How to check the quality of plastering work? High-quality plaster: definition of the concept, applicable standards and control of work

Topic No. 42: “Quality control of plastering works. Plaster defects. Causes and their elimination"

Introduction

Currently, there are a large number of methods for engineering survey buildings for various purposes, produced by various organizations. Despite such diversity, they all have one thing general property- as a rule, they only consider issues of field surveys of building structures. This is due to the fact that in the period of the 70-90s of the last century, the customers for such work were various production enterprises and the task of field surveys was mainly to determine the condition of the load-bearing and enclosing structures of buildings. The results of such work were, as a rule, used by operational services to eliminate the emergency condition of building structures.

IN last years The volume of reconstruction and technical re-equipment of enterprises, buildings and structures has increased significantly. At the same time, one of the main tasks is saving material and energy resources. One of the features of modern field surveys is closer cooperation with technologists, designers and specialists in building engineering equipment, and the main customers and consumers of the work results are investors and design organizations. In this case, the required amount of information can be obtained only by conducting comprehensive surveys covering a wider range of issues.

In some cases, the reconstruction of buildings involves their repurposing. At the same time, a new one is placed in the existing volume of the building technological equipment, which has its own characteristics. In this case, in addition to work to determine the load-bearing capacity of the frame for new loads, it is necessary to determine the actual fire safety of the building. Carrying out such work is also necessary due to significant changes in regulatory framework, which requires identifying the compliance of the space-planning and design solutions of the building, as well as fire extinguishing systems with these new standards.

Reconstruction of a building with its superstructure or other changes in space-planning solutions also requires obtaining information about existing systems engineering equipment. This is an assessment of the state of communications, examination of thermal and energy inputs into the building, identifying the compliance of existing heat and power capacities with the proposed changes in the building.

The emergence of another new type of survey work is associated with the problem of economical use of heat and energy resources. When reconstructing an existing building, this problem is solved mainly in two ways.

First- increasing the thermal properties of enclosing structures that meet new, higher regulatory requirements.

Second- improvement of building engineering equipment systems.

Choice optimal solution reconstruction of a building with the lowest energy consumption during its operation is achieved by energy audit - carrying out thermal technical inspections of enclosing structures and engineering systems and technical and economic comparison of their effectiveness.

Comprehensive surveys of reconstructed buildings should include the following sections:

Operating environment survey;

Inspection of the condition of load-bearing and enclosing structures;

Inspection of engineering equipment systems and energy audit;

Fire safety assessment of the reconstructed building.

Based on such a wide range of issues resolved during a comprehensive survey of reconstructed buildings, the composition of survey participants also changes significantly. In this case, the survey group should also become complex, i.e. it should include specialists in studying the microclimate of premises, engineers in assessing the condition of load-bearing and enclosing structures, specialists in examining engineering equipment systems and fire safety of buildings.

1. Plaster. Purpose. A type of plaster. Quality control of plastering works

Plaster is a finishing layer on the surface of various structural elements of buildings, walls, partitions, ceilings, columns, etc., leveling these surfaces or giving them a certain form or invoice. For finishing surfaces, various types of plasters are used depending on the purpose, the material from which they are made structural elements, and the conditions in which they will be located during operation.

Purpose of plaster.

Plaster has sanitary, protective, structural and decorative purposes. Sanitary purpose plastering is to obtain even and smooth surfaces of building structures, prepared for painting and cladding, to eliminate the possibility of dust settling on them and to facilitate cleaning from contamination.

The surfaces of concrete elements of prefabricated prefabricated structures with a clean, smooth surface cannot be plastered. Protective and constructive purpose fencing plasters and load-bearing structures buildings is to protect structures from the harmful effects of dampness, increase heat transfer resistance, reduce sound conductivity, and protect against chemical substances. The plaster must satisfy the climatic conditions of the construction area, fire safety requirements, temperature and humidity conditions of the room, technological requirements production, as well as protect building structures from the effects aggressive environments. In accordance with this, a number of plasters are used special purpose- waterproofing, acoustic, etc. Decorativeness plaster consists of creating a special texture on the surface of the plaster layer by selecting the composition of the solution according to material (filler and binder) and color, the method of its application and subsequent processing of the finishing layer with various tools and devices.

The following types of plasters are most often used:

- colored- on lime-sand solutions with the addition of pigments for their coloring; their surface is processed in a semi-plastic state to match the rough and relief texture of the stones;

- stone- decorative plasters based on cement mortars with stone chips;

- terrasite- with a surface treated in a semi-dry state to create a smooth or slightly embossed structure;

Sgraffito is a two-, three- or multi-color ornamental design on a plastered surface, obtained by scratching and scraping thin colored layers of plaster.

Varieties of plaster depending on the type of surface being plastered.

Finishing various types of surfaces with plaster requires various materials and ways preliminary preparation these surfaces. Wet plaster on stone is usually done with lime or complex mortar when finishing internal brick surfaces and cement mortar on concrete surfaces with preliminary notching if the surface roughness is insufficient. In both cases, the solutions contain various fillers and additives depending on the purpose and operating conditions of the plastered surfaces. Dry plaster on stone is attached by gluing the back side of the sheets with special mastics, which are applied to the base in the form of separate adhesive marks and beacons, as well as with nails to a previously installed wooden frame or on screws to special aluminum structures. Wet plaster on wood is made from lime-gypsum mortar with additives. Sheets of dry plaster are secured to wooden surfaces with screws or thin nails with wide heads recessed into the sheet. Plaster on a metal mesh or reinforced plaster is used when it is necessary to create a plaster layer on the slope of the structure being finished and is made on the basis of a rigid metal frame for partitions, walls, metal beams, etc. Such a frame is also used when sealing furrows for hidden laying of pipelines, when creating thickened outlines over 20 mm, when finishing with plaster protruding concrete, brick and wooden architectural details (cornices, rods, corbels, etc.), when plastering joints of surfaces of structures made of dissimilar materials (wooden with brick, concrete, etc.), joints of door frames with walls and partitions. The metal mesh reinforces the plaster, which prevents the appearance of cracks along the line of such joints.

Types of plaster according to the method of execution.

All types of plaster can be divided into two groups that are fundamentally different from each other in terms of the production of work. The first, main and most common group includes wet, or monolithic plaster, the second - dry plaster. Wet plaster is created by applying a plaster solution to the surface to be treated, dry- lining the surfaces to be treated with separate sheets manufactured in special factories.

The disadvantages of wet plaster are the length and complexity of execution, the length of time it takes for the solution to harden and dry, and a large amount of moisture in the room. All this inevitably extends the period of commissioning of the facility.

The advantage of wet plaster is the monolithic connection with the plastered surface, which closes the gaps in the structure and does not create gaps between the structure and the plaster; With monolithic plaster, seamlessness is ensured, the surface can be given any shape, as well as used in wet rooms.

Wet plaster is universal and in some cases irreplaceable; it is used for finishing both internal and external surfaces. Dry plaster is more individual in relation to the execution of work: its implementation is not associated with loss of time for hardening and drying; the work may be performed by less skilled workers; subsequent finishing can begin immediately after covering the surfaces with sheets of dry plaster and sealing the seams between them. However, dry plaster is only suitable for finishing the internal surfaces of a building in dry rooms and is inferior wet plaster in terms of performance, solidity and reliability.

Types of plaster according to the degree of quality assessment.

Simple plaster performed in basements and attics of residential and public buildings, in non-permanent buildings, in temporary buildings, in warehouses and non-residential premises, where careful surface treatment is not required. Simple plaster is done under “falcon”, i.e. The layer of basting soil (except for the spray) is leveled with the edge of the falcon. The basting is usually applied in two layers - spray and soil, without hanging and checking the rule; the covering layer is not applied, but the surface of the soil is rubbed. Window corners and door slopes, pilasters, pillars are carefully leveled with a trowel. The average total thickness of the plaster marking does not exceed 12 mm.

