Ppr on the screed with cement-sand mortar. Technological map for the device of a semi-dry screed. Organization and technology of work
TYPICAL TECHNOLOGICAL CARD
Arrangement of cement-sand floor screed with fiber reinforcement in a mechanized way
1 AREA OF USE
1.1. The technological map is developed for the device of cement-sand screeds from a hard semi-dry mortar, with the addition of polypropylene synthetic fiber (building microreinforcing fiber - VSM), performed by a mechanized method, designed to level the surfaces of the underlying floor element or to give the floor a given slope.
The thickness, strength of the screed and the material are assigned by the project, depending on the type of floor covering, the structure of the floors and the purpose of the premises based on the requirements:
SP 29.13330.2011 Floors. Updated edition of SNiP 2.03.13-88;
Floors. The set of rules (in the development of SNiP 2.03.13-88 "Floors" and SNiP 3.04.01-87 "Insulation and finishing coatings");
MDS 31-6.2000 "Recommendations for the construction of floors", regulating the sequence of operations for the preparation and installation of cement-sand hard semi-dry mixtures (mortars) using polypropylene synthetic fiber, - screed device and quality control of the work performed (Fig. 1).
Fig. 1. Fiber screed device
When developing this technological map, the requirements for the quality of the materials used were also taken into account:
GOST 8736-93 Sand for construction work. Specifications (as amended);
GOST 25328-82 Cement for mortars. Technical conditions;
GOST 7473-2010 Concrete mixtures. Technical conditions;
Change N 1 GOST 28013-98 Building solutions. General technical conditions.
The developed technology for the manufacture and installation of screeds with the use of fiberglass, modern Russian and German equipment is used in a variety of industries:
Housing and civil complexes;
In industrial, civil and public buildings (Fig. 2);
Fig. 2. Floor screed device in industrial, civil and public buildings
In production and industrial workshops;
When arranging storage facilities;
In garages and car repair shops;
In trade halls and exhibition complexes;
In multi-storey car parks;
In aircraft hangars and cargo terminals;
In offices, basements and roofs.
Technological stages of the device of the floor screed by a mechanized method with fiber reinforcement (fig. 3)
The necessary measurements are taken, a topographic map of the room is drawn up. The goal is to measure the area and thickness of the layer. Deviations from the horizon line to the existing coverage are recorded from a given reference point (options are possible) using a laser level. Based on the fixation of deviations and their further miscalculation at many points, the future thickness of the screed is determined;
The base is being prepared - the surface is freed from foreign objects, debris;
In the immediate vicinity of the object of work (on the street), equipment is located - a pneumatic blower. It is a self-contained unit with a diesel engine in the form of a semi-trailer;
Mortar hoses, through which the mixture prepared in the pneumosupercharger is transmitted to the work site, are mounted from the equipment to the premises;
The necessary materials are placed in the immediate vicinity of the equipment - sand, cement, fiberglass, plasticizer, water (constantly replenished container);
The surface in the room is covered with a technical film, a damper tape is mounted around the perimeter of the room and at the points of abutment to vertical surfaces;
In certain proportions, the material is fed into the mixing chamber of the pneumosupercharger, mixed and fed in portions to the work site (the possibility of supplying the finished solution to a height of up to the 30th floor);
The mixture is taken using a special damper connected to the high-pressure hoses, it is planned in advance and rammed;
From a given horizon line, using a special technology, beacons are formed from the ready-made solution for laying in the future a ready-made hard (semi-dry) solution at an equal distance from a given horizon line;
With the help of special smoothing rails (rules), a surface is formed according to previously made beacons;
The surface is rubbed and additionally compacted with a surface grinder;
Expansion seams are cut;
The surface is covered with plastic wrap.
Fig. 3. Technological stages of the screed device
2. GENERAL PROVISIONS
ORGANIZATION OF THE CONSTRUCTION PROCESS FOR THE DEVICE OF THE FLOOR SCREEDING
2.1. A screed is a monolithic or prefabricated layer of relatively strong material in multi-layer structures of floors and roofs of buildings. Designed for the perception, distribution and transmission of loads (for example, on the roofs - snow cover, on the floors - the presence of people, goods, equipment), for leveling the underlying layer or giving the covering layer of roof and floor structures a given slope, as well as for flooring them with a finishing cover, movement of equipment and people on it.
2.2. Work on the installation of a screed with the use of fiber (construction microreinforcing fiber - VSM) must be carried out in accordance with the requirements of SNiP after the completion of construction and installation work, during the production of which the screed may be damaged.
2.3. The screed device can be carried out at an air temperature at floor level and a temperature of the underlying layer not lower than 5 ° C, the temperature must be maintained for the entire duration of the work and until the screed acquires a strength of at least 50% of the design.
2.4. A screed made of a hard semi-dry mortar, performed by a mechanized method, must be laid from one time to the design height.
2.5. In order to prevent the transfer of deformations to the floor screed from the building structures along the walls, around the columns and foundations, insulating joints are arranged by laying insulating material (damping tapes made of expanded polyethylene, isolon, isocom) to the entire height of the screed just before laying the mortar.
