Do-it-yourself monolithic concrete floor. Prefabricated and monolithic reinforced concrete floors Monolithic reinforced concrete floor canopy constructive
Planning construction country cottage, the owner has to solve the difficult issue of choosing floors. Some contractors advise him to use reinforced concrete panels, others insist on using wooden beams as a floor.
We decided to help newbies get out of a difficult situation. In our article you will find an overview of the advantages and disadvantages of wooden interfloor floors.
Useful tips for installing them and important nuances doing this work will also not be superfluous. We hope that the information received will be useful to you at the construction site and will help you avoid serious mistakes.
There is a stereotype in the minds of citizens according to which prefabricated reinforced concrete panels are the only Possible Solution for any building. It is not difficult to overcome it.
It is enough to list the advantages of wooden beam floors:
- Minimum cost (1 m3 of timber is several times cheaper than 1 m3 of hollow-core panels);
- The load on the walls is 2-3 times less than from the panels. This allows you to significantly reduce the consumption of reinforcement and concrete when constructing the foundation;
- On short spans (up to 4 meters), wooden beams can be laid manually using simple devices (a winch or a lifting block). Installing heavy slabs without a powerful crane is an unrealistic task;
- Low labor intensity and high speed of work (compared to pouring a monolithic reinforced concrete floor);
- Environmental friendliness (concrete uses granite gravel, the background radiation of which can significantly exceed the norm).
As you know, there are no advantages without disadvantages. Wood floors have few of them:
- Increased deformability. It manifests itself in the effect of vibration when walking and the formation of cracks at the junction of plasterboard partitions;
- Low fire resistance (without special impregnation);
- Relatively short length (does not exceed 6 meters). For reinforced concrete panels it reaches 7.2 meters.
Among the disadvantages of these structures, some authors of feature articles include the formation of cracks in the ceiling plaster and poor insulation of impact noise. However, with a competent approach to installation, these two problems can be solved simply and reliably. To do this, a series of less thick beams are laid below the load-bearing beams, specially designed for lining the ceiling (plasterboard, OSB, lining, board).
The backing beam, like the main one, is placed on the wall, but lower, and the ceiling lining is attached to it. This solution is not found often, although it is competent and its history goes back more than one century; in addition to cutting off structural noise from the second floor, this option eliminates cracks in the ceiling. They appear when a beam serves as a support for the floor of the second floor and at the same time the ceiling of the first floor is attached to it. Vibration and shock loads cause cracks in the finish.
Areas of application and calculation of wooden floors
- in buildings constructed of wood (frame and log);
- in country houses designed for summer use;
- V outbuildings(barns, bathhouses, workshops);
- in prefabricated prefabricated houses.
In addition to the listed options, wooden structures for interfloor ceilings can be used in cottages intended for year-round residence. Only in this case you need to use the two-row beam installation system, which we described above.
We do not recommend selecting the section of timber according to the principle “the thicker the better”. Eat simple technique calculations taken from building regulations.
According to it, the height of the wooden beam must be at least 1/25 of the size of the span being covered. For example, with a 4-meter distance between the walls, you need to buy a saw log with a section height (H) of no less than 400/25 = 16 cm with a thickness (S) of 12 cm. To create a safety margin, the found parameters can be increased by 2-3 cm .
The second parameter that needs to be selected correctly is the number of beams. It depends on their pitch (the distance between the central axes). Knowing the section of the beam and the size of the span, the step is determined from the table.
Table. Choosing beam spacing
The design load of 350-400 kg/m2 indicated in the table is the maximum for the second floor. If it is not residential, then its value will not exceed 250 kg/m2.
When planning the layout of the beams, you need to take into account that the two outer ones must deviate from the end walls by at least 5 cm. The remaining beams are distributed evenly across the walls (in accordance with the selected pitch).
Installation stages and features
Technologically, the installation of floors using wooden beams cannot be called complex. The main attention should be paid to the horizontal alignment of the beams and the quality of embedding their ends into the wall mass. You cannot simply lay the beams on the masonry and cover them with bricks. It is necessary to provide them with a reliable connection with the walls and to properly protect the wood from rotting.