Improved plaster usually done in residential and public buildings (schools, hospitals, kindergartens, etc.), as well as in special cases in industrial buildings and in utility rooms of high-class buildings, for plastering the facades of buildings without special architectural design. Improved plaster is carried out as follows: apply a layer of spray no more than 9 mm thick on wooden surfaces and 5 mm on stone, concrete and brick; one or more layers of soil 5 mm thick with cement mortar and

7 mm with lime and lime-gypsum mortars; covering layer 2 mm with checking the surface as a rule, without hanging the surfaces. The average thickness of the mantle is 15 mm. A covering layer 2 mm thick is rubbed with plastic, wooden or felt floats and smoothed with rubber or steel trowels. High-quality plaster is performed in buildings and structures that have high finishing requirements: theaters, museums, exhibition halls, hotels, residential buildings upgraded class, etc. The surfaces of walls, ceilings and slopes must be strictly vertical or horizontal planes.

High quality plaster They are made from a layer of spray, one or several layers of soil and a covering with hanging the surfaces and installing beacons, the height of which above the surface to be plastered determines the required thickness of the plaster mark. Beacons and stamps are made from quick-hardening solutions. The average total thickness of a high-quality plaster sheet is 20 mm.

Quality control of plastering works.

Surfaces to be plastered must be thoroughly cleaned of dust, dirt, grease and bitumen stains, and salts deposited on the surface.

Speakers architectural details, junction points of plastered structures made of different materials, must be plastered over a metal mesh or woven wire attached to the surface of the base; wooden surfaces - on shingle panels.

When performing plastering work, the following requirements must be met:

Permissible thickness of single-layer plaster:

When using all types of solutions, except gypsum - up to 20 mm;

From gypsum solutions - up to 15 mm.

The permissible thickness of each layer when installing multi-layer plasters without polymer additives:

Spraying on stone, brick, concrete surfaces - up to 5 mm;

Spraying on wooden surfaces (including the thickness of the shingles) - up to 9 mm;

Soil from cement mortars - up to 5 mm;

Soil made from lime, lime-gypsum mortars - up to 7 mm;

Covering layer of plaster coating - up to 2 mm;

Covering layer decorative finishing- 7 mm.

Deviations of plastered surfaces from the vertical (1 m):

For simple plaster - no more than 3 mm (no more than 15 mm for the entire height of the room);

With improved plaster - no more than 2 mm (no more than 10 mm for the entire height of the room);

With high-quality plaster - no more than 1 mm (no more than 5 mm for the entire height of the room).

Horizontal deviations of plastered surfaces (per 1 m):

For simple plaster - no more than 3 mm;

With improved plaster - no more than 2 mm;

With high-quality plaster - no more than 1 mm.

Deviations of window and door slopes, pilasters, pillars, husks, etc. from vertical and horizontal (1 m):

For simple plaster - no more than 4 mm (up to 10 mm for the entire element);

With improved plaster - no more than 2 mm (up to 5 mm for the entire element);

With high-quality plaster - no more than 1 mm (up to 3 mm for the entire element).

Deviations of the radius of curved surfaces, checked by a pattern, from the design value (for the entire element):

For simple plaster - no more than 10 mm;

With improved plaster - no more than 7 mm;

With high-quality plaster - no more than 5 mm.

Deviations of the slope width from the design:

For simple plaster - no more than 5 mm;

Deviations of rods from a straight line within the limits between the angles of intersection and bracing:

For simple plaster - no more than 6 mm;

With improved plaster - no more than 3 mm;

With high-quality plaster - no more than 2 mm.

Uneven surfaces with a smooth outline (per 4 m2) are allowed:

With simple plaster - no more than 3 irregularities with a depth (height) of up to 5 mm;

With improved plaster - no more than 2 irregularities with a depth (height) of up to 3 mm;

With high-quality plaster, no more than 2 irregularities with a depth (height) of up to 2 mm.

Cracks, bumps, shells, dummies, rough surfaces, and gaps on the plastered surface are not allowed.

When controlling the quality of wall finishing with sheets of dry plaster, you must be guided by the following tolerances:

– vertically at 1 m height – no more than 2 mm, and over the entire height of the room – up to 5 mm;

– horizontally for 1 m of length – up to 2 mm, and for the entire length of the room – up to 7 mm;

- for husks, appendages, slopes, pilasters and other parts per 1 m of height or length - up to 2 mm, and for the entire element - no more than 3 mm;

– along the width of the lined slope – no more than ±2 mm; the height and depth of unevenness when controlled with a two-meter strip is no more than 2 mm, sagging in the walls is 2 mm;

– the width of the sealed seams between sheets of dry plaster is no more than 6 mm.

The glued sheets of dry plaster are prepared accordingly and painted or covered with wallpaper.

2. Technical inspection of buildings and structures before major repairs and reconstruction. Plaster defects. Causes and their elimination

Reconstruction means the reconstruction of something in order to improve its functional, structural, aesthetic and other properties during subsequent operation.

To carry out reconstruction work, special technology is required, since this work is carried out in cramped conditions, sometimes in old buildings that are extremely inconvenient for this, in existing workshops. All this complicates the use of existing mechanization means, complicates the delivery of materials and structures to work sites, and prevents their normal storage in the work area. This ultimately leads to an increase in manual labor costs, and in especially cramped conditions it often causes an increased risk of their implementation.

Distinctive feature is the need for a technical inspection.

Survey – a set of measures to determine and evaluate the actual values ​​of monitored parameters that characterize the operational condition, suitability and performance of objects under inspection and determine the possibility of their further operation or the need for restoration and strengthening.

The need for survey work, its volume, composition and nature depend on the specific tasks assigned. The basis for the examination may be following reasons:

It is necessary to inspect buildings and structures damaged by accidents, catastrophes, fires, earthquakes (the purpose of such an inspection is to establish the possibility of further operation of the building and develop measures to strengthen the structures);

A reconstruction project is required, and before any reconstruction it is necessary to carry out complete information to provide designers with complete information, even in cases not accompanied by an increase in loads;

Lack of design, technical and executive documentation;

Changing the functional purpose of buildings and structures;

The need to monitor and assess the condition of building structures located close to newly constructed structures;

Redevelopment of premises (apartments, offices) is required, before designing which survey work is also required (during redevelopment, the load, location of partitions, etc. may change);

Increased operational loads and impacts on structures during redevelopment, modernization and increase in the number of storeys of a building;

Identification of deviations from the project that reduce the bearing capacity and performance structures;

Planned major renovation object;

If an increase in deformation of the building is detected (as a rule, this is the opening of cracks in the walls) and it is necessary to find out whether this is dangerous and whether further operation of the building is possible;

It is planned to resume unfinished construction in the absence of conservation or three years after the cessation of construction during conservation, for which it is necessary to clarify the current technical condition of the unfinished object (sometimes it is not practical to continue construction);

Inspection of buildings in order to monitor their condition during scheduled and extraordinary inspections;

The need to determine the suitability of industrial and public buildings for normal operation, as well as residential buildings for living in them;

You are planning to buy a building or premises in a building, and you need to find out its real condition (an inspection is strongly recommended; at today's real estate prices, a mistake can be expensive);

When creating as-built documentation for “self-construction” (as-built documentation, that is, the project, also requires a description of the current technical condition of the object), if it is necessary to carry out measurement work to draw up measurement drawings.

Technical inspection cannot be understood as something indivisible. In reality, it includes several stages.

Stages of technical inspections and scope of work. Inspection of building structures of buildings and structures is carried out, as a rule, in three interconnected stages:

Preparation for the examination;

Preliminary (visual) examination;

Detailed (instrumental) examination.

The scope of work and the sequence of actions for examining structures, regardless of the material from which they are made, at each stage include:

Preparatory work:

Familiarization with the object of inspection, its space-planning and constructive solution, materials from engineering and geological surveys (if necessary);

Selection and analysis of design and technical documentation;

Drawing up a work program (if necessary) based on the technical specifications received from the customer. The technical specifications are developed by the customer or design organization and possibly with the participation of the survey performer. The terms of reference are approved by the customer, agreed upon by the contractor and, if necessary, by the design organization - the developer of the project assignment.

Preliminary (visual) examination:

Continuous visual inspection of building structures and identification of defects and damage by external signs with the necessary measurements and their recording.