2.6. To prevent chaotic cracking of the screed during hardening and gaining strength, it is necessary to cut shrinkage seams, as a result of which the screed will crack in a given direction. Shrinkage joints should be cut along the column axes and butted with the corners of the joints along the perimeter of the columns. The floor map formed by the shrinkage joints is cut into squares if possible. The length of the card should not exceed 1.5 times its width. The generally accepted rule is that the smaller the card, the less chance of chaotic cracking.
2.7. When constructing screeds from a hard semi-dry mortar, taking into account their design features, the following should be performed at the facility:
Preparatory work:
Provision of access roads of freight transport to the place of work;
Determine the place of installation of equipment and storage of building materials for the manufacture and supply of mortar mixture;
Providing a power access point;
Providing the necessary lighting for the work site;
Ensuring the supply of service water to the installation site of the equipment.
Technological operations:
Cleaning the surface of the underlying layer;
Making marks of a clean floor;
Installation of insulating material for the entire height of the screed along the perimeter of the walls, around the columns and foundations;
Preparation of cement-sand mortar;
Supply of mortar to the place of installation;
Arrangement of beacons;
Laying cement-sand mortar;
Grinding the screed surface with trowels (Fig. 4);
Fig. 4. Screed Surface Grinding Machine
Cutting expansion joints.
Materials (edit)
The choice of work technology, the use of the necessary equipment, initial building materials forfloor screed devices
due to the purpose of the latter and the requirements that the practice of their operation puts forward to them.
For the production of semi-dry cement-sand screed, the following are used:
Fig. 5. Sand for construction works
Sand
for construction work (GOST 8736-93 Sand for construction work. Specifications (as amended)), used for the preparation of a solution when installing screeds, must have a particle size of no more than 3 mm and not contain clay particles more than 3% by weight (Fig. 5).
Fig. 6. Cement
Cement
- Portland cement not lower than PTs-400 DO grade. To bringcement marking
in accordance with the European standard EN 197-1, a new GOST 30515 has been introduced in the Russian Federation. It is used in the production of critical concrete and reinforced concrete structures in industrial construction, where high requirements are imposed on water resistance, frost resistance, durability (Fig. 6).
Fig. 7. Fiber polypropylene
Fiber polypropylene
is a building microreinforcing fiber (VSM), added to cement-sand mortars, inconcrete
, foam concrete, etc. (fig. 7). The main task of the fiber reinforcement of the above materials is to increase the strength indicators for impact strength, crack resistance, increase the tensile strength of the material, as a result of which the materials acquire qualitatively new properties. Building microreinforcing fiber - VSM (synthetic fiber, fiber) is a multifunctional reinforcing additive for concrete and mortars.
Constructive solutions for the construction of the base for floors in the formmonolithic floating screed
additionally include polyethylene film, insulation (damper tapes) and heat and sound insulation materials as constituent elements of the screed (Fig. 8-11).
Fig. 8. Sound insulation underlay
Fig. 9. Penoplex
Fig. 10. Polyethylene film
Fig. 11. Damper tape
Applied equipment and tools:
Pneumatic mortar pump with a hopper for the preparation of a semi-dry screed, manufactured by Brinkman, Putzmeister, Germany, electric smoothing (grinding) machines, a laser level, rules and other small tools (Fig. 12-14).
Fig. 12. Laser level
Fig. 13. Pneumatic mortar pump with a hopper for preparing a semi-dry screed
Fig. 14. Electric smoothing (sander) machine
3. ORGANIZATION AND TECHNOLOGY OF PERFORMANCE OF WORKS ON THE DEVICE OF THE FLOOR SCREEDING
3.1. The surface of the underlying layer is cleaned before laying the cement-sand mortar. The surface of the base is inspected, thoroughly cleaned of debris and extraneous layers, dust is removed using an industrial vacuum cleaner, the horizontalness of the base and the correctness of the slopes are checked, grease stains are removed, if there are cracks at the base, cracks are expanded and filled with a repair compound, the gaps between the prefabricated plates are closed. The substrate must be clean, sound and free of delamination.
3.2. Making marks. The level of the finished floor is carried out by surveyors using a laser level. It should be borne in mind that the level of the finished floor must be the same in all rooms of the apartment or part of the floor located between adjacent stairwells.
3.3. Insulation seams. In order to prevent the transfer of deformations to the floor screed from the building structures along the walls, around the columns and foundations, insulating seams are arranged by laying an insulating material (damping tapes made of expanded polyethylene, izolon, isocom) with a thickness of 4-8 mm to the entire height of the screed immediately before laying the mortar.
3.4. Screed preparation. The place for the installation of the compressor, pneumatic transport specialized equipment for the preparation and supply of the mixture, the place of storage of building materials must be indicated in the project for the production of works or agreed with the Customer. The required area for placing equipment and materials is from 30 to 50 m... Semi-dry screed is prepared directly at the construction site or at the work site.