Options for sealing beams depending on masonry material, type wall structures(external, internal, chimney) and methods of their fastening are shown in the figures.
The length of the supporting part of the beams in a brick and block wall should be at least 16 cm (in a wooden wall 7-8 cm). If instead of timber, paired boards placed on edge are used, then they are embedded in the masonry at least 10 cm deep.
The side parts of the beams in contact with the wall are wrapped with 2 layers of glassine or 1 layer of roofing material. Experienced craftsmen cut the ends of the beams at an angle (60-70°) and leave them uninsulated, not forgetting to treat them with an antiseptic compound even with the rest of the part. This ensures the “breathing” of wood wrapped in waterproofing.
When installing the ceiling, small gaps (3-5 cm) are left on the sides of each beam, filled with mineral wool or tow. A heat insulator is also placed in the space between the end of each beam and the wall. This eliminates the “cold bridge” that occurs by reducing the thickness of the masonry.
When installing floors in walls made of aerated concrete and arbolite blocks, it is recommended to use an open seal. In this case, the ends of the beams are also cut at an angle, antiseptic and covered with roofing felt and mastic, leaving the ends free.
The outer wall of the nest is insulated with felt or mineral wool and a box made from pieces of antiseptic board is inserted into it. Its height is chosen such that an air gap (2-3 cm) is formed above the beam. Through it, water vapor accumulating in the wood will escape into the room in the baseboard area. This solution protects supporting part beams from rotting.
In practice, developers most often use a simpler method of sealing without the use of insulation and a wooden frame, covering the logs with cuttings of blocks or simply a raster.
The floor beams rest on, which is used to increase the spatial rigidity of the block masonry.
Internal load-bearing walls beams are sealed in a closed way. To increase the rigidity of the floor, they are connected through three to each other with steel anchor plates.
The section of the beam adjacent to smoke channel, insulated with asbestos or other non-flammable material. The main protection against fire here is a brick cut (thickening of the pipe masonry) 25 cm thick.
IN wooden houses Installation of beam floors is carried out in two ways:
- Cutting into log crowns;
- Through a steel shaped plate (chair), fixed to the wall using threaded rods.
Installation of ceilings by cutting into walls
Option to install beams on “chairs”
If top floor or the attic space will not be residential (heated), then it is necessary to insulate the wooden floors. To do this, insulation (mineral wool, ecowool) is placed in the space between the beams, having previously spread a layer of vapor barrier along the ceiling lining.
Polystyrene foam should not be used for this work for three reasons:
- It does not allow water vapor to pass through, and the wood underneath it rots;
- Does not isolate impact noise;
- It is problematic from an environmental point of view.
The design of the insulated floor is shown in the diagram.
The insulation of the ceiling of the first (ground) floor is carried out in the same way. The difference between them is that it is quite difficult to hem beams from below from a shallow underground. In this case, builders act differently. They tack a cranial block (5x5 cm) to the side edges of the beams. An antiseptic boardwalk is laid on it. It serves as a support for slab insulation, placed in the spaces between the bars. A vapor barrier is placed under the mineral wool. A vapor barrier is also laid on top of the beams. After this, logs are attached to them and the finished floor is installed on them.
The mineral wool slab should be placed between the beams as tightly as possible to prevent the floor from blowing through. For better insulation All insulation joints are treated with polyurethane foam.
Control of the horizontal installation of the beams is carried out using a bubble level laid on a flat, long board. For leveling, use cutting boards, protected bitumen mastic. They are placed under the ends of the beams.
Vapor barrier sheets should be laid with an overlap of at least 10 cm and all joints should be taped with construction tape.
To reduce impact noise, before installing the second floor floor joists, soundproofing tape 5 mm thick is laid along the beams. A waterproofing film is placed under the joists only if the second-level room is residential. It will protect the insulation from water entering when washing the floor. The technology for its installation is similar to laying a vapor barrier.
The final stage of installing a wooden floor is the installation of a subfloor made of boards, plywood or OSB boards using self-tapping screws. After completing this work, lay fine coating from laminate, linoleum, parquet and finishing the ceiling.