Detailed (instrumental) examination:

Work on measuring the necessary geometric parameters of buildings, structures, their elements and components, including the use of geodetic instruments;

Instrumental determination of defects and damage parameters;

Determination of the actual strength characteristics of the materials of the main load-bearing structures and their elements;

Measuring the parameters of the operating environment inherent in the technological process in a building and structure;

Determination of real operational loads and impacts perceived by the structures being examined, taking into account the influence of deformations of the soil base;

Determination of the actual design diagram of the building and its individual designs;

Determination of design forces in load-bearing structures that bear operational loads;

Calculation of bearing capacity of structures based on survey results;

Desk processing and analysis of survey results and verification calculations;

Analysis of the causes of defects and damage in structures;

Drawing up a final document (act, conclusion, technical report) with conclusions based on the results of the survey;

Some of the listed works may not be included in the survey program depending on the specifics of the research object, its condition and the tasks defined in the terms of reference.

Registration of results. Based on the results of the survey, a report is drawn up on the technical condition of the structures of the building or structure, which provides information obtained from the design and as-built documentation, and materials characterizing the features of the operation of the structures that necessitated the survey.

The final document based on the results of the inspection contains plans, sections, lists of defects and damages or a diagram of defects and damages with photographs of the most characteristic of them; diagrams of the location of cracks in reinforced concrete structures and data on their opening; the values ​​of all controlled characteristics, the determination of which was provided for in the terms of reference or survey program; results of verification calculations, if their implementation was provided for by the survey program; assessment of the condition of structures with recommended measures to strengthen structures, eliminate defects and damage, as well as the causes of their occurrence.

This list can be supplemented depending on the condition of the structures, reasons and objectives of the survey.

The technical report is signed by the persons who conducted the survey, the supervisor structural unit, technical director and executive director. The technical conclusion, which is an integral part of the technical report, is approved by the technical director.

Plaster defects.

Interior plaster

Often the plaster is made very “skinny”. It does not adhere well to the wall surface and becomes dusty if you rub it with your hand. No paint or wallpaper

stay on it (Fig. 1).

Figure 1. Wallpaper tears off the “skinny” plaster from the wall. 1 - wall; 2 - wallpaper; 3 - torn plaster; 4 - cracks; 5 - plinth; 6 - floor covering; 7 - reinforced concrete floor

The reason for this phenomenon is that it lacks a binder - lime. During hardening, the binder in the plaster mortar firmly binds the aggregate particles together, filling the gaps between them, while at the same time ensuring the adhesion of the plaster to the wall surface. If there is so little binder in the solution that the adhesiveness and adhesion are lower than that of wallpaper glue or paint, then the plaster will crack and collapse.

When plaster mortar very “fat”, i.e. it contains more binder than necessary, the plaster also turns out to be of poor quality - it cracks. Moisture penetrates into the cracks and the plaster sooner or later begins to collapse. Naturally, cracks also damage the paint applied to the surface, and it is almost impossible to repair the plaster. Excessive shrinkage of the excess lime occurs (Fig. 2).

Figure 2. Cracking of overly “greasy” plaster. 1 - cracked plaster; 2 - primer; 3 - floor covering; 4 - wall; 5 - painted surface; 6 - reinforced concrete floor

Insufficient knowledge regarding application building materials for plastering work in individual construction has already led to many mistakes more than once. For interior plastering, lime, gypsum and cement mortars are used. Each of them has its own area of ​​application, and it is not recommended to replace one solution with another.

Gypsum mortar should not be applied to a concrete surface. Cement and gypsum interact with each other chemical reaction, the plaster swells and then falls off, the gypsum penetrates the surface of the wall and destroys it. To avoid this, a 0.4 cm thick lime mortar is applied to the wall. The gypsum should not come into contact with cement or improved lime mortar. It is completely wrong to plaster over plaster with lime mortar, since when it dries, the first one shrinks, and the second one expands. At the same time, they peel off from each other and the outer layer falls off (Fig. 3).

Figure 3. Gypsum plaster cracks when applied to a lime base. 1 - surface to be plastered; 2 - lime plaster; 3 - gypsum plaster; 4 - floor covering; 5 - reinforced concrete floor

Often, interior plaster is damaged during electrical installation work. Before plastering, tubes for conducting wires or the wires themselves are placed in grooves made in the walls and secured with plaster. Wooden inserts for hooks for hanging chandeliers are fixed in the same way, since the gypsum solution quickly sets and gains the necessary strength. This method is used in electrical installation work, however, it is often used for fastening wiring without taking into account the above regarding the reactions that occur

between cement concrete walls and plaster (Fig. 4).

Figure 4. Fastening the electrical wiring with plaster mortar. a - fastening the wiring; b - fastening the hook for the chandelier; 1 - partition; 2 - gypsum solution; 3 - electrical wire; 4 - junction box; 5 - plaster; 6 - floor covering; 7 - hook; 8 - wooden insert/dowel/

When installing heating equipment, gypsum is also used to attach heating pipelines to walls or when wiring them through ceilings. The biggest mistake is made when heating pipes are laid in a wall or ceiling without casing bushings. The mason seals the holes, but the plaster only stays there until the heating starts. Under the influence of temperature, heating pipes change their

dimensions, but the plaster cannot withstand such changes and cracks (Fig. 5).

Figure 5. Movement of heating pipes causes cracks to form. 1 - cracks in the plaster; 2 - heating pipes; 3 - plastered surface; 4 - floor covering

Along with cracks from thermal expansion, when fixed with gypsum mortar, pipes begin to rust due to the fact that the gypsum absorbs moisture. This leads to rust stains appearing through the whitewash and, in some cases, to pipe failure. Application casing pipes or bushings prevent movements leading to the formation of cracks, but, however, the bushings themselves are secured with plaster. Since the bushings are made of metal, they are also susceptible to corrosion (Fig. 6).

Figure 6. Fastening heating pipes using gypsum mortar. 1 - casing sleeve; 2 - heating pipe; 3 - clamp; 4 - horizontal casing sleeve; 5 - gypsum solution; 6 - reinforced concrete floor

The plaster applied to the walls hardens and becomes durable after some time. Accelerating drying or hardening of the plaster often causes cracks and leads to its destruction. It is necessary to wait until the bottom layer of plaster hardens, otherwise after applying the second layer both of them may fall off the wall. Do not dry plaster, including central heating. This leads to its cracking and falling off. To dry the plaster, not only heat is needed, but also Fresh air, which contains what is necessary for setting carbon dioxide. If there is not enough of it, then the plaster dries out, but does not harden. If the solution also contains cement, it also cannot harden, since moisture quickly evaporates when dried. Accelerated drying of plaster is only possible with good air exchange.
When remodeling, bricks that have already been used are often used, for example, taken after the demolition of a house, after appropriate cleaning. However, if brick that was previously used in chimneys (impregnated with soot and tar) gets into the new wall masonry, then this causes various changes in the plaster, brown spots appear on the surface, damaging the whitewash and sometimes the wallpaper. The situation can only be corrected by replacing the brick. The surface of the brick wall is moistened before plastering, because the hygroscopic brick absorbs the water necessary for setting from the solution, and the plaster becomes unusable and cracks.
It is not recommended to plaster directly on a dusty surface, as dust prevents the mortar from adhering to the wall. It is necessary to either remove contamination from the surface or spray a thin layer of cement mortar (Fig. 7).

Figure 7. Plaster falling off a dusty surface. 1 - wall; 2 - applying liquid cement laitance; 3 - wall surface with cement laitance applied to it; 4 - covering the first layer of plaster; 5 - rubbed surface

As a rule, plaster adheres well to a brick wall. The concrete surface is smoother, especially if metal or wooden formwork made of planed boards, and less moisture-intensive than brick. According to technical standards, before plastering, a thin layer of liquid cement is sprayed onto the concrete surface, giving the surface the desired roughness. If this is not done, especially on a precast concrete floor, then plaster

peels off, which is unsafe for people (Fig. 8).

Figure 8. Plaster falling from the ceiling. 1 - plastered wall; 2 - unprepared surface; 3 - falling pieces of plaster

When planning houses, metal beams are often used in floors, which are treated before plastering. To do this, apply a 2-3 cm thick concrete layer on a metal mesh from below to the beam, which holds the plaster well. Internal surfaces sewer wells plastered with cement mortar. If such plaster is not provided with normal care, it will fall off. Cement plaster is kept moist for at least a week (sprinkle water on the surface or cover it with wet burlap). Cement plaster It also cracks when the surface is smoothed with a metal trowel. In this case, a crust consisting of cement alone is formed on the surface, the degree of shrinkage of which is higher than the internal layers, as a result of which it cracks and falls off. The plaster remains in place where it is constantly moistened. When remodeling a house or building up an attic, wooden surfaces are often plastered. Plaster, however, does not stick to wood and, in order to do this, you need to cover the walls with one or more

two layers of shingles (Fig. 9).