When preparing a screed by a mechanized method with the use of fiberglass, certain requirements are observed, the ratio of the volume of sand to the volume of cement, which should be a ratio of 3: 1, under the strict condition that the washed seeded sand corresponds to a fraction of the size modulus of 2-3 mm. Standard pneumatic conveying equipment has a mixing hopper volume of 250 liters, the actual volume of the finished mixture is 200 liters. The minimum amount of cement per hopper load should not be less than 50 kg (1 standard bag). The water-cement ratio is in the range of 0.34-0.45, which corresponds to 17-24 liters of water per bunker load.
Loading of sand, cement and water is carried out in two stages. First stage: first loadedvolume of sand (about 75 kg) and a 50 kg bag of cement. Then 10-12 liters of water and polypropylene fiber are added. The second stage: the final loading of the working bunker with sand of about 100 kg and the required amount of water of about 7-12 liters, as well as fiber, is carried out. The consumption of the used polypropylene fiber is about 120-150 grams per full load of the hopper, i.e. for one batch at the rate of 700-900 grams per cubic meter of the prepared solution. Fibrin is added with every proportion of water. The full loaded mass is mixed for at least two minutes. The total running time of the mixing hopper, taking into account the loading time, is from 4 to 7 minutes.
3.5. Supply of mortar to the place of installation. The prepared cement-sand mortar under pressure is fed in portions through rubber hoses directly to the place of installation and is placed on the base through the mortar absorber. On large areas, the floor screed is carried out with cards. The size of the map is determined by the productivity of the working unit, i.e. floor area laid in one working shift. The time for feeding the prepared solution should not exceed 5 minutes. Depending on the type of equipment, the feed can be carried out at a distance of up to 160 meters horizontally and 100 meters in height. If it is necessary to deliver the solution to a distance of more than 100 meters, the delivery time can take up to 7-15 minutes. At a negative outside air temperature not exceeding minus 10 ° C, the preparation and supply of the solution is possible with the obligatory arrangement of the so-called "greenhouse" at the installation site of the compressor, pneumatic transport specialized equipment.
3.6. Installation of beacons and laying of cement-sand mortar. The device of beacons is made from a freshly prepared solution with a preliminary leveling with a level without installing guides (Fig. 15).
Fig. 15. Installation of beacons and laying of cement-sand mortar
After the cement-sand semi-dry mixture (mortar) is supplied to the place of work, the entire volume of the prepared map is filled with the mixture. The mixture is stretched with a screed rule, moved with a double-sided support on these beacons until a flat surface is obtained. In the process of work, it is necessary to monitor the state of the exposed beacons. Leveling of the surface and installation of beacons is carried out simultaneously, thereby achieving uniformity of laying and in the future a complete absence of cracks.
3.7. Grinding the screed surface (fig. 16). Work on grinding the surface should be started immediately after leveling the mortar and finished before the mortar begins to set within 1.5-2 hours from the moment of filing. The surface should be sanded with a trowel equipped with a leveling disc and in special shoes - concrete shoes.
Fig. 16. Grinding the screed surface
3.8. Cutting expansion joints (Fig. 17). To prevent chaotic cracking of the screed during hardening and gaining strength, it is necessary to cut expansion joints, as a result of which the screed cracks in a given direction. There are three main types of expansion joints:
Insulation seams;
Shrinkage seams;
Structural seams.
It is more expedient to cut the shrinkage joints in a freshly laid mortar with a special cutter after the surface of the mortar has been treated with a trowel. The seams must be cut along the axes of the columns and docked with the corners of the seams along the perimeter of the columns. The floor map formed by the shrinkage joints is cut into squares if possible. The length of the card must not exceed 1.5 times its width. The seam depth should be 1/3 of the screed thickness. The seams allow you to create straight planes of slack in the screed. Obviously, the smaller the map, the less chance of chaotic cracking.
Fig. 17. Cutting expansion joints
Structural seams are tripled in places where the work of laying the screed of the working link ends in a shift. Structural joints work on the shrinkage principle and, if possible, should be aligned.
4. REQUIREMENTS FOR THE QUALITY OF WORKS
4.1. Acceptance of work on the installation of screeds is carried out in accordance with the requirements of SP 29.13330.2011 Floors. Updated edition of SNiP 2.03.13-88 (section 8 Screed (base for floor covering)).
4.2. The smallest thickness of a cement-sand or concrete screed to create a slope at the junction with gutters, channels and ladders should be: when laying it on floor slabs - 20 mm, on a heat and sound insulating layer - 40 mm. The thickness of the screed for covering pipelines (including in heated floors) must be at least 45 mm greater than the diameter of the pipelines.
4.3. To level the surface of the underlying layer and cover the pipelines, as well as to create a slope on the floor, monolithic screeds made of concrete of a class of at least B12.5 or from cement-sand mortars based on dry building floor mixtures on a cement binder with a compressive strength of at least 15 MPa.