It is impossible to imagine buildings without floors, for the manufacture of which concrete mixture and reinforcement are used. Floors have increased strength and can withstand high stresses. Reinforced concrete elements structures are mounted various methods. In some cases, installation is carried out using reinforced concrete products manufactured at reinforced concrete factories. Using another technology, a monolithic floor slab is constructed, the basis of which is concrete mortar and reinforcement with a diameter of 8-12 mm. Consider the installation of a solid slab. Let's figure out how to take the first step correctly.
Prefabricated and monolithic floor slab - design options
When constructing residential and industrial buildings, builders construct different kinds reinforced concrete floors:
- prefabricated For their production it is used required amount standard reinforced concrete panels, manufactured under production conditions. The length of the slab is selected taking into account the required distance between capital walls. After laying using lifting equipment finished products they are anchored and the working seam between the ends of the panels is sealed;
- prefabricated monolithic. The technology for forming prefabricated monolithic type floors is similar to the method for arranging prefabricated structures. The finished slabs are laid on supports, the function of which is performed by the load-bearing walls of the building. After fixing the laid slabs with reinforcement, a concrete layer with a thickness of at least 100 mm is poured. The ceiling height includes the thickness of the slab and the height of the concrete poured on top;
- monolithic. To construct a single slab, no lifting equipment is required. The process of constructing a solid structure involves installing panel formwork, assembling and placing a reinforcement cage inside it, as well as subsequent pouring concrete mortar. It is important to correctly calculate the formwork taking into account the planned load on the floor. Having mastered the installation technology, it is easy to carry out all the work on your own.
Private developers prefer monolithic structures due to their simplicity, possibility self-construction, as well as the absence of the need to use lifting equipment. It is not necessary to construct panel formwork from wood if you decide to form. In this case, the lower surface of the ceiling, formed by the metal profile, does not require additional finishing. When choosing a type of reinforced concrete slab, follow the requirements project documentation and take into account the structure of the building.
Advantages and disadvantages of laying monolithic type floors
When planning the construction of a monolithic floor for own home or a summer residence, you should study in detail the advantages of a monolithic structure compared to a prefabricated and prefabricated-monolithic version and analyze its weaknesses.
The main advantages of a solid reinforced concrete floor slab:
- increased strength of monolithic reinforced concrete. In the design of a solid reinforced concrete base there are no seams and a joining zone, which are present in the prefabricated version of the floor;
- balancing the forces created by the weight of the building elements on the building box and foundation. The load is evenly transmitted along the entire perimeter of the supporting surface;
- the possibility of constructing floors of various shapes for the implementation of non-standard projects of original buildings. In this case, columns and load-bearing walls can be used as supporting elements;
In houses made of brick, concrete or concrete blocks, the floors are usually made of reinforced concrete - the possibility of implementing architects' plans related to the construction of remote-type balconies on a reinforced concrete ceiling console. An increased safety margin of such structures is guaranteed;
- rigidity monolithic slab, formed between the floors of the building. The one-piece structure does not have the ability to move in the transverse plane and longitudinal direction;
- possibility of implementation installation work with your own hands. There is no need to use crane equipment to lift heavy reinforced concrete slabs to the installation site.
The undeniable advantages of the one-piece design also include durability. The service life of a properly concreted floor exceeds a century.
Along with a set of advantages, there are a number of disadvantages:
- increase in duration construction work associated with the long-term increase in operational strength of the concrete mass;
- the need to use increased volumes concrete mixture, which is preferably poured in one go using a concrete pump.
An analysis of the advantages of the design and a study of the shortcomings allows us to assert that the monolithic floor is superior to the prefabricated version in most respects.
Installation of a monolithic ceiling - step-by-step technology
Installation work between floors of a building should be started only after a thorough study of the technology, which provides for the following stages of work:
Monolithic flooring has a number of advantages compared to flooring made from ready-made reinforced concrete slabs - Performing strength calculations of reinforced concrete slabs.
- Preparation of necessary building materials, tools and equipment.
- Assembly formwork structure and ensuring its tightness.
- Manufacturing a reinforcement cage and placing it inside the formwork.
- Preparation of concrete mixture and filling with ready-made formwork solution.
Each of these stages of work has its own characteristics. Let us dwell in more detail on the specifics of performing the main stages.