Figure 9. Plastering a wooden wall over shingles. 1 - stand; 2 - plank surface; 3 - single-layer shingle cladding; 4 - double skin; 5 - applying plaster primer; 6 - grouting the soil; 7 - grouting plaster

Interior plaster will crumble if it freezes during application or is applied to a frozen wall.

Defects in plaster can be in the form of dents, cracks, peeling, etc. and occur according to various reasons. To obtain high-quality plaster, it is necessary to take measures to eliminate these defects.
Ducts - the appearance of swollen places on the surface of the plaster. In the center of each swollen area there is a white or yellow dot, or yellow spot.
Peeling and swelling of the plaster occurs because plastering was carried out on damp surfaces or because after plastering they were subjected to constant moisture. Most often this happens on lime and lime-gypsum plasters.

The different types of cracks can be classified as follows:

Cracks caused by the condition of the plaster itself. In this case we're talking about about cracks that occur exclusively in the plaster layer as a result of an unfavorable ratio of stresses and loads. In this case, the plaster may crack throughout its entire thickness, or a crack may form only in its very top layer. Such cracks do not have any particular dynamics and are therefore characterized as “static” (non-developing) cracks.

Cracks caused by the condition of the base under the plaster. Such cracks occur in the base as a result of deformation. In this case we are also talking about cracks that arose due to internal stresses. Since the reasons lie in base defects under the plaster layer, such cracks are characterized as “conditionally static” (dynamically developing under the influence of external factors).

Cracks caused by the structure of the building. Here we are talking about developing cracks that arise as a result of settlement and movements of the structure itself. Such cracks may occur due to changes environment. For this reason, such cracks should be classified as “dynamic” (heavily loaded).

Depending on the big picture There are different types of cracks:

Microcracks. Microcracks are characterized as chaotically located cracks, indistinguishable to the naked eye. Such cracks form only in upper layers coatings, most often due to shrinkage of mineral components or when applying paint and varnish coatings at high temperatures, do not penetrate the entire depth of the coating and do not reach the underlying layers. Since microcracks do not extend through the entire depth of the coating, they do not violate the technical and physical characteristics of the material.

Hairline cracks. Hairline cracks are characterized primarily as chaotically located, arising as a result of material aging, exposure to atmospheric loads under conditions of temperature changes, moisture, and thermal deformation during operation. When moisture gets into such cracks and with further freezing/thawing, they progressively open and increase in length. In the absence of timely repair measures, this type of static cracks can develop into conditionally static ones.

Dead end cracks. Dead end cracks are characterized primarily as horizontally running (downward bending) cracks. In the area of ​​the lower edge of the crack, voids may form.

Dead-end cracks occur in a plastic, not yet hardened layer, namely:

When applying too thick a layer of plaster (in one pass);

If the plaster coating has poor adhesion to the base;

If the plastered surface is grouted for too long and intensively;

If the consistency of the plaster solution is too soft.

Shrinkage cracks type A. Shrinkage cracks are a grid with a distance between “nodes”. The reason for the occurrence of such cracks is the incorrect composition of the plaster, a violation of the plastering technology. When using modified plasters, such cracks may appear due to a low concentration of cellulose ethers in their composition or due to an increased cement content.

Type B Shrinkage Cracks Type B shrinkage cracks also appear as a network or appear as branches and are designated as "Y" cracks. Such cracks can reach the base. Such cracks can occur if:

The substrate and plastering system are incompatible;

There is a layer on the base that prevents the plaster materials from setting;

There is incompatibility of materials within the plaster coating system;

The holding period (curing time) is not observed;

Excessive dehydration of individual layers or the entire coating due to heat, sun exposure, wind or highly absorbent substrates.

Diagonal cracks in the corners of openings. This type includes cracks, usually running diagonally from the corners of building openings. The reason for the occurrence of such cracks lies in the fact that in the corners, due to openings, which are one of the most loaded areas of the building, other sections of the base are ruptured.

Cracks in joints and seams. As the name itself suggests, these cracks represent a uniform pattern of cracks located at the points of connection and filling of panel joints or in the masonry seams of the enclosing structure, and are identical to them in the form of formation.

The most important reasons for the occurrence of this type of crack are as follows:

Deformation of the outer surface of large-format blocks or panels as a result of thermal effects and moisture, which are not covered with plaster for a long period of time. The reason for this is that the modulus "E" (modulus of elasticity) of the plaster is too high and too high level strength;

Greatly different properties of masonry materials and/or joint filler (mixed masonry);

Changes in the thickness of the plaster layer over the gaps of brick or panel masonry due to poor filling of support and connecting seams.

Causes and their elimination

There are various reasons for the formation of cracks. Cracks can occur:

Due to hardening of the cementitious material or its accumulation on the surface (formation of an iron layer) during application;

If there is a mismatch between the strength level and the application area or due to a violation of the particle size distribution curve, e.g. during application mechanically when light impurities are ground;

Due to shrinkage and swelling of the base under the plaster layer, for example, with mixed masonry or when using building materials that, when absorbed, large quantity moisture swells especially strongly;

Due to thermal swelling and shrinkage of the base under the plaster, if materials with different thermal conductivities(for example, at the border of mixed masonry);

As a result of movements of the soil foundation (building soil) or the load-bearing foundation of the building (for example, the so-called settlement of the structure); in this case we are talking about particularly serious cracks, which should be addressed during repairs Special attention;

Due to the specifics of the material itself (for example, in mineral decorative plasters).

Whenever any deformation occurs, internal stresses arise that exceed the internal strength of the plaster coating, and the likelihood of cracks in the coating is especially high. In this case, the accumulation of binder on the surface, the discrepancy between the strength of the materials and the area of ​​application, severe swelling of the base under the plaster as a result of thermal effects or penetration of moisture and its shrinkage, as well as improper preparation of the base for the plaster are of significant importance.

Cracks, peeling and voids resulting from surface swelling and excessive internal stress in very hard plaster at the masonry boundary.

Accurate characterization and classification of cracks in plaster is a particularly important issue, since the results of this assessment will determine the possibility of their repair. Based on the general picture of the defect and the shape of the cracks, it is possible to draw a conclusion about the reasons for their occurrence in order to correctly classify the cracks in the future and propose appropriate measures to eliminate or repair them.

Table 1 shows plaster defects and methods for eliminating them.

Table 1. Plaster defects, reasons for their occurrence and methods of elimination

	Reasons for their appearance	Preventive measures and solutions
Dutics on the surface	Presence of small particles of unslaked lime in the solution	Keep the lime dough until the lime is completely slaked. Mix the solution thoroughly. To correct it, beat off and clean the damaged areas where linings have appeared, and seal them with mortar flush with the surface of the plaster.
Insufficient strength	Weak mortar due to insufficient quantity or poor quality of binder or high sand contamination	The compositions and brands of solutions, depending on the type of surfaces, the purpose of the premises and air humidity during their operation, must correspond to the accepted data. The quality of the sand must comply with GOST 8736. Insufficiently strong plaster, identified after tapping, is beaten off with a percussion tool, cleared and the surface is plastered again with a high-quality solution with appropriate preparation of the base
Cracks on the surface	Using solutions that are too greasy or poorly mixed	When preparing solutions, dose binders and fillers correctly and mix them well
	Rapid drying of plaster under the influence of strong draft winds and high temperatures. Applying thick layers of mortar over freshly applied unset mortar	Eliminate drafts when plastering surfaces and maintain normal temperature regime. The thickness of each layer of soil should not exceed 7 mm for lime and lime-gypsum mortars and 5 mm for cement mortars. Apply the solution only to well-set previous layers.
	Absence metal mesh or weaving wire over nails at the junction of structures made of dissimilar materials	Nail strips of metal mesh at the junctions between the wooden parts of buildings and brick, concrete or gypsum concrete structures. To fix it, open up the cracks and cracks, moisten these areas well with water, coat them with the solution and rub them in. In places where structures made of dissimilar materials meet, beat off the plaster, clear these places, nail down strips of metal mesh or braid with wire over nails and plaster again
Swelling and flaking	Plastering on damp surfaces or constant moistening after plastering, especially when using lime and lime-gypsum mortars	Before plastering, damp areas must be thoroughly dried. To correct this, knock off the plaster in areas of swelling, clear these areas and plaster them again
Rough surface	Applying a covering layer from a solution prepared on coarse sand	For the covering layer, use a solution prepared with strained lime and sifted sand. Strain the covering solution. To correct, rub the plaster with a solution prepared with fine sand and strained through a sieve with 2 mm holes.
Peeling	Applying the solution to a contaminated or dry surface not wetted with water, or to dried layers of a previously applied solution	Thoroughly clean the surfaces of brick, concrete and other structures from dust, dirt, grease stains, as well as salts protruding on the surface, and moisten with water. Apply subsequent layers of plaster coating immediately after the previous layer has set, if the latter is made of lime-gypsum, lime-cement or cement mortar, and after whitening the previous layer made of lime mortar
	Subsequent layers of mortar are applied to the less durable previous ones	Apply subsequent layers of mortar on top of the stronger previous ones. To correct, beat off the peeling plaster, clean thoroughly in compliance with the above conditions
Surface irregularities	Plastering was carried out without checking the surface according to the rule	Check the surface with a rule of 2 m in length. In places of recesses, apply additional spray and rub it. Clean off the bumps with a trowel, spray and rub.
Grainy surface texture and circular stripes	The grouting of the spray was done poorly. The solution is prepared using coarse, unsifted sand.	Make an additional spray on the cover from a solution prepared on fine sifted sand and rub the surface.
Shells on the surface	Preparation of a solution using unslaked lime	Wet the surface with water several times over two weeks. After the surface has dried, spray it and rub it in.
Fat and rust spots	Contamination of the mortar, dry plaster nail heads are not oiled.	Clean stained areas to the full depth of the plaster layer and plaster again; Clean the nail heads from rust and dry them.