4.4. The thickness of monolithic screeds made of dispersion-self-compacting mortars based on dry mixes of building flooring with a cement binder, used to level the surface of the underlying layer, should be at least 1.5 times the diameter of the maximum filler contained in the composition.
4.5. The bond strength (adhesion) of screeds based on a cement binder for pulling off with a concrete base at the age of 28 days should be at least 0.6 MPa. The adhesion strength of the hardened mortar (concrete) to the concrete base after 7 days should be at least 50% of the design.
4.6. At the junctions of screeds made of sound-insulating gaskets or backfills with other structures (walls, partitions, pipelines passing through ceilings, etc.), gaps of 25-30 mm wide must be provided for the entire thickness of the screed, filled with sound-insulating material.
4.7. In rooms, during the operation of which air temperature drops (positive and negative) are possible, expansion joints must be provided in the cement-sand or concrete screed, which must coincide with the axes of the columns, seams of floor slabs, expansion joints in the underlying layer. Expansion joints should be sewn with a polymer elastic composition.
4.8. In screeds of heated floors, it is necessary to provide for expansion joints, cut in the longitudinal and transverse directions. The seams are cut through the entire thickness of the screed and are sewn with a polymer elastic composition. The step of expansion joints should be no more than 6 m.
5. NEED FOR MATERIAL AND TECHNICAL RESOURCES
5.1. Sand for construction work. GOST 8736-93 Sand for construction work. Specifications (as amended).
5.2. GOST 25328-82 Cement for mortars. "Specifications".
5.3. GOST 7473-2010 Concrete mixtures. Technical conditions.
5.4. Change N 1 GOST 28013-98 Building solutions. General technical conditions.
5.5. The need for tools, equipment and fixtures is shown in Table 1.
Table 1
Necessary equipment and tools
Np / p
Equipment for preparation and supply of solutions
Unit rev., pcs.
Quantity
Mortar pump (pneumatic blower)
PCS.
Floor screed trowel
PCS.
Seam cutting machine (seam cutter)
PCS.
Industrial vacuum cleaner
PCS.
Rail-rule length 3 m
PCS.
Control rail
PCS.
Construction level
PCS.
Laser level
PCS.
Base scraper
PCS.
LP type shovel
PCS.
Tank for technical water
PCS.
Bucket
PCS.
6. SAFETY AND LABOR PROTECTION
6.1. Before starting work on the installation of screeds, the person responsible for the production is obliged to ensure that the workers are briefed and the necessary overalls and personal protective equipment are issued. When performing work, it is necessary to comply with the safety rules set out in SNiP 12-03-2001 Labor safety in construction. Part 1. General requirements and SNiP 12-04-2002 Labor safety in construction. Part 2. Construction production.
6.2. Pay particular attention to the following:
Persons at least 18 years of age who have passed a medical examination, have a certain qualification, know the device and design features of the equipment, have a certificate for the right to service them, are allowed to service installations and mechanisms;
According to the "Rules for the technical operation of electrical installations of consumers", the installations must have their own grounding center.
6.3. Before starting work, the driver must:
Carry out an external inspection of the installation;
Check the serviceability of electrical wiring and grounding;
Check the alarm system to the workplaces.
6.4. During work, the driver must:
Start and stop the solution supply only on a signal from the workplace;
Serve the solution only after thorough mixing.
6.5. Persons who have undergone special training and have a certificate for the right to operate are allowed to operate and maintain the equipment. Pressure gauges and safety valves must be sealed. The maintenance of the trowel must be entrusted to a worker who is familiar with the operating instructions. The electrical connection of the machine must be done by an electrician.
7. TECHNICAL AND ECONOMIC INDICATORS
FER 81-02-11-2001 State estimate standards. Federal unit rates for construction and special construction work. Part 11. Floors (as amended by orders of the Ministry of Construction of Russia dated January 30, 2014 N 31 / pr, dated October 17, 2014 N 634 / pr, dated November 12, 2014 N 703 / pr).
BIBLIOGRAPHY
SP 29.13330.2011 Floors. Updated edition of SNiP 2.03.13-88.
Floors. The set of rules (in the development of SNiP 2.03.13-88 "Floors" and SNiP 3.04.01-87 "Insulation and finishing coatings").
GOST 8736-93 Sand for construction work. Specifications (as amended).
GOST 25328-82 Cement for mortars. Technical conditions.
GOST 7473-2010 Concrete mixtures. Technical conditions.
Change N 1 GOST 28013-98 Building solutions. General technical conditions.
SNiP 12-03-2001 Labor safety in construction. Part 1. General requirements.
SNiP 12-04-2002 Labor safety in construction. Part 2. Construction production.
SP 48.13330.2011 Organization of construction. Updated edition of SNiP 12-01-2004.
SP 50.13330.2012 Thermal protection of buildings. Updated edition of SNiP 23-02-2003.
GOST 12.1.044-89 SSBT. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination.
GOST 12.2.003-91 SSBT. Manufacturing equipment. General safety requirements.
GOST R 12.1.019-2009 SSBT. Electrical safety. General requirements and nomenclature of types of protection.
