any nail for the main one, attach one end of the rule to it, and the other end to one of the hammered nails. When pulling out or driving in a nail, the rule is set exactly according to the level. Thus, from each precisely installed nail, further installation of hammered nails is carried out, on which stamps and beacons are then smeared.

Rice. 5.3. Hanging the ceiling with a water level:
a - level detail; b - hanging; 1 - rubber tube;
2 - glass tube with divisions; 3 - nail
On fig. 5.3 shows hanging the ceiling with a water level. If the water is on the same scale at both ends of the level, then the surface of the ceiling is horizontal.

One of the most important factors determining the quality of plaster is its strong adhesion to the surface on which it is applied. If the adhesion is not strong enough, the plaster peels off the surface, and then disappears. For a strong adhesion of the solution to the surface, it must be properly prepared, i.e., roughened it, cleaned of dust and other contaminants.
Are exposed to plastering various surfaces: stone, brick, concrete, cinder-concrete, wooden, straw, reed, adobe, etc.; they all require different training.
The complexity of surface preparation depends solely on its type, i.e., on the degree of hardness. Gypsum, cinder-concrete, brick surfaces are the easiest to process, concrete surfaces are very difficult to process.
Before preparing the surfaces, it is necessary to check the verticality and horizontality of the structures, as well as the strength of their installation.
If during the verification process even small deviations of surfaces from the requirements of SNiP (Part III, Section B, Chapter 13 of the Building Codes and Rules) are revealed, they should be eliminated, since deviations of walls and partitions from the vertical, and ceilings from the horizontal, require the application of thickened mortar marks ( with improved and high-quality plaster), and this leads to an overrun of material, a decrease in labor productivity and an increase in the cost of work.
Permissible deviations of masonry angles from the vertical on one floor of a concrete wall with a height of 3.2 to 4 m must be no more than 20 mm, for brick walls no more than 10 mm, and for the entire height of the building for walls made of rubble concrete or brick, do not exceed 30 mm.
Irregularities on vertical surfaces of brickwork intended for plastering are allowed: for walls made of rubble concrete no more than 15 mm, and from brick up to 10 mm. Deviation of masonry rows from the horizontal by 10 m wall length allowed up to 20 mm. For concrete and reinforced concrete surfaces, deviations from the horizontal are allowed by 1 m lengths up to 5 mm, and on the entire plane no more than 10 mm.
For wooden walls of frame buildings, deviations in all directions are allowed no more than 10 mm, and for panel boards 5 mm. For plank partitions and walls, deviations of 1 m height no more than 3 mm, d length not more than 10 mm.
Prior to the preparation of surfaces for plastering, door and window frames should be installed, and large through holes between the boxes and walls should be bricked. Under all kinds of devices, the necessary fasteners must be supplied - hooks, bolts.
After preparing the horizontal surfaces (ceilings), all scaffolds installed for this are left, as they will be required for plastering. Having prepared the surfaces, the decks on the scaffolds and the floors below them are swept so that the fallen mortar is not contaminated during the plastering process and can be used again without sieving.
Preparation of stone-like surfaces. New walls, built of rubble stone, are prepared as follows. Masonry joints, if they are flush-filled with mortar, are selected to a depth of at least 15 mm and the surfaces are well cleaned with steel brushes.
In order not to waste time sampling the mortar from the joints during masonry, it is recommended to arrange joints with a depth of 10-15 mm. Even better in masonry joints after 100 - 150 mm insert pieces of wire, with the help of which wire weaving is easily made to hold the stucco plaque.
It is also possible to insert wooden checkers (corks) with a thickness of 15 mm, length 100-150 mm. Before execution plastering works nails are driven into these checkers to the desired depth, along which wire weaving is performed. Instead of wire, you can attach a mesh.