Perform load capacity calculations
All loads that act on monolithic reinforced concrete during operation are divided into the following types:
- ongoing efforts. These include loads that are created by the weight of the building box, the mass of the partitions inside the building, as well as the roof structure;
- variable loads. Their size is determined by weight utility networks, a mass of finishing elements, furniture. The amount of temporary loads also depends on the number of people inside the building.
The load capacity of monolithic slabs depends on the thickness of the reinforced concrete mass. To ensure the required safety margin of the slab at a load of 500 kg per 1 sq. m it is necessary to maintain a thickness of the reinforced concrete mass equal to 0.2 m, determined on the basis of special calculations. It is important to take into account the operating conditions of the slabs to prevent them from cracking.
Like everything related to construction, monolithic flooring begins with a project The accuracy of strength calculations is influenced by the following factors:
- the size of the design forces acting per unit area of the floor;
- marking of the concrete solution used;
- thickness of the formed reinforced concrete slab;
- the length and width of the structure spanning the space between floors.
Based on calculations, the cross-sectional size of the reinforcement is determined, which dampens bending moments and tensile forces. Without special engineering training, performing calculations on your own is problematic. Entrust the calculation operations to professional builders or perform the calculations online using a special calculator posted on professional websites.
How a panel frame is formed using permanent formwork
Formwork for a monolithic floor slab is made on the basis of the following building materials:
- moisture-resistant plywood, the thickness of which is 2-2.5 cm. Laminated coating plywood will make it easier to dismantle after the solution has hardened;
- smooth boards made from durable lumber. To assemble the shields, use boards whose thickness is 4-5 cm and width 18-20 cm;
- telescopic metal supports or ordinary logs with a diameter of 15 cm. Racks are used to ensure the immobility of the formwork;
- wooden beams used to support the formwork frame. The beams perform the function of transverse elements of the formwork structure.
To assemble the formwork, also prepare hardware and the necessary carpentry tools. Don't forget about construction level, allowing you to control the horizontality of the structure.
The construction of a monolithic floor slab assumes that concrete will be poured into horizontal formwork When assembling the formwork, follow the sequence of operations:
- Draw the level of placement of formwork panels on the wall surface.
- Install the supporting elements with an interval of 100 cm between them.
- Place metal profiles or cross bars on vertical supports.
- Lay out plywood sheets or prepared boards and secure them firmly.
- Nail a vertical edging along the contour of the formwork structure.
- Check for horizontal alignment and seal the joint areas.
The formwork structure must be dismantled 4 weeks after concreting.
How to properly reinforce a monolithic floor slab
You should prepare in advance for carrying out reinforcement work. The following materials will be required:
- special linings that ensure a fixed position of steel reinforcement relative to the outer surface of the concrete mass;
- corrugated reinforcement with a bar cross-sectional diameter of up to 12 mm, increasing the ability of concrete to absorb loads;
- a knitting device and annealed wire, allowing you to quickly fix the elements of the reinforcement frame.
To facilitate bending operations you will need special device. Cut the workpieces using a grinder equipped with a cutting wheel for metal.
After the formwork is arranged, a reinforcement frame made of two meshes is installed in it Produce the reinforcement grid according to the given algorithm:
- Cut the steel reinforcement into bars of the specified length.
- Place the longitudinal blanks on the clamps in increments of 15-20 cm.
- Bind cross bars, observing the specified interval.
- Tie vertical reinforcement to the connected lattice every 100 cm.
- Tie the mesh top level and carefully secure it to the supports.
When connecting reinforcement to the ceiling, maintain an overlap of 35 times the diameter of the rods.
How to pour slabs onto load-bearing walls of a house
The monolithic floor slab is poured with a concrete mixture prepared from the following ingredients:
- Portland cement marked M400;
- gravel or crushed stone up to 3 cm in size;
- purified sand.
All components of the solution are mixed with water until a creamy concrete is obtained. To increase the efficiency of mixing, a concrete mixer is used. However, given the need for an increased volume of the mixture, it is worth buying ready-made concrete, which is delivered to the work site in a special mixer.
The concreting process includes the following steps:
- Supplying the concrete mixture into the formwork with reinforcement.