GOST 12.1.003-83 SSBT. Noise. General safety requirements.
GOST 12.1.004-91 SSBT. Fire safety. General requirements.
GOST 12.1.005-88 SSBT. General sanitary and hygienic requirements for the air in the working area.
GOST 12.4.011-89 SSBT. Protective equipment for workers. General requirements and classification.
GOST 12.2.013.0-91 SSBT. Hand-held electric machines. General safety requirements and test methods.
Resolution of the Government of the Russian Federation of April 25, 2012 N 390 On fire safety.
ST SRO OSMO-2-001-2010 Self-regulation standard. Electrical safety. General requirements at production facilities of organizations performing work that affect the safety of capital construction facilities.
This article describes the stages of a semi-dry floor screed device in a mechanized way using specialized equipment that is designed to mix the mortar and supply it to the construction site. The technological map for the device of a semi-dry screed includes several stages: preparation of the base, mixing the mortar, screed device and maintenance.
Screed thickness marking
The first thing that is done when installing a semi-dry screed is to measure the thickness of the future screed, for this a laser or water level is used. With the help of a level, the height of the screed and the future clean floor is applied to the wall. This distance is calculated based on the volume of the screed and the materials used.
The level of the screed is noted for several reasons, one of which is the maximum possible floor height, that is, the height that some elements in the room allow, for example, door sills. In addition, its weight depends on the thickness of the screed, and for some rooms this is important, since the load-bearing structures of buildings have a load limit. The semi-dry screed is the heaviest of all, the weight of a centimeter screed is 18-20 kilograms per square meter. For example, light types of screeds weigh 14-18 kilograms per square meter, and centimeter-level self-leveling floors weigh 12-16 kilograms per square meter.
Preparation of the base
Screed problems arise, as a rule, due to a poorly prepared base. After the cement-sand mixture begins to dry out, the entire floor screed, in the process of moisture evaporation, begins to decrease in volume and shrink, but at the same time it firmly adheres to the walls. This should happen with the base of the floor, but, in some cases, the screed begins to come off the floor and because of this, voids are formed between them. In addition, the screed can pull on itself and the fragile top layer of the base, leading to the same consequences. To avoid the appearance of voids between the ceiling and the cement-sand screed, it is necessary to prepare the base of the floor with high quality.
The preparation of the base for a semi-dry screed begins with the removal of debris and the removal of all fittings sticking out of the ceiling, the rods of which are bent with a heavy hammer (it is not at all necessary to cut them at the root, the screed will hide everything). All areas lagging behind the overlap are removed using a punch. To make the semi-dry screed more firmly adhered to the base of the floor, the overlap is processed with a grinder. If you decide to make a semi-dry screed on your own, and you do not have special equipment, then on the base of the floor you can hollow out notches with an ax, which will remove all the elements lagging behind the overlap and help the solution to fix better. But, the device of a semi-dry screed is an important part of construction and repair work, therefore, to create it, it is better to contact a specialized company such as Express screed. During the installation work, our company uses only the latest equipment from Germany, which allows us to carry out all the work with high quality and in just one day.
After the entire surface of the floor has been tapped with a hammer, processed with a grinder and the lagging parts have been removed, all large recesses are closed. For this, the same cement-sand mortar is used, which is involved in the screed device, sometimes inexpensive tile adhesive is used. If there is a need to create a waterproofing floor, then it is better to use tile adhesive, since it has a waterproof property. But, before all the potholes on the floor are repaired, they are treated with a primer or cement laitance, if the filling is done with a cement-sand mortar. If the holes will be filled with tile adhesive, then a special glue primer is used for processing.
If there are differences in height on the basis of the floor, they are not leveled out, this is a waste of time and effort, and the screed will hide all the shortcomings. As for the potholes and pits, they are sealed quickly and without much effort, the main thing is that during the laying of the screed, the solution does not fall into them. The gaps between the floor slabs and the walls are closed, even if they are not visible. These places are still rubbed with mortar, since the targets can simply not be noticed, and the water from the screed seeps into a small crack. After all work, the base is cleaned of debris and dust.
Base primer
The screed primer is used with the mark “for concrete substrates” or “for absorbent surfaces”. For the device of a cement-sand screed, factory primers from any manufacturer are used. The primer is applied to concrete floors with brushes; a roller, as a rule, is not used, as it can skip irregularities. When using those primers that allow drying, apply two layers, if the manufacturer recommends applying the screed only on a wet primer, then it is applied immediately before the screed device.
Installation of beacons
The next stage in the device of a semi-dry screed is the installation of beacons. This part of the whole process can be safely called the most painstaking and, at the same time, the most responsible, the evenness of the entire screed will subsequently depend on the installation of beacons. For the device of a semi-dry screed, an aluminum rule is used, since the quality of the material and equipment is a significant part of the success of the entire event. The company "Expressstyazhka" uses only modern equipment and high-quality materials that allow you to make a perfectly flat floor without cracks and unevenness.