3. Expert inspection of buildings and structures

Expert inspection of buildings consists of the following stages:

Preparatory, general and detailed inspection of the object;

Calculation of strength, stability and deformation of load-bearing structures and buildings and structures as a whole;

Preparation of a technical report.

On preparatory stage it is necessary to study archival materials, the standards by which the design was carried out, and collect initial data and illustrative materials.

The initial data for performing the work is:

Technical specifications with a certificate about the expiration of the estimated service life of the building;

Inventory floor plans and technical certificate on the building; in the absence of these materials, a specialized organization must carry out measurement drawings;

Certificate of the last general inspection of the building performed by the maintenance service (the absence of a report is not a reason for non-fulfillment of work);

Information about the construction site (subsidence soils, presence of part-time work, etc.), if such data is not available, the organization conducting the survey must obtain it independently;

Geobase made by a specialized organization (the absence of these materials increases the amount of work to determine the properties of foundation soils).

A general survey is carried out for a preliminary acquaintance with the building and drawing up a program for a detailed inspection of the structures. During a general examination, the following work must be performed:

Establish a structural diagram of the building and identify the location of load-bearing structures in plan and height;

Perform a thorough inspection and photographing of roof structures, door and window blocks, stairs, load-bearing structures, facades;

Mark the locations of excavations, openings, and sounding of structures to obtain reliable (at a level of at least 0.95) data;

Study the features of nearby areas of the territory, vertical layout, state of landscaping of the territory, organization of allotment surface waters;

Determine the presence of filled-in ravines, landslide zones and other dangerous geological phenomena near the building;

Assess the location of the building in the development of neighborhoods from the point of view of support in smoke, gas and ventilation ducts.

A detailed examination is carried out to clarify the structural design of the building, the dimensions of elements, the condition of materials and structures as a whole.

During a detailed examination, work should be carried out to open structures and joints with measurements, taking samples, checking and assessing deformations, testing selected samples, to determine the physical and mechanical characteristics of structures, materials, soils, etc. All types of work must be carried out using tools, instruments, and testing equipment.

Calculations of strength, stability and deformability of individual structures and the building as a whole, taking into account their actual condition, make it possible to identify existing reserves of bearing capacity and make a forecast of the duration of trouble-free operation.

If the inspection reveals the presence of freezing and wet spots in the walls of the building, then it becomes necessary to perform thermal engineering calculations. The results are taken into account when developing recommendations for repair activities.

The technical report on the expert examination must contain:

List of documentary data on the basis of which it was compiled;

History of the building;

Description of the surrounding area and construction site;

Description general condition external inspection of buildings with photographs of facades and damaged structures;

Drawings (including measurements) of plans and sections;

Marking drawings of structures indicating the locations of openings;

Defective records of all structures and locations of openings, indicating the amount of physical wear and tear;

Thermal calculations (if necessary);

Calculation of operating loads and verification calculations of the base, foundations and load-bearing structures;

A diagram of the building and site plan with pits and wells, sections of pits and wells;

Geological and hydrogeological conditions of the site, construction characteristics soils, information about seismicity and displacement trough;

Determination of the physical deterioration of the building as a whole;

Analysis of the causes of the emergency condition of the building, if any;

Building foundations have physical wear of 60% or more if signs of wear are characterized by the following defects:

Curvature of horizontal lines of walls;

Settlement of individual areas;

Distortions of window and doorways;

Complete destruction of the base;

Significant heaving of the soil.

Examinations determine the presence of these defects, and the following work is performed:

Soil exploration by drilling;

Opening of control pits;

Checking the presence and condition of waterproofing;

Laboratory analyzes of soil and water, laboratory studies of foundation materials;

Verification calculations of the bearing capacity of bases and foundations.

In accordance with SNiP 2.02.01-83*, SNiP II-22-81 and SNiP 2.01.07-85* loads and impacts transmitted to the foundation by building foundations are established taking into account collaboration building and foundation structures.

Number exploration wells determined according to table 6SN RK 1.04-04-2002.

Test pits for examining the structure, dimensions, and material of foundations are installed 2…3 per building. The pits are torn off from the outside or inside depending on the convenience of opening.

The pits are dug 0.5 m below the base of the foundation. If bulk, peaty, loose or other weak soils are found at this level, a well should be drilled in this place to determine the thickness of the soft soil layer.

Minimum size pits are determined according to Table 7 SN RK 1.04-04-2002.

The length of the exposed foundation must be at least 1 m.

Inspection of foundations and foundations within the opened pit is carried out as follows:

The type of foundation, its plan form, dimensions, depth, previously completed reinforcements, as well as grillages and artificial foundations are established;

Examine masonry with definition mechanical method brands of stone and mortar;

Samples of soil and masonry material are taken for laboratory testing;

Establish the presence of waterproofing.

To determine the physical and mechanical characteristics of soils, it is necessary to select rocks with disturbed and undisturbed structure. At the same time, the density, volumetric mass and soil moisture are determined in laboratory conditions. If necessary, hygroscopic humidity, porosity, particle size distribution, plasticity, water resistance, etc. can also be determined.

Physical wear and tear of brick, stone and wooden walls is estimated at 61% or more if their condition is characterized by the following features:

Noticeable curvature of horizontal and vertical lines of walls;

Mass destruction of masonry, blocks or panels;

Availability of temporary fastenings;

Deviation of columns from the vertical is more than 3 cm;

Bulging more than 1/50 of the height of the room;

Weathering of seams to a depth of more than 40 mm;

Cracks and peeling of the protective layer, corrosion and sometimes ruptures of reinforcement reinforced concrete columns;

Rotten damage to wooden walls.

During a detailed examination of walls, columns and load-bearing partitions, the following is carried out:

Description of identified structural defects and their assessment;

Mechanical definition strength of the construction material;

Laboratory testing of material strength;

Verification calculation of structural strength from the effects of operational loads;

Thermal engineering calculation.

Verification calculations of the strength of structures are carried out in accordance with SNiP II-22-81 for bearing capacity, for the formation and opening of cracks, and deformations.

The material of stone walls is determined by control probing. For this purpose, bolts with a diameter of 16...20 mm and electric drills are used.

The strength of the wall material at the inspection site can be determined using Fizdel, Kashkarov hammers or the TsNIISK device. Tapping walls, in addition to determining strength, makes it possible to determine the quality of adhesion of the brick to the mortar, determine areas of chipping of the mortar and the mobility of the brick.

The number of samples for laboratory testing of wall material is established depending on the size of the building (Table 9 SN RK 1.04-04-2002).