- Uniform distribution of concrete over the area of the future floor.
- Compacting a concrete mass using a mechanical vibrator.
At the final stage, the surface is leveled. Concrete gains operational strength within one month and requires additional moisture. After all, during the hardening process of concrete, moisture gradually evaporates. To maintain constant humidity and prevent cracking, the surface is covered with plastic film and regularly moistened.
Conclusion
Having familiarized yourself in detail with the features of the technology, it is not difficult to install a monolithic ceiling for a private house, cottage or summer house on your own. Significant savings can be achieved by doing the work yourself Money. It is important to use a high-quality concrete mixture and correctly reinforce the floor. Before starting construction activities, it is advisable to consult with professional builders who will always help with advice.
Pouring a monolithic interfloor slab is not the easiest, but it is a truly universal and time-tested method. In this article we will talk about the main structural features and stages of floor construction, as well as types of formwork, including permanent formwork.
Typology of buildings and scope of application
The main areas of application of monolithic floors are buildings with load-bearing walls made of brick, block masonry or concrete panels, as well as domed houses. Requirements for the solidity of the floor may be determined by:
- non-standard building plan;
- the need to significantly increase the load-bearing capacity of the floor;
- increased requirements for hydro- and noise insulation;
- the need to provide an open layout;
- reducing costs for interior decoration.
Pouring is usually done after the construction of the walls of the first floor is completed. However, options for pouring monolithic floors already in buildings with roofs are possible, if weather or other conditions require it. In this case, they install on the masonry of the lower floor I-beams and along the perimeter of the load-bearing walls a crown is poured to the height of the ceiling. Also, to strengthen mechanical connections, with inside The crown is produced with 40-50 cm embedded reinforcement. Its total cross-section cannot be less than 0.4% of the cross-section of the longitudinal section of the crown.
Design calculations of the supporting structure
When choosing the span length, it should be related to the slab thickness as 30:1. However, when designing independently, there is practically no point in making a floor thicker than 400 mm, since load bearing capacity structure increases along with its own weight and static stresses. Therefore, the permissible load on homemade floors rarely exceeds 1500-2000 kg/m2.
The situation can be corrected by including in load-bearing structure I-beams laid on concrete-lined masonry surfaces of load-bearing walls. Another way to increase the span while maintaining relative freedom of layout is to support the floor on columns. With a monolithic structure thickness of up to 400 mm and a span length in four directions from the columns of up to 12 meters, the cross-sectional area of the support is 1-1.35 m2, provided that the cross-section of the embedded reinforcement in the column is at least 1.4%.
Calculation of reinforcement of a monolithic slab
IN general case The thickness of the slab is determined by the amount of reinforcing steel that is embedded in it. Reinforcement density, in turn, depends on the maximum permissible load and resistance to cracking. Avoiding special cases, we can give general example design demonstrating full compliance regulatory requirements with a sufficiently high safety margin.
In private construction, reinforced concrete is reinforced with reinforcement with a periodic profile of class A400, also known as A-III.
Diameter of rods in slabs of thickness:
- up to 150 mm - at least 10-12 mm;
- from 150 to 250 mm - at least 12-14 mm;
- from 250 to 400 mm - at least 14-16 mm.
The reinforcement is laid in two meshes with a mesh size of 120-160 mm, the thickness of the protective layer of concrete from the edges of the slab is at least 80-120 mm, and at the top and bottom at least 40 mm. The direction of laying four rows of reinforcement, starting from the bottom: along, across, across, along. For dressing, galvanized wire with a thickness of at least 2 mm is used.
Installation of different types of formwork
The formwork must withstand a load of 500-1100 kg/m2, including the dynamic impact of falling concrete. To create a formwork plane the following can be used:
- Plastic sheets of reusable formwork.
- Moisture-resistant plywood thickness 17-23 mm.
- OSB 20-26 mm thick.
The edges of the slabs must fit tightly to the walls; the use of formwork with gaps at the joints of more than 2 mm is not allowed unless it is planned to cover the surface with a waterproofing film.