For the device of a semi-dry screed, as a rule, several rules are used, a long two-meter and a short meter, especially if the work is done in an apartment. A long rule for large rooms, and a short rule for corridors and other small rooms. If one rule is used, then its length is usually the same as the width of the room. For the device of a semi-dry screed, a wooden rule is no longer used, since it does not provide the same quality as an aluminum one.
Semi-dry screed beacons are mounted in one of three ways:
- Shtyrev.
- Mortar.
- On metal guides.
Installing the damper connection
A damper connection is installed around the perimeter of the room. Its installation begins with laying a waterproofing layer, in such a way that one side of the canvas goes to the walls just above the level of the future screed, and the other remains on the base of the floor. For these purposes, a two-millimeter plastic film, roofing felt, waterproofing or other waterproofing material is used, it is cut into strips 30-40 centimeters wide. The damper connection is like a trough under a cement-sand mortar. A tape of waterproofing material is attached to the wall with liquid nails every 20-50 centimeters so that it does not come off.
On this "trough" a roll of insulation is glued, cut into strips, 8-15 centimeters wide, which is the damper connection of the screed and walls. A strip of insulation protects the screed from sticking to the wall, so it will not tear during the drying process. The damper connection protects the screed from temperature-damp expansion during operation.
Mixing the solution
To prepare a mortar of a semi-dry screed, the ratio of cement and sand is 3 to 1. For Turbosol M-250 equipment, a maximum of 250 kilograms and a minimum of 50 kilograms of mortar are mixed at a time (one standard bag of ready-made dry mix). A different ratio of cement to water (0.34-0.45) is added to each load, approximately 17-24 liters of water at a time.
All components of the solution (cement, water and sand) are mixed in the bunker of the machine in two steps:
- About 75 kilograms of sand + a bag of cement (kilogram) + a ten-liter bucket of water are loaded.
- Sand up to 100 kilograms is loaded into the working bunker and + 7-12 liters of water is added. The solution continues to mix for another 4-7 minutes.
Polypropylene fiber is added to the hopper at the rate of 700 grams per cubic meter of the finished solution. For a full load of the hopper, 120-150 grams of polypropylene fiber is added, the same amount is added for mixing a different volume. Fiber must be added in portions, for each bucket of water there is about 60-70 grams of material.
Semi-dry screed technology
The ready-made mortar for the semi-dry screed is delivered to the construction site using the pneumatic transport unit of the Turbosol M-250 equipment. In this case, the filing process should not exceed five minutes. In exceptional cases, when the height of the screed device exceeds 80 meters, and the length of the solution supply hose exceeds 150 meters, the time for transporting the mixture increases to 7-10 minutes.
If the air temperature is below zero at the location of the equipment for preparing and supplying the solution, then a "hot house" is necessarily installed. At the same time, the equipment "Turbosol M-250", even after the installation of the "greenhouse", is intended for use only up to a mark of at least -10 degrees. If the temperature is below this threshold, screed work is usually postponed to a more appropriate time.
A semi-dry screed is laid only in a room with a positive air temperature and a temperature of the materials used not lower than +5 degrees. In the cold season, the room temperature is measured near windows and doors at a height of half a meter from the base.
The semi-dry screed should not come into contact with the enclosing structures in the room (walls, columns, etc.); for this, damper (soundproof) tapes are laid.
The device of a semi-dry screed is made immediately of the required thickness, since it serves as the basis for a clean floor.
The minimum thickness of a semi-dry screed must be at least 40 millimeters, in exceptional cases, the local minimum thickness may be 30 millimeters. The maximum thickness is limited only by the bearing capacity of the room, but creating a screed thicker than 60-70 millimeters is impractical, it is too heavy. If it is necessary to make a screed of this thickness, the semi-dry screed is replaced with lighter options.
After the prepared cement-sand mortar is delivered to the place of the semi-dry screed device, it is evenly distributed on the floor surface between the beacons and leveled with an aluminum rule that rests on these beacons on both sides.
Grinding of the laid screed is carried out immediately after the end of work, but no more than an hour after the filing of the solution. The grinding process is carried out by a sander with a leveling disc.
For large rooms (more than 45 square meters), a work performance map is prepared, which includes the sequence of pouring the solution into areas of 10-15 square meters. After the first section is leveled, workers simultaneously proceed to grout it and level the second section. In this case, the processing of individual sections of the room is not carried out, and a 2-3 mm gap at the point of their abutment forms an expansion joint.
Expansion joints of the slab are used for those rooms in which the size of one section exceeds 6 meters. The expansion joints of the slab are made in one of two ways:
In the process of grinding the screed, expansion joints are made with a width of 5-7 millimeters. They are made in the following way: the places where adjacent areas adjoin to each other are cleaned from the crumbling remains of the mixture with a trowel. After that, these joints are rubbed with a small amount of cement-sand mortar. This achieves the appearance of a perfectly flat and uniform surface.