New brick walls, folded into a wasteland and having sufficient roughness, it is recommended to clean with a metal brush and water with water before plastering. If the seams of the brickwork are filled with mortar to the full depth, then they are selected to a depth of at least 10 mm. New and old cinder concrete surfaces require especially careful preparation, because plaster does not adhere very well to them. For strong adhesion of the plaster layer with the indicated surfaces, when forming cinder-concrete stones or stuffing walls with cinder-concrete, it is recommended to lightly fasten reinforcing wire or wicker rods with a diameter of 6-8 on both sides of the formwork mm, placing them vertically or horizontally at a distance of 50 mm from each other. Instead of reinforcing wire or willow bars, thin rubber tubes or a rubber cord with a diameter of up to 10 mm which is easy to take out.
After two or three days, when cinder concrete is released from the formwork, the attached reinforcing wire, wicker rods, rubber tubes or cord are removed and grooves remain on the surface, into which, during plastering, a solution enters, which firmly sets with the plaster.
Cinder-concrete walls unprepared in the above way must be carefully cleaned with a steel brush and notched before plastering. The best results can be achieved if holes are drilled along the notched and cleaned surfaces - nests up to 20 mm, diameter 10 - 12 mm. Nests should be placed at a distance of 50 - 70 mm from each other in checkerboard pattern. The mortar is firmly held in these holes, and the plaster adheres well to the surface.
New partitions made of gypsum or gypsum concrete slabs must be cleaned with steel brushes. This will ensure a strong adhesion of the applied solution. Partitions made of such slabs, which have stood for more than a year, are recommended to be cut, treated with steel brushes, then thoroughly cleaned of dust and weakly adhering pieces of gypsum and rinsed with water.
Oils, paints, resins and other similar materials should be completely removed from the surface, since even with small residues of these materials, hard-to-remove, and sometimes even completely unremovable stains appear on the plaster.
Tools and methods of work. Surface preparation with a small amount of work is carried out with hand tools.
Clean surfaces with wire brushes. The stronger and thicker the wire, the harder the brush. The brush not only cleans the surface, but also scratches it.
The brush is taken with one or two hands, pressed against the surface and moved in different directions. This removes a thin layer of material and dirt from the surface.
Surfaces are cut with an ax, bush hammer, cog, chisel.
When notched with an ax, flat strokes-strips 10-15 long remain on the surface. mm, depth 3-5 mm.
Bush hammer (Fig. 12, a) is a small sledgehammer, on the ends of which 16 - 36 teeth of a pyramidal shape are notched, or there is a cut in the form of straight lines. Bush hammer is taken with two hands and its end, which has teeth or cuts, is struck. From the cloves there are pits, from cutting - strokes.
The chisel (Fig. 12, b) is less productive, so it is advisable to use it for sampling joints in masonry. The chisel is directed along the length of the seam at an angle of 30-45° to the surface.

The gear (Fig. 12, c) is a chisel with several teeth on the blade. During operation, it is held with the left hand at an angle of 30 - 45 ° to the surface, and with the right hand, armed with a hammer of mass 1 kg, strike. Lighter hammers are inefficient.
When working with a gear and a chisel, gloves and goggles should be worn.
For the treatment of concrete surfaces, various electrified tools and mechanisms are used. Jackhammers are used for notching and sampling seams. Lightweight jackhammers are either electric or pneumatic. The most widely used electric jackhammers (Fig. 13).

To increase productivity, a bush hammer or a gear is inserted into the electric jackhammer instead of a chisel.
Various pneumatic and electric tools also used to clean surfaces from bumps, sags, protrusions. Surfaces can be cleaned electric brush with a flexible shaft or low-speed electric drill. To do this, put on a disk with steel brushes. successfully doing this job and trowel, to which a steel brush is attached instead of a grater.
Most efficient surface cleaning sandblasting machine(Fig. 14), which works as follows. Dry sifted sand of medium size (1-3 mm) fall asleep in the cylinder of the apparatus 2 through the hopper 1 . Wet sand cannot be used for sandblasting, as plugs are formed that clog the hoses or nozzle 4 which causes the machine to stop.

Under the strong pressure of compressed air, sand from the conical part of the cylinder 3 comes in the tube 4 , and from there into a rubber hose, at the end of which there is a mouthpiece-nozzle with two tubes. A hose for sand supply is connected to one of the tubes, a hose for supplying compressed air from the compressor is connected to the other.