Sometimes it is reasonable to make the formwork permanent, using profiled sheets, orienting them with a narrow flange down. They are placed along the slab so that the waves during pouring form numerous stiffening ribs. The thickness is calculated from the bottom rib, thus saving the concrete mixture by 20-25%. In this case, the height of the ridge should not exceed a third of the total thickness of the slab. If the formwork is not planned to be removed, self-tapping screws with a rubber washer are screwed into it and tied with thin wire to the reinforcement.
Installation of formwork begins with the placement of racks: these can be either steel telescopic racks with a tripod and a unifork, or flawless wood with a cross-section of at least 100 cm 2. Each post should be connected to two adjacent 1-inch plank slants. The racks are mounted along the lines of the beams, the distance between which, depending on the thickness of the slab 150-400 mm, is:
- 190-240 cm with plywood thickness up to 20 mm;
- 210-260 cm with a plywood thickness of 21 cm.
In this case, the distance between the racks of one beam, depending on the gap between them, is:
- from 140 to 200 cm with a span of up to 150 cm;
- from 120 to 180 cm with a span of 160-210 cm;
- from 100 to 140 cm with a span of 210-250 cm.
The main beams are usually made of 100x100 mm timber. Secondary beams, which have a cross-section of 50% of the main ones, are laid across them in increments of 500-650 cm. If the formwork is made of profiled sheets, the pitch of the secondary beams is equal to 3.5 times the distance between the waves.
Vertical formwork is mounted from retaining panels attached to external wall building. Often, 80-100 mm thick aerated concrete blocks are laid around the perimeter to hide the ceiling belt.
Reinforcement and strapping
After installing the formwork, it is lubricated with an anti-adhesive compound and the installation of reinforcement begins. On the crowns and supporting ribs, the rods are tied into a square, maintaining the minimum permissible on all sides protective layer. The main floor mass is reinforced with mesh. The bottom layer is placed on plastic “crackers” that control the preservation of the bottom protective layer. The mesh is tied at the intersection of every third rod.
After tying the bottom mesh, intermediate clamps are installed on it every 100 cm in a checkerboard pattern. To strengthen the support, end clamps are mounted on the walls. These elements help maintain the design distance between two reinforcement planes.
The mounted upper mesh is connected to the lower connecting brackets. After installation is completed, the reinforcing structure should be as one whole and easily absorb the load from people walking on it.
Pouring concrete
Monolithic floors are poured with concrete grade B20-B30, prepared in factory conditions. Filling monolithic floors should be carried out in one stage, so filling the space in small doses is not recommended. If it is impossible to complete the entire amount of work at once, sections of the slab must be cut with a mesh with a mesh size of 8-10 mm.
The mixture can be supplied to the ceiling using a concrete pump or a large bucket lifted by a crane. After serving on top, the mixture is evenly distributed, vibration-set and left to harden.
Further actions
Concrete gains sufficient strength after 4 weeks, during which time it needs periodic wetting and protection from rain for the first 2 days. After drying, the formwork can be removed and the construction of walls can begin.
Monolithic reinforced concrete floors are still of limited use due to their high labor intensity. They are used in cases where it is necessary to cover an atypical room with atypical dimensions, as well as in monolithic buildings.
Monolithic floors are made with beams (ribbed) and without beams in the form of a smooth slab (Fig. 5.4).
Fig.5.4. Structural diagrams of monolithic reinforced concrete floors:
a – ribbed; b – caisson; c – beamless; 1 – plate; 2 – beams; 3 – columns; 4 – column capital
5.1.4. Floors on beams
Beam floors are used in low-rise construction (in wooden and stone buildings), during the reconstruction of old buildings by replacing wooden beams with more durable metal or reinforced concrete ones.
Based on the material, beams are divided into wooden, reinforced concrete and metal.
Floors on reinforced concrete beams. Floors on reinforced concrete beams consist of beams laid on load-bearing walls with axial distances of 600, 800, 1000 mm, inter-beam filling and a floor (Fig. 5.5).