Signs characterizing wear of 60% or more of precast reinforced concrete floors, floors made of double-shell rolled panels and precast concrete flooring, wooden floors, the following:

Deflections, in some places the concrete of the lower slabs is falling off;

Peeling and exposure of the ribs of the upper slabs;

Multiple deep cracks in slabs;

Displacement of slabs out of plane;

Deflection of double-shell reinforced concrete panels is more than 1/50;

Deflections of reinforced concrete floorings are more than 1/80, prefabricated and monolithic solid slabs are up to 1/100;

Deflections of monolithic and prefabricated reinforced concrete and metal beams are more than 1/150;

Corrosion of reinforcement more than 10% of the cross-section;

Reducing the cross-section of beams by more than 10%;

Severe damage to wood by rot;

Deflection wooden beams and runs.

During an instrumental examination, a preliminary inspection is carried out to establish the material and structural design of the floors, and visually determine the locations of deformations.

Definition of reinforcement section reinforced concrete structures, the location and cross-section of metal elements in vaulted ceilings are performed using ISM devices or a ferroscope.

During the examination the following should be determined:

Locations and dimensions of load-bearing structures;

Span of beams and purlins, distance between them.

The strength of the floor material is determined on samples by laboratory analysis, as well as during examination with a Fizdel and Kashkarov hammer, a TsNIISK pistol and a UKB-1 ultrasonic device.

Verification calculations of floors are carried out to establish the actual stresses in the structural material caused by existing loads, taking into account operating conditions and the actual strength of the material. Depending on the material of the floor structures, the calculation is performed in accordance with SNiP 2.03.01-84*, SNiP II-23-81* and SNiP 2.01.07-85*.

If necessary, test load tests can be carried out to determine the strength characteristics of floor elements.

The loading scheme in each case is assigned in accordance with the structural diagram of the floor. The structure is loaded with a control load qk. The load from its own weight is calculated based on the volumetric weight of the structure material, which is determined in the laboratory, and an overload factor of 1.1 is added to the calculated weight.

Live load q BP is accepted with a reliability factor equal to 1.2...1.3, based on current standards loads for this type of premises in accordance with SNiP 2.01.07-85*.

Floor deflections are determined by a P-1 deflection meter, as well as a level with special nozzle.

To determine the strength characteristics of the floor material, openings are carried out, the number of which is assigned depending on the area being examined (Table 16 SN RK 1.04-04-2002).

Balconies (loggias) with slab deflections of more than 1/100 of the span, cracks of more than 2 mm, and bulging of walls of more than 1/150 of their length are classified as emergency structures.

During instrumental inspection of balconies, the following is carried out: preliminary inspection, performing autopsies, establishing the nature of deformations, testing structures with a test load, and performing verification calculations. Depending on the material of the balcony structures, the strength and deformability of their elements are calculated in accordance with SNiP 2.01.07-85, SNiP 2.03.01-84*.

If necessary, tests of balconies are carried out with a test load in the same way as tests of floors. In this case, the design diagrams of the balconies and the stresses that depend on them, arising in the supporting structures from the existing loads, are taken into account.

Instrumental examination of roof elements is carried out similarly to methods for examining floors; if there are cracks in building trusses or balconies of more than 2 mm, deflections of slabs or beams of more than 1/100, damage to slabs over an area of ​​more than 20%, the roof is assessed as unsafe. During the inspection, the type and material of load-bearing structures are determined, a laboratory analysis of the strength characteristics of the material of load-bearing structures is carried out, and verification calculations of stresses in roof elements from existing loads are performed.

In the presence of deflections up to 1/150 of the span, local destruction, cracks in the joints of the flight slabs, deflections of steel stringers with weakening of their connections with the platforms, destruction of notches in wooden staircase structures, rot wooden elements The condition of the stairs is classified as emergency. During the instrumental examination of stairs, visual inspection load-bearing structures, if necessary, an autopsy is performed, samples of materials are taken for laboratory analysis, and a verification calculation is performed.

The deflection of the supporting structures of stairs is determined by a deflection meter P-1, as well as a level with a special attachment. The obtained measurements are compared with the maximum permissible deflections established for the emergency condition of this structure.

The work on the study of wooden load-bearing structures includes determining the quality of wood by drilling with an electric drill or a hollow auger, which allows you to remove a column of wood to judge the change in color, strength of the wood, as well as to determine the boundaries of damage.

The method for determining deformations of the bases and foundations of buildings includes the following work.

Before starting work, an on-site reconnaissance is carried out.

The purpose of reconnaissance: to collect information about the condition of structures, the presence and nature of cracks; outline the location and design of lighthouses; identify the causes of deformation.

Based on the results of the reconnaissance, the following should be drawn up:

Brief characteristics of the household and building;

Description of the characteristics and condition of soils;

Description of locations for laying geodetic signs, justification for their choice;

Approximate diagram of the planned measuring network;

Presence of cracks and places where beacons are installed.

After this, a work program is drawn up to determine the deformations of the bases and foundations of buildings.

Working programm consists of a brief explanatory note, to which is attached a work schedule.

IN explanatory note are indicated:

Goals and objectives of observations;

Engineering-geological conditions of the foundation;

The number of designed signs and their type for measuring deformations;

Instruments and methods of measurement;

The procedure for processing measurement results;

Drawing up a report on the results of observations.

Observation of settlements and deformations of bases and foundations is stopped if, during three measurement cycles, their value fluctuates within the specified measurement accuracy.

Measurements of vertical movements (settlement, rises, etc.) are divided into three classes, which are characterized by measurement accuracy - the value of the root-mean-square error from two measurement cycles:

for class I + 1 mm;

for II class + 2 mm;

for III class + 3 mm.

For a building built on compressible soils, settlements and subsidence are measured with class II accuracy.

The placement, design and installation of initial benchmarks is carried out as follows:

Before starting work on measuring sediment, a ground geodetic mark is installed below the freezing depth;

The ground benchmark can be metal or reinforced concrete; if there are metal or reinforced concrete structures near the building with a laying depth below soil freezing, they can be used as ground benchmarks;

It is possible to use benchmarks embedded in the walls of neighboring buildings;

The number of ground benchmarks is at least three, the number of wall benchmarks is at least four;

When laying wall markers, it is necessary that the buildings do not have visible deformations and were built 5 or more years before the markers were laid.

The placement, design and installation of marks is carried out in accordance with the following requirements:

The marks are installed approximately at the same level, placing them at the corners of the building, at the junction of the transverse and longitudinal walls;

The locations of the marks are indicated by conventional signs (for example -) on the building plan, made on a scale of 1:100...1:500;

Each stamp is assigned a number.

Measuring settlement by geometric leveling of class II should be performed:

The leveling move begins with a benchmark and ends on it or on another benchmark; the number of stations in a hanging passage is not allowed to exceed 2;

The length of the sighting beam should not exceed 20 cm; the height of the sighting beam must be at least 0.5 m above the ground;

After completing a closed move, its discrepancy is calculated; it should not exceed the permissible discrepancy fn.

The measurement results are processed as follows:

At the end of the field measurements, the excess between the marks and benchmarks is calculated and a diagram of leveling moves is drawn up, on which the calculated excesses, the obtained and permissible discrepancies are written down; Rounding is done to the following values:

Exceeding 0.1 mm;

Markings 1 mm;

Draft 1 mm;

The foundation settlements under each mark are calculated as the difference between the mark's mark obtained in the last measurement cycle and the mark obtained in the first cycle;

On the foundation plan, under the number of each brand, write the amount of its settlement in mm;

Based on the sediment report, statements of average weekly and average monthly precipitation rates are compiled;

Under natural conditions, hydrostatic leveling is used to determine sediment.

Crack observations are carried out observing the following conditions:

A beacon is installed on each crack at the point of greatest opening;

Observations of cracks are carried out until their opening ceases; at each inspection, mark the position of the end of the crack with a stroke applied with paint or a sharp instrument; next to each stroke the date of inspection is indicated;

The location of cracks is shown schematically on the drawings. general view;

For each crack, a schedule of its opening is drawn up;

A report is drawn up for cracks and beacons in accordance with the inspection schedule; the act specifies:

Date of inspection;

The names and positions of the persons who carried out the inspection;

Drawings with the location of cracks and beacons;

Information about the condition of cracks and beacons during inspection and replacement of destroyed beacons with new ones;

Information about the absence or presence of new beacons.