A jet of compressed air picks up the sand and forcefully throws it out of the nozzle to the surface. A jet of sand, directed at an angle to the surface, hits it with force and cleans off dust, dirt, paint, resin and at the same time roughens it.
During work, the sandblaster must wear a cloth cover with a respirator and goggles on his head.
Preparation of soil-block and earth-beaten surfaces. Ground-block and earth-beaten surfaces are scratched with a metal rake before plastering. The furrows formed in this case must be at least 5 mm. Furrows are recommended to be placed at an angle of 45 ° to the horizontal surface. Hardened surfaces are pre-moistened with water from an airbrush or with ordinary brushes, and a slightly softened wetted surface layer is scratched.
A wire braid holds the applied plaster more firmly. To do this, nails are driven into the surface, along which wire weaving is performed. However, this increases the cost of the work.
For more reliable adhesion of the plaster to the surface, the latter is moistened with water, scratched well, and then a layer of clay mortar is applied with a thickness of about 20 mm. As soon as the mortar sets slightly, holes are made in it with a diameter of 20 mm throughout the depth of the applied solution. Holes should be no more than 50 mm one from the other.
To make holes, a device in the form of a rake is used, the teeth of which have a diameter of 20 mm and located at a distance of 50 mm from each other. The device is attached to the surface at the desired angle and struck with a hammer.
After the surface treated in this way dries, a lime or lime-clay solution of a creamy consistency is applied to it with a thickness of 2-3 mm, which is called a splash. Then it is plastered.
It is considered more expedient to make holes in the earth-beaten walls themselves 2-3 days after the filling or laying of the walls.
Preparation of wood and other nailed surfaces. wooden walls can be made of logs, slabs, boards of various thicknesses or slats. Boards wider than 10 cm should be pricked, wedges should be hammered into the pricked places so that gaps 5-12 wide are formed mm. better boards pierce more often - this will prevent warping of the boards when wet wood dries; from warping or swelling of the boards, the plaster breaks - cracks.
To obtain rough surfaces, shreds are stuffed on them. To reduce thermal conductivity and sound conductivity wooden partitions, walls and ceilings, insulating materials such as matting, burlap, felt are often hung on them before stuffing. With these materials, the applied mortar adheres well, and the boards get wet less and do not warp, which largely preserves the plaster from cracking. To protect the felt from destruction, it is antiseptic - impregnated with a 3% solution of sodium fluoride and then dried.
The prepared insulating material is applied to the wall so that one end touches the floor, and nailed at the bottom with several nails. Then the material is straightened and the top is pulled so that there are no wrinkles, and along the edge it is also nailed with several nails. When hanging thin materials (matting, burlap), their edges are superimposed one on top of the other; when hanging thick ones, such as felt, the edges are not superimposed on each other, but laid back to back and nailed.
Nails are recommended to be driven in only half of their length, and the remaining half to be bent, then the insulating materials will be firmly held on the surface.
Lightly felted, which tears easily, must first be rolled onto a round wooden rod or metal pipe. As the felt roll is nailed, it is rolled out from the bottom up. In this case, the roll is pressed to the surface and make sure that the felt does not break. It is more convenient to work together: one worker rolls and stretches the material, and the other nails it.
Upholstering surfaces for plastering with soft felt is allowed only if the felt is additionally covered with glassine. If this is not done, then the roughness formed by the shreds will be covered with felt and will not provide a strong adhesion of the plaster solution to the shreds. After laying the heat-insulating layer, piece, shield shingle or reed braids are stuffed onto the surface.
Piece shaving is recommended for small amounts of work, since this operation is laborious.
Plasterboard is made from wood conifers. Depending on the method of manufacture, the shred is plucked and sawn.
Plucked shred can be ordinary, selected and veneer-new. Width of ordinary flaying 12-30 mm, thickness 2-5 mm, the width of selected shreds 15-25 mm, thickness 3-4 mm, veneer width 14-30 mm, thickness 2-5 mm.