Screed care
The finished screed is covered with plastic wrap, which ensures the normal reaction of cement and water. Over the next day, beacons and self-tapping screws are removed from the screed, the holes that appear are sealed and overwritten. The screed is sprayed from the spray bottle and covered with foil again. For the next three days, the screed is checked for cracks and, if necessary, sprayed with water again.
When carrying out high-quality work on the device of a semi-dry screed, there should not be any gaps in the solution and such a floor is suitable for laying any floor covering. The screed gains half of its strength in nine days, after 28 days from the date of installation it gains 90% strength and this indicator is branded strength, the remaining 10% of the semi-dry screed gains over the years.
The semi-dry screed is an excellent base for laying any floor covering. But, the main thing is that it should be fulfilled according to all technological requirements, only in this case we can talk about its durability. The Express screed company gives a three-year guarantee for its work, and in the process of installing a semi-dry screed, it uses only modern equipment and high-quality materials. The quality of your screed depends on the choice of the company, so trust only professionals.
High-quality and fast installation of a semi-dry floor screed
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3.1. Surface cleaning the base is carried out before laying the separation layer. The surface of the base is inspected, thoroughly cleaned of debris and extraneous layers, the horizontality of the base and the correctness of the slopes are checked, if there are cracks in the base, the cracks are expanded and filled with a repair compound, the gaps between the prefabricated plates are closed. The substrate must be clean, sound and free of delamination.
3.2. Making marks... The level of the finished floor is carried out by surveyors using a laser level. It should be borne in mind that the level of the finished floor must be the same in all rooms of the apartment or part of the floor located between adjacent stairwells.
3.3. Insulation seams... In order to prevent the transfer of deformations to the floor screed from the building structures along the walls, around the columns and foundations, insulating joints are arranged by laying an insulating material (damping tapes made of expanded polyethylene, isolon, isocom) with a thickness of 4-8 mm. to the entire height of the screed just before laying the mortar.
3.4. Equipment installation... The place for the installation of the compressor, pneumatic transport specialized equipment for the preparation and supply of the mixture, the place of storage of building materials must be indicated in the project for the production of works or agreed with the Customer. The required area for placing equipment and materials is from 30 to 50 m2; Semi-dry screed is prepared directly at the construction site or at the work site.
When preparing a mortar for a screed by a mechanized method using fiber-optic fiber, certain requirements are observed, the ratio of the volume of sand to the volume of cement, which should be 3: 1, under the strict condition that the washed seeded sand corresponds to a fraction with a size modulus of 2-3 mm. Standard pneumatic conveying equipment has a mixing hopper volume of 250 liters, the actual volume of the finished mixture is 200 liters. The minimum amount of cement per hopper load should not be less than 50 kg (1 standard bag). The water-cement ratio is in the range of 0.34 - 0.45, which corresponds to 17-24 liters of water per bunker load.
Loading of sand, cement and water is carried out in two stages... First stage: - First, ½ the volume of sand (about 75 kg) and a 50 kg bag of cement are loaded. Then 10-12 liters of water and polypropylene fiber are added. The second stage: - the final loading of the working bunker with sand of about 100 kg and the required amount of water of about 7-12 liters, as well as fiber is carried out. The consumption of the used polypropylene fiber is about 120 - 150 grams per full load of the bunker, i.e. for one batch at the rate of 700-900 grams per cubic meter of the prepared solution. Fibrin is added with every proportion of water. The full loaded mass is mixed for at least two minutes. The total running time of the mixing hopper, taking into account the loading time, is from 4 to 7 minutes.
3.5. Supply of mortar to the place of installation... The prepared cement-sand mortar under pressure, in portions through rubber hoses, lends itself directly to the installation site and through the mortar absorber is laid on the base. On large areas, the floor screed is carried out with cards. The size of the map is determined by the productivity of the working unit, that is, the area of the floor laid in one working shift. The time for feeding the prepared solution should not exceed 5 minutes. Depending on the type of equipment, the feed can be carried out at a distance of up to 160 meters horizontally and 100 meters in height. If it is necessary to deliver the solution to a distance of more than 100 meters, the delivery time can take up to 7-15 minutes. At negative outside air temperatures not exceeding minus 10 0С, preparation and supply of the solution is possible with the obligatory arrangement of the so-called "teplag" at the installation site of the compressor, pneumatic transport specialized equipment.
3.6. Installation of beacons and laying of cement-sand mortar... The device of beacons is made from a freshly prepared solution with a preliminary leveling with a level without installing guides. After the cement - sand semidry mixture (mortar) is supplied to the place of work, the entire volume of the prepared card is filled with the mixture. The mixture is stretched with a screed rule, moved with a double-sided support on these beacons until a flat surface is obtained. In the process of work, it is necessary to monitor the state of the exposed beacons. Leveling of the surface and installation of beacons is carried out simultaneously, thereby achieving uniformity of laying and in the future a complete absence of cracks.
3.7. Grinding the screed surface... Work on grinding the surface should be started immediately after leveling the mortar and finished before the mortar starts to set within 1.5 - 2 hours from the moment of filing. The surface should be sanded with a trowel equipped with a leveling disc and in special shoes - concrete steps.