List of basic literature

3. SN RK 1.04-04-2002 Inspection and assessment of the technical condition of buildings and structures. – Almaty: “KAZGOR”, 2003. – 68 p.

4. MDS 13-20.2004. Comprehensive methodology for inspection and energy audit of reconstructed buildings. – M.: Gosarkhstroykontrol, 2000.

5. MRR - 2.2.07-98 Methodology for conducting inspections of buildings and structures during their reconstruction or redevelopment. – M.: State Unitary Enterprise “NIAC”, 1998. – 28 p.

12. RDS RK 1.04-07-2002 Rules for assessing the physical deterioration of buildings and structures. – Almaty: “KAZGOR”, 2003.

17. RDS RK 1.04-15-2004 Rules for technical supervision of the condition of buildings and structures. – Almaty: “KAZGOR”, 2005. – 17 p.

28. GOST 5802-86 Construction mortars. Test methods. - M.: Standards Publishing House, 1986.

1. To check the strength old plaster When dry and damp, scrub it with a wire brush.

2. To check the hardness of the old coating, run the flat side of a screwdriver across the surface, pressing firmly on the screwdriver.

3. If deep scratches remain on the surface, then the old plaster must be removed.

How to determine the presence of voids under an old plaster coating?

4. The entire surface should be carefully checked, especially in areas of cracks.

5. Tap the surface with a hammer or metal rod; in void areas the sound will be muffled.

6. In places where there are voids, remove old plaster

How to determine the type of old plaster coating? How to determine what walls are plastered with?

7. In order to understand whether the old coating is compatible with the new one, it is necessary to determine its nature - mineral or polymer.

8. Under the influence of flame:(such as a blowtorch) polymer coatings soften or crack, and polymer binders emit a specific odor.

9. Mineral plasters (lime-cement, cement) do not react to exposure to flame.

How to check the adhesion strength of polymer plaster or paint?

10. If the old coating (plaster or paint) is not intended to be removed, it is necessary to check the strength of its adhesion to the base.

12. The adhesion strength of paints or polymer plasters to a rough surface can be checked using a spatula or knife.

11. On an area measuring 10x10 cm, apply horizontal and vertical scratches in 2 mm increments. If >80% of the paint is retained, the adhesion strength is considered sufficient.

How to find out the adhesion strength of new plaster to the old coating (paint or plaster)?

When the surface is covered with polymer paint or plaster, you need to know how strong their adhesion is to the new plaster.

13. Cement-lime plaster may not have sufficient adhesion to polymer plaster or paint (saponification).

14. Apply a layer of plaster to the surface of the old coating and insert a 50x50 cm mesh into it so that the edge of the mesh is not covered with mortar. Allow to dry for 3-4 days.

15. If the solution remains on the surface when the mesh is torn off, the adhesion strength is sufficient. If fresh mortar or old coating is removed along with the mesh, then the adhesion is weak, the old coating must be removed.

How to determine the absorbency of a substrate?

16. This must be done to determine:
. what primer should be used.
. Is it necessary to use a special solution with increased adhesion?

17. Wet the base with bottled water.
1) water is quickly absorbed, the stain quickly increases. Treat the base with primer at least 2 times.
2) water is absorbed, the stain slowly increases. Treat the base with a primer.

18.

3) water, slightly absorbed, wets the surface. It is necessary to treat the base with a primer.
4) water flows freely from the surface without wetting it. It is necessary to treat the base with a primer.

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Often the project, estimate, technical task and other documentation related to renovations in a house or apartment contain such a concept as “high-quality wall plaster.” As a rule, documents do not have a definition of a term meaning a specific set of operations.

This often leads to a misunderstanding of the essence of the work and, as a consequence, to further conflicts between the customer and the work manufacturer. Only an accurate idea of ​​the level of quality of future work will allow you to avoid problems when renovating your home. This article will help you with this.

Finish classes

Russian SNiP No. 3.04.01/87 “Finishing and insulating coatings” defines three types of plaster finishing according to its quality:

• simple;
• improved;
• high quality

Note! The standards and requirements for the quality of plastering work stated in the document are applicable both for self made, and mechanized. Each class of plaster requires compliance with certain rules.

They regulate the maximum permissible deviations from the design values ​​or conditions that are accepted between the parties in the relationship, by default.

Plaster layers

Before we move on to describing the types of plaster by quality, let's talk a little about finishing layers. This is important for understanding the essence of the topic.

First, the base is sprayed.

1. Its purpose is to ensure reliable adhesion to the surface of the walls of the following layers. For spraying, a solution with a liquid consistency is used. This makes it possible to fill in unevenness in the base, ensure strong adhesion, and hold all layers of plaster. Layer thickness 0.3/0.5 cm.
2. At the second stage of work, primer is applied. It is necessary for the basic alignment of the plane of the walls. When priming, a solution having a dough-like consistency is used. Its thickness can be 1/2 centimeter.
3. Third layer - cover. It is needed to level out small defects and smooth out the coating. A solution with a creamy consistency is used for it. The layer thickness should be 0.2/0.5 centimeters.

Note! When plastering any type, if the totality of all its layers exceeds 2 centimeters, the base surface must be pre-reinforced. This can be done using a metal or polymer mesh.

Types of plaster by quality

1. A simple type of finishing is used in basements, utility rooms, warehouses, and attics. In other words, in all non-residential rooms where an absolutely flat wall surface is not required.
2. Improved plaster is needed in rooms that are directly used by people. These can be residential buildings and apartments, medical, public, educational institutions etc.

1. High-quality plaster is used for work in public, residential, medical, educational, office buildings, with increased coating requirements. In other words, when project documentation directly indicates the similar nature of the rough cladding.

SNiP defines the following features of plaster coating classes.

1. A simple type of finish should consist of two mortar layers - spray and primer. Their total thickness should be 2 centimeters.
2. The improved coating is applied in three layers and consists of spray, primer and cover. The total thickness of the finish should be about 5 centimeters.
3. A high-quality grade of plaster consists of four layers - spray, two primer layers and a topcoat. The total thickness of such finishing should approach 2 centimeters.

Note! The instructions say that the application of improved and high-quality plaster must necessarily be carried out along the guide beacons. They are installed on the walls before the main work and can be made from mortar or in the form of ready-made metal profiles.

A high-quality class of plaster is intended for leveling and smoothing bases for their further finishing:

• various paints and varnishes;
• wallpapering;
• facing with ceramic, porcelain stoneware, clinker, plastic tiles.

Quality control of this type of plastering work, carried out according to the minimum permissible SNiP deviations, makes it possible to carry out finishing finishing work at the highest level.

It should be remembered that the optimal order of performing the described operations is as follows.

1. First of all, the ceiling is plastered. Next, the walls are processed in the top/down direction. Floors should be leveled last.
2. Plaster mortar can be applied to the surface of the base in two ways: spreading it or throwing it on.

Related articles:

Requirements for quality finishing

Deviations that are permissible in terms of the quality of plastering work are given in tables No. 9 and 10, SNiP No. 3.04.01/87.

Permissible deviations during work

1. The difference in the plane of the walls from the vertical per 1 meter of their length is 1 millimeter. For the entire height of the room - no more than 5 millimeters. The planes of the walls from the horizontal, per 1 meter of their length - 1 millimeter
2. When carrying out work with your own hands, keep in mind that the finishing surface can have no more than two irregularities of smooth outlines per 4 square meters. Their depth or height should not exceed 2 millimeters.
3. Deviations of door and window slopes, arches, pillars, pilasters from the horizontal and vertical should not be more than 1 millimeter.
4. The radii of curved elements and surfaces should not deviate from the design value by more than 5 millimeters. The question arises - how to check the quality of plastering work in this case? This must be done using a pattern template.
5. The width of the slopes should not deviate by more than 2 millimeters from the design value.
6. Deviations of the rods from the straight axis, between the angles of their intersection and bracing, cannot be more than 2 millimeters.

Characteristics of coating and base

The moisture level of stone, concrete and brick walls when plastering them should not exceed 8%. The adhesion strength of plaster mixtures (in MPa) during interior work must be at least 0.1. When performing external plastering work, this value cannot be less than 0.4.

Below is the permissible thickness of each finishing layer when laying multi-layer coatings (without the use of polymer modifiers).