Sawn shavings are made from wood waste. Such shredding is worse than plucked, because its annual layers have been sawn. Blade width 25-40 mm, thickness 5-7 mm.
Length of all types of flaying 1000-2500 mm. The shingle should be multi-layered, of the same width and thickness, packed in bundles of 50-100 pieces. There should be no rot, mold, short potato pancakes in the drani.
Prior to the start of stuffing or weaving of shields, the shingles are sorted into pro-style (for stuffing the lower, pro-style rows) and output (for stuffing the upper, output rows).

Forgiveness 1 (Fig. 15, a) is laid with the first layer on the surface. To do this, use a curved and narrow shredding with a thickness of at least 3 mm, due to which voids are created between the dranitsa and the surface, under which the applied solution falls and firmly adheres to the stuffed output shredding. With a thinner peel, the adhesion of the solution to the surface is insufficient.
For the output row (Fig. 15, b), a straight, even, thick (no more than 5 mm) shreds 15-20 wide mm, since the fight is already 10 mm when driving nails into it, it pricks, and wider than 20 mm warps and breaks the plaster.
The selected shreds are laid in separate bundles.
If all the walls, partitions and ceilings are wooden, then the stuffing of the strips starts from the bottom of the walls. Having reached the top, they proceed to the stuffing of the strips on the ceiling.
The rows of the prostyle and the exit batt are placed at an angle of 90 ° to one another, and with respect to the floor - at an angle of 45 °. The stuffing of the boards at an angle of 90° gives additional rigidity to the partitions, fastening the individual boards together.
It is recommended to leave a distance of 45 between the pages of the prostyle and the output rows mm to form cells in the light 45X45 mm.
When stuffing a prostyle fray, it is only baited in the middle with one mounting nail or along the edges with two nails. They are hammered lightly so that they can only hold the shreds.
Having stuffed in height one or two rows of prostyle flaying on the walls and completely on the ceilings, they proceed to stuffing the output flaying. First, each output pancake is completely nailed with two nails only at the ends. One of the nails is hammered straight, and the second with a stretch at an angle of 45 °, while directing the tip of the nail towards the end of the cut. With this nail, the dranitsa is pulled tight. Then intermediate nails are driven in: on the walls through two prostrate pannels into the third, and on the ceilings through one.
The ends of the stacked pannels should not be connected end-to-end, but with a gap of 2-3 mm. A butt joint without a gap when wet leads to warping of the ends of the peel and swelling, which causes a tear in the plaster.
On the ceilings, the shingles are stuffed in the same way as on the walls. First, a prostrate shred is stuffed on the entire ceiling, and then a day off. The output shred is also placed at an angle of 90 ° to the prostyle.
When stuffing the wound at the bottom of the wall, its reserves are placed on the floor or placed against the wall. When the flannel is nailed at chest level, a bunch of Dranitz is placed in a special stand, which is also recommended for use when stuffing the fray on the ceilings.
The pancakes are pressed to the surface with the left hand, in the fingers of which the nails are clamped. Putting a nail to the wound, a light blow is applied to it with a hammer so that the nail holds. Then the hand is removed and more is applied over the nail. swipe and completely beat. Stuffing the output shavings, they sequentially remove the mounting nails from the prostyle shavings and use them again. The ends of the output fray must be nailed, because, when moistened, they will warp and tear the plaster.
During work, plaster nails are poured into the left pocket of overalls and several pieces are taken from it at once, clamping them with three fingers.
Nails should be hammered in quickly, with two strokes and only in the center of the pane.
plaster hammer(Fig. 16, a) weighs 450-600 G. It has two ends: sharp, bent inward with a slot in the middle, which is necessary for pulling out nails, and blunt - a butt. The butt has the shape of a flat or slightly convex square measuring 25X25 or 30X30 mm.
Handle length 280 mm. With this hammer, you can cut down reinforcing wire, beat off old plaster, and split bricks.

The plaster knife (Fig. 16, b) must have a blade up to 150 mm and a narrow end for cutting pattern profile boards. Keep the knife in a wooden case (sheath).