3.8. Cutting expansion joints... To prevent chaotic cracking of the screed during hardening and gaining strength, it is necessary to cut expansion joints, as a result of which the screed cracks in a given direction.
There are three main types of expansion joints:- - Insulation seams
- - Shrinkage seams
- - Construction joints
Shrinkage seams it is more expedient to cut in a freshly laid solution with a special cutter after processing the surface of the solution with a trowel. The seams must be cut along the axes of the columns and docked with the corners of the seams along the perimeter of the columns. The floor map formed by the shrinkage joints is cut into squares if possible. The length of the card should not exceed 1.5 times its width. The seam depth should be 1/3 of the screed thickness. The seams allow you to create straight planes of slack in the screed. Obviously, the smaller the map, the less chance of chaotic cracking.
Structural seams are tripled in places where the work of laying the screed of the working link ends in a shift. Structural seams work according to the shrinkage principle and, if possible, should be aligned.
Example Example of a WPS for a soundproofed floor screed.
TECHNOLOGICAL CARD FOR FLOOR SCREWING DEVICE
In the residential complex "12 Kvartall", Khimki
The terms of reference provide for the installation of a floating cement-sand floor screed with impact sound insulation in the apartments.
We suggest using the PENOLON sheet soundproofing material 8 mm thick as impact sound insulation. In combination with a floating cement-sand screed with a thickness of 60-70 mm, as well as when using a damper tape made of foamed polyethylene with a thickness of 5 mm, the screed design provides an index of improvement of shock and acoustic insulation within the normative SNiP 23-03-2003 "Noise protection »In residential and public buildings.
Before installing the floor screed, the following work must be done:
a) Floor wiring for electrical and internet cables. It is advisable to lay in a corrugated pipe.
b) Waterproofing of toilets and bathrooms (it is allowed to perform a coating waterproofing 2 weeks after screed on the screed surface).
c) Plumbing in bathrooms (washbasins, washing machines, showers).
Stages of work on the installation of floor screed in the apartment:
1. Debris is removed from the surface of the concrete base, large build-ups of concrete are cut down.
2. On the surface of the floor slab, roll-up sound insulation "PENOLON" with a thickness of 8 mm is spread. The joint of the soundproofing sheets is glued with tape.
3. A damper tape is installed along the perimeter of the premises to the depth of the screed - foamed polyethylene, 5 mm thick.
4. On the street, at the entrance, equipment is installed for the preparation and supply of solution (pneumatic blower), a water tank of 200 liters. Cement and sand are temporarily stored in the required volume.
5. A rubber sleeve ( d 65mm) through which the cement-sand mixture for the floor screed will flow.
6. Production of screed from cement-sand mortar:
· The preparation of the solution for the screed device is carried out directly at the entrance. The mixture is prepared according to the following algorithm: the brought washed quarry or river sand (particle size modulus = 2.2-3 mm) is poured into the mixing tank of the pneumatic blower. 1 bag of cement (50 kg), water and fiberglass are poured there. Mixing occurs. With the correct loading of the tank, the mixing process ends with the addition of the last components, the mixture becomes homogeneous. The tank is filled as follows: 1) Sand 50 liters; 2) Cement brand CEM II - 32.5 D20 - 50 kg; 3) water 10 liters (with natural sand moisture); 4).; 5) sand 64 liters. 6) water 8-12 liters. The volume of the tank allows preparing 200 liters of cement-sand mixture of optimal quality and proportions in one full load.
· The transportation of the finished mixture of cement-sand mortar is carried out by compressed air through flexible hoses. The prepared solution with a volume of 0.2 m³ is automatically divided into small portions and, under pressure, flows through hoses directly to the work site (apartment) to the damper. In the damper, the working pressure is discharged, after which the solution is poured onto the surface of the concrete floor for laying.
· The solution received from the extinguisher is manually distributed in an even layer throughout the room. A mixture of semi-dry cement-sand mortar is laid, compacted and leveled with a hand tool (rule). The level is controlled by a laser level. Reduction of the volume of the mortar mixture due to compaction from 15 to 30 percent, depending on the size and voidness of the sand.
· After laying and leveling the mixture of cement-sand mortar, the surface of the screed is sanded with a disc trowel.
· At the end of grinding with a trowel or a spatula, expansion joints are cut with a depth of 1.5-2 cm (linear expansion), 2-4 mm wide. The seams are cut in accordance with the terms of reference, in its absence, in accordance with SNiP.
7. The remains of the cement-sand mixture, trimming of the damper tape and foam rubber are removed. The elevator hall, the corridor by the front door is swept.
8. The Certificate of Completion is signed.
Walking on the screed is possible after 12 hours, at an air temperature of +20 o С
Further finishing works are possible in 48 hours
2 days after the screed is installed, it is recommended to slightly moisten the screed surface with water by spraying (0.2-0.3 l per 1 m2). If the screed in the next 2-3 days is covered with PET film or other covering material (recommended for subsequent finishing work) by the Customer, moistening is not required.