1. Thickness of spray on concrete, stone and brick foundations– no more than 5 millimeters.
2. The amount of spray on wooden surfaces (including the thickness of the shingles) is no more than 9 millimeters.
3. The soil, consisting of a cement-sand mixture, should have a thickness of no more than 1/2 centimeters.
4. The primer layer, laid from lime, gypsum or lime-gypsum mortar, should not exceed 0.7/1 centimeter in thickness.
5. The covering of the rough plaster finish should be 0.2/0.5 millimeters.
6. The covering layer of decorative coating should not be more than 7 centimeters.

Note! Important information How to check the quality of wall plaster. After completion of work, the surfaces should be inspected. They should not have coating peeling, cracks, deep scratches, efflorescence, cavities, or obvious traces of troweling tools.

Requirements for the quality of materials

These provisions are voiced in GOST No. 28013/98. " Mortars", in the section "General technical. conditions".

Also, the requirements for materials for high-quality plastering are given in table No. 8 of SNiP No. 3.04.01/87.

Prepared yourself or purchased ready-made at a concrete plant plaster mixture must meet the following specifications.

1. The solution intended for spraying and priming must pass through a sieve with a mesh cross-section of 3 millimeters. The mixture for covering or single-layer plaster should pass through cells measuring 1.5 millimeters.
2. The solution should have a mobility in the corridor of 5 to 12 centimeters.
3. Its level of delamination should not exceed 15%.
4. Magnitude water holding capacity the mixture must be at least 90%.
5. The strength of the coating must correspond to the value included in the project.

The plaster mixture must be mixed with sand having a fractional modulus of 1/2. Solutions for spraying and primer should not contain grains larger than 2.5 millimeters.

Sand for covering should have a particle size of no more than 1.25 millimeters.

The plaster mixture purchased at the factory must be accompanied by a document confirming its quality.

It states the following:

• the date of year and time (in hours and minutes) of preparing the solution;
• brand of mixture;
• type of binder;
• scope of supply;
• solution mobility;
• the state standard is given;
• the price of a cubic meter of solution and its specific delivery are indicated.

Carrying out work in accordance with the regulatory document

Requirements for the implementation of high-quality plastering work are stated in paragraphs No. 3.1/3.17 of SNiP No. 3.04.01/87.

Surface preparation

Before plastering begins, the following operations must be carried out.

1. The premises to be finished must be protected from weather influences and precipitation.
2. There is hydro-, heat- and sound-insulation of surfaces, as well as leveling floor screed.
3. The joints and seams between the panels and blocks are sealed.
4. The junction areas of door and window units, as well as balcony blocks, have been sealed and carefully insulated.
5. Windows installed.
6. Embedded elements have been installed.
7. Test runs of the heating and water supply systems were carried out.

Main works

1. Plastering should be carried out at a temperature of air and the surface being treated not lower than +10°. Air humidity should be no more than 60%. This temperature must be maintained in the premises at all times, no less than two days before the start and twelve days after completion of the work.
2. Plastering should be carried out on the basis of the PPR - the work plan for the construction of a building or structure.

Note! Apply plaster finishing on surfaces that have areas with efflorescence, rust, bitumen and grease stains, it is strictly prohibited. It is necessary to remove dust from the base before laying each layer of plaster.

1. The strength of the treated surfaces should not be less than the same finishing value.
2. Protruding beyond the plane of the base architectural elements, areas where wooden surfaces meet stone, brick and concrete structures must be plastered using the reinforcing mesh fixed on them. Entirely wooden bases must be finished over shingled panels.
3. Brick, concrete and stone walls constructed using the freezing method must be plastered only after they have been thawed from the inside, no less than half their thickness.
4. When working on brick walls, if the air temperature is +24° or more, their surface should be moistened before plastering.
5. When covering the surface with single-layer plaster, it must be smoothed immediately after application. When using trowel units - after the mixture has set.
6. When laying a multi-layer coating, apply each layer only after preliminary hardening of the previous one. The soil must be leveled before it begins to set.

Conclusion

High-quality plaster according to SNiP guarantees that during subsequent installation finishing and there will be no problems in its operation. Having studied regulations, you will be able to carry out the finishing yourself or effectively supervise the work of hired plasterers. By watching the video in this article you will gain even more useful knowledge.

Plastering work is one of the main stages of repair, and the comfort in the house directly depends on it. Therefore, it is necessary to check not only the final result, but also the sequential execution of the technological process.

Before plastering work, it is necessary to thoroughly clean the room and prepare the surfaces. The walls should be free of dust, dirt and stains of various origins. In addition, it is necessary to maintain the temperature regime and control the humidity of the room.

The application of the solution should be uniform, and the layer thickness should be up to 50 mm.

Acceptance of works

Acceptance of completed work must begin with an inspection of the corners. This is the most prominent indicator by which you can easily assess the quality of plastering work. The resulting surfaces should be perfectly flat and smooth, with clear edges. All cracks, bumps, potholes and gaps are the main sign of poorly performed plastering work.

To check the strength of the connection between the plaster and the surface, you need to apply several blows with your palm to the sides of the corners and in random places. No peeling or booming sounds from voids are allowed.

Besides visual inspection you need to take a rule-rule, 2.5 meters in size, and apply it to the plastered surface. If for such a length the gap to the surface does not exceed 5 mm, then the result is excellent. To check the verticality of the walls, a level or plumb line is required. The quality criterion is the same - the gap is no more than 5 mm per 2.5 meters of length.

The thickness of the plaster must meet the following data:

• Simple up to 12 mm.
• Improved to 15 mm.
• High quality up to 20 mm.

Quality requirements for various types of plaster.

On smooth brick surfaces, the thickness of the plaster can be up to 10 mm, and on new concrete surfaces up to 2 - 3 mm, i.e. cover with grout. On surfaces made of straw, reed and fiberboard, the thickness of the plaster should not exceed 20 mm without additional preparation. On wooden surfaces It is advisable to install a layer of plaster 20 mm thick or at least 15 mm from the level of the exit shingles, since thinner layers of mortar are easily torn due to warping of filled shingles, and the shingles themselves are “imprinted” on the surface of the plaster.

The plaster must adhere firmly to the surface and not peel off; have a well-trodden surface, without external defects. The accuracy of the plastering is checked using a rule (slat) 2 m long. To do this, the rule is applied to the surface of the plastered wall in different directions: vertically, horizontally, diagonally. If the deviations are greater than the norms given in table. 1, they are eliminated (the solution is cut off or additionally applied).

The verticality and horizontality of simple plaster is controlled by a rule or a cord, that is, by pulling the cord with an indentation to the thickness of the plaster and placing stamps and beacons under this cord. For improved and high-quality plaster, surfaces are hung, marks and beacons are arranged.

Plaster quality

Plaster quality indicators

Indicators	Permissible deviations on the quality of the plaster.
	Simple.	Improved.	High quality and decorative.
Surface irregularities are detected by applying a 2 meter long rule.	No more than three irregularities with a depth or height of up to 5 mm.	No more than two irregularities with a depth or height of up to 3 mm.	No more than two irregularities with a depth or height of up to 2 mm.
Deviations of the surface from the vertical.	15 mm. to the entire height of the room.	2 mm. per 1 meter of height, but not more than 10 mm. to the entire height of the room.	1 mm. per 1 meter of height, but not more than 5 mm. to the entire height of the room.
Deviations of the surface from the horizontal.	15 mm. for the entire room.	2 mm. per 1 meter of length, but not more than 10 mm. for the entire length of the room or its part limited by purlins and beams.	1 mm. per 1 meter of length, but not more than 7 mm. for the entire length of the room or its part limited by purlins and beams.
Deviations of husks, studs, window and door slopes, pilasters, pillars from the vertical and horizontal.	10 mm for the entire element.	2 mm. per 1 meter of height or length, but not more than 5 mm. for the entire element.	1 mm. per 1 meter of height or length, but not more than 3 mm. for the entire element.
Deviations of the radius of curved surfaces from the design value (checked with a pattern) mm.	10 mm.	7 mm.	5 mm.
Deviations of the width of the plastered slope from the design, mm.	Not checked.	3 mm.	2 mm.
Deviations of rods from a straight line within the limits between the intersection angles and braces, mm.	6 mm.	3 mm.	2 mm.

Textbook Plastering works. Shepelev.A.M.