A stucco knife is used for splitting wide fraying, trimming edges from matting, cutting models from plaster, cutting gypsum boards and lining sheets.
For large volumes of work, in order to increase labor productivity, it is advisable to upholster the surfaces with pre-prepared lathing boards with a clear cell size of 45x45 mm or reed flexible braids with clear gaps between the rods of at least 100-120 mm.
Dranochnye boards are made on workbench-template design eng. P. A. Velichko(Fig. 17). Workbench template 5 is a table 0.7 wide and 3.2 long m. Square bosses are nailed along the edges of the workbench, between which the ends of the potato pancakes are placed, laid at an angle of 90 °. On the edge of the workbench at the intersection of the pancakes there are holes with a diameter of 30 mm.

Shields 3 made from ordinary rubbish 4 , sorted into rest and weekend. Part of the shreds are cut into pieces, which are used for laying on the corners of the shields.
First, a prostrate row is laid on the workbench, then the output row. The laid shingles are lightly knocked down with plaster nails so that their ends go out by 4-5 mm.
Nails are hammered hammer design P. A. Velichko(Fig. 18). The hammer is designed so that its striker 4 can be adjusted and driven with nails to the required depth. Nails are driven in through one or two intersections of potato pancakes.

Shields are prepared by two workers who are on both sides of the workbench.
The manufactured shield is removed, compressed to 1 - 1.2 m and placed in stacks.
For stuffing on a surface with vertically or horizontally arranged boards, the boards are applied so that the pancakes are directed at an angle of 45 ° to the floor. If the partition boards are installed with an inclination, then the shields should be placed straight, i.e., the panes should be directed vertically.
They nail the shield shit like this. The pre-stretched shield is placed against the surface and nailed with the nails that were driven into it during assembly.
Drainage boards are fixed with plaster nails 25, 30 or 40 long mm. Shields are attached to vertical surfaces through two intersections of the pancakes, to horizontal surfaces - through one intersection. The unreinforced ends of the potato pancakes are nailed additionally.
Reed braid is also fastened with plaster nails 40 long mm, placing them through 100 mm one from the other.
Fiberboard, reed, straw and other surfaces preparation is not required, since they have a roughness sufficient for strong adhesion of the plaster mortar to them. The frame located between the slabs (pillars, racks, girders) requires mandatory preparation, therefore, it is stuffed with shrapnel or nails are driven in and braided with wire or tightened with a net.
The wire and mesh should overlap the seam between the posts and slabs by 40-50 mm. In order to avoid warping and bulging, the ends of the stuffed flannel should be located on the slabs no more than 10-20 mm. For braiding with wire, nails 75-80 long are driven into the racks. mm in 20-30 mm. Drape or willow twigs are placed under the net and fastened with nails so that the net does not lie close to the tree.
In places of thick plaster marks (over 25 mm), the passage of rods and cornices drive in nails and braid them with wire or strengthen the metal mesh.
Nails should be driven into the surface so that their caps are recessed into the plaster to a depth of 15-20 mm. This prevents the plaster from rusting.
Nails are hammered, placing them in a square or checkerboard pattern at a distance of 100 mm one from the other. Nails should be 2 times longer than the thickness of the plaster coating. In partitions made of tesa, nails should not pass through.
Stuffed nails are braided with soft wire with a thickness of 1.5-2 mm. For convenience, the wire is pre-wound into a ball. During operation, the ball is held with the left hand, and the wire is tightly pulled with the right and wrapped 1-2 times around the nails at the very head.
Tightening joints of dissimilar surfaces. Mesh stuffing instead of tearing. When plaster dries, cracks always form on surfaces to be joined made of different materials, such as concrete and wood. This happens because plaster applied to dissimilar materials does not dry at the same time. To avoid the appearance of cracks, the joints of surfaces made of different materials are tightened with a mesh with mesh sizes of 10X10 or 30X30 mm. Woven mesh is cut into strips with scissors different widths, but so that it goes on both sides of the joint by at least 40-50 mm. When cutting the mesh, the hands must be held above its edges to protect them from damage.
The woven mesh is untwisted, for which one hook of the wire is unbent, grasped with tongs and pulled out. Woven mesh can only be cut to length.
It is recommended to nail the mesh to the surface before stuffing. The mesh is fastened with thick and short roofing nails, which are easily hammered into the seams of the masonry and do not bend. Nails are hammered along the edges of the mesh at a distance of 200-250 mm one from the other.
In the case of thick bastings, at the direction of the technical personnel of the construction, instead of shavings, a metal mesh is stuffed with cells no more than 40X40 mm. The mesh can be woven or woven. It is better to use wicker, as when stuffing onto the surface, the necessary roughness is formed.
The woven mesh lays close to the surface, without forming the desired roughness. In order to obtain roughness with such a grid, one should first of all fill the surface with a prolate shred with a thickness of at least 3 mm, and nail the net over the stuffed shreds. Instead of tearing, it is better to nail thin slats or willow twigs with a thickness of 5-6 mm. this achieves greater roughness.
The mesh is cut into pieces right size, nail it first with nails from one end, then pull it tightly and nail it from the other end, and then nail it to the middle, placing the nails in a square or checkerboard pattern at a distance of 100 mm one from the other. Nails are used thin, 50-70 long mm. They are clogged in half, the rest is bent, tightly pressing the mesh to the surface.
If the mesh is plastered with a lime-gypsum mortar, it should be painted with cement laitance, oil paint, asphalt or coal varnish and dried so that the mesh does not rust. It is possible to stretch and nail the mesh on the walls both in vertical and horizontal directions.
Arrangement of mesh-reinforced structures for plastering. Mesh-reinforced structures (Fig. 19) are widely used in the installation of suspended ceilings, thin reinforced concrete partitions, cornices, belts, plinths and other structural elements. Mesh-reinforced structures are diverse in shape, light in weight, and require little material.

For the device of such structures, reinforcing wire of various sections and a mesh with cells of size 10X10 are used. mm. Through such a grid, the plaster solution slips less, which contributes to the faster formation of the plaster layer. The mesh is stretched along an arranged frame of reinforcing steel.
The frame is divided into carrier and distribution.
load-bearing frame 1 holds the weight of the plastered structure (ceiling, cornice, beams), and the distribution 2 only supports the frame mesh so that it lies tightly and does not sag. The sagging of the mesh in some places increases the thickness of the plaster coating of the entire plastered surface.
The supporting frame is given the profile and shape of the future structure, for example, the shape of the cornice. If the frame is not given an exact shape, the thickness of the plaque will increase.
ends load-bearing frame they are firmly fixed in walls and ceilings, for which they drill with an electric drill or punch holes of the required depth and diameter with a jumper, into which the ends of the frame are inserted and fixed with metal wedges.
If the device of mesh-reinforced structures is provided in advance, then the ends of the reinforcing wire are inserted into the walls and ceiling, for which the supporting frame is subsequently attached.
With a device from such structures false ceiling the ends of the supporting frame are bent in the form of hooks and distribution fittings are placed on them, firmly tying it with several turns of soft wire, or welded. To prevent the frame from swinging, the ends of the distribution fittings should also be fixed in the walls.
Having arranged a frame from the reinforcement, the mesh is cut into canvases that are attached to the frame; first, one end of the web is tightly tied with wire, then the second end is tightly pulled and firmly tied. After that, an intermediate fastening of the mesh to the frame is performed. The nodes are staggered at a distance of 100-150 mm. Behind the first canvas, a second is attached, followed by a third, etc.
When constructing cornices reinforced with mesh (Fig. 20), the supporting frame is first bent in shape 1 , arrange holes for it, insert the ends of the supporting frame into the holes and firmly fix it with wedges. After attaching the distribution frame 2 cut the mesh 3 , lay it on the main frame, pull it tight and tie it.

When constructing mesh-reinforced partitions, one row of reinforcement is strengthened between the floor and the ceiling (racks are placed), the second between the walls. After that, the reinforcement is tied or welded together, the mesh is pulled tightly over the arranged frame and tied with wire. The tighter the mesh is stretched and more often tied to the frame, the less it sags and vibrates.
It is very difficult to apply a solution to a vibrating mesh, because the solution falls off from its slight vibration. The thickness of the reinforcement, the distance between the individual links of the supporting and distributing elements of the frame are indicated in the drawings or determined by the technical staff of the construction site.
Other preparatory work. Precast concrete slabs are widely used for flooring. These slabs are quite smooth, but some of them have sags and tubercles. They must be cut down or sanded with emery wheels. It is especially necessary to carefully prepare the edges of the plates in the places where they adjoin each other, on which the rustication is embroidered: a solution is applied, rubbed and cut in the form of a semicircle. The grooves should be well caulked, drowning tow or other materials in them to a depth of at least 15-20 mm.
When plastering, it is also necessary to prepare steel beams, close up grooves or channels, niches. Before laying, steel beams must be wrapped or braided with wire or tightened with a net. If this work is not done before the beams are laid, then it can be done after this operation, but before the slabs are laid. The distance between the turns of the wire should be no more than 5 cm.
If the lower part of the beam is plastered - a shelf, then 2-3 bars of reinforcement 4-5 thick are placed under the wire or mesh to form a gap mm. In cases where a wooden roll is laid on the lower shelf of the beam, and the shelf must be plastered, nails are hammered into the roll along the edges of the beam, they are braided with wire or a mesh is pulled. To form a gap from the bottom of the shelf, two or three bars of reinforcing wire are also placed.
When the wooden reel is laid flush with the bottom shelf, it is recommended to close the shelf with pro-style and output rows when stuffing the strips. Dran is nailed at the very edge of the beam. Sometimes the shelf of a metal beam is covered with insulating materials: first with felt, then with roofing felt, and after that they knock out the shreds.
If a prefabricated roll is laid on a metal beam reinforced concrete slabs and only one shelf is plastered, then nails are hammered in the gap between the shelf and the laid plates, they are braided with wire or tightened, the shelf with a mesh, placing or welding pieces of reinforcement under the mesh.
Before laying concrete slabs 1 per beam flange 2 it is recommended to hook metal clamps 4 from reinforcing wire (Fig. 21). To do this, the manufactured clamps are put on the beam shelf 2 and hammer blows compress the ends. Then the clamps are moved apart along the beam at a distance of 100-150 mm one from the other and braid them with wire 3 or tie a grid to them.

To hide heating pipes, electrical wiring, ventilation, furrows and channels are arranged in the structures. After installation work furrows and channels are closed with gypsum or concrete slabs or tightened with mesh strips, which are 100-150 mm wider than a furrow or canal. The mesh is stretched along a channel or furrow and nailed along the edges with nails (preferably roofing). Nails are driven into the seams of the masonry. In concrete surfaces, channels and furrows are recommended to be sealed with slabs.
The slabs used to seal the furrows and channels are cut to size, installed, frozen with gypsum and plastered.
Safety engineering. When preparing surfaces, it is necessary to strictly observe safety regulations, especially when electrified and impact tools are used. Improper handling of them can lead to accidents.
Before working with electrified tools, workers must undergo appropriate training on the rules of safe work.
When working with a sandblaster, workers must wear respirators. The place of work should be protected. To transfer the hoses, they are disconnected from the apparatus; hoses must not be kinked.
From all tools: chisels, trojans, gears, scarpels - the burrs must be cut down or ground off: flying away, they inflict severe injuries.
When hit with a hammer with a narrow butt on a chisel, trojan, scarpel, you can miss and injure your hand, so instead of a hammer, you should use cams in the form of small sledgehammers weighing 1-1.5 kg having wider rims. When working with impact tools, pieces of brick and concrete fly off the surfaces, which can get into the eyes or cause other injuries, so workers must wear safety goggles and gloves.
When cleaning brick, stone, concrete and other surfaces from dust and dirt, workers must wear goggles and a respirator.
It is necessary to cut the metal mesh, tighten the channels with it and pull the mesh onto the frames with mittens.