The depth of support of the ends of the beams on the walls or purlins is taken to be at least 150 mm. The ends of the beams on the supports are anchored, and the gaps between the beam and the walls of the nest to a depth of 40-60 mm are sealed with mortar. The inter-beam filling (Fig. 5.6) consists of a ramp, which is a flooring of lightweight concrete slabs and a sound-insulating (heat-insulating) layer. The seams between the knurling elements and the beams are carefully filled with mortar or glassine is laid on top of the knurling. Sound insulation is usually made from a layer of slag or sand at least 60 mm thick. The bottom edge and beams are rubbed with mortar. This design is used when plank floors by lags. When installing other types of floors, for example cement, requiring a continuous gesture
Fig.5.5. Prefabricated reinforced concrete beams and their supporting parts:
a – plan for the location of floor beams; b – general form beams; 1 – beam;
2 – steel anchor; 3 – steel structure; 4 – mounting loop; 5 – sealing with concrete
After preparation, the space between the beams is filled with slag, on which a layer of slag concrete with a thickness of at least 40 mm and a floor are laid (Fig. 5.6d). More appropriate in these cases are roll-ups made of double-hollow lightweight concrete stones - liners, which have sufficient sound-proofing properties and require only careful filling of the joints with mortar (Fig. 5.6 d).
Floors according to metal beams. Currently, metal beams are used only in exceptional cases during the repair and reconstruction of buildings.
Steel beams (usually I-beams) are located at a distance of 1-1.5 m from each other. The depth of support of their ends on the walls is 200-250 mm.
Fig.5.6. Design beam floor from prefabricated
reinforced concrete elements:
a – general view; b – lightweight concrete slab; c – lightweight concrete liner stone; d,e – flooring options with mineral floors; 1 – reinforced concrete beam; 2 – roll made of lightweight concrete slabs; 3 – waterproofing layer; 4 – sound insulation; 5 – soundproofing gasket; 6 – lags; 7 – plank floor; 8 – slag; 9 – slag concrete thickness
40 mm; 10 – cement floor 20 mm thick; 11 – grouting with mortar
To increase the area of pressure on the masonry in order to protect it from crushing, concrete pads or steel pads are placed under the ends of the beams. The ends of the beams are anchored into the masonry walls and, if necessary, insulated with felt, followed by sealing the gaps around the perimeter of the nest with concrete (Fig. 5.7).
The inter-beam filling can be made from prefabricated reinforced concrete or monolithic slabs, and in some cases from brick vaults.
Fig.5.7. Floor construction on steel beams:
a – supporting the ends of the beams on the walls; b – anchor fastening detail; c – floor filled with reinforced concrete monolithic slab; d – the same, with brick vaults;
1 – steel beam; 2 – steel anchor; 3 – concrete pad; 4 – bolt; 5 – sealing with cement mortar; 6 – reinforced concrete monolithic slab; 7 – lightweight concrete; 8 – ceramic tiles over a layer of cement mortar; 9 – brick vault; 10 – soundproofing layer; 11 – two layers of roofing felt; 12 – plank floor along joists; 13 – steel mesh; 14 – plastering with cement mortar
Floors on wooden beams. Currently, wooden floors can only be used in low-rise buildings and only in areas where wood is a local building material. Their advantages are the simplicity of the device and relatively low cost. Disadvantages are combustibility, the possibility of rotting and relatively low strength.
All wooden floor elements are made from coniferous species forests (pine, larch, spruce, etc.) Beams are made mainly in the form of rectangular beams, the dimensions of which are determined by calculation. (Fig. 5.8). The distance between the axes of the beams is taken from 600 to 1000 mm.
To support the inter-beam filling, bars with a cross-section of 40 x 50 mm, called cranial ones, are nailed to the sides of the beams (Fig. 5.8). The depth of support of the ends of the beams in the nests of stone walls must be at least 150 mm (Fig. 5.9). The ends of the beams are antiseptic with a 3% solution of sodium fluoride or coated (except for the ends) with resin, and when embedded in external walls, they are additionally wrapped in two layers of roofing felt. On internal walls or purlins, two layers of roofing felt with tar mastic are laid under the ends of the beams. The gaps between the walls of the nest and the ends of the beams to a depth of 40-60 mm are tightly sealed with mortar. The arrangement of wooden floor beams, as well as their anchoring, are similar to reinforced concrete beam-type floors (Fig. 5.1 c).
The filling between the beams (Fig. 5.10) consists of a panel board roll, lubrication along the top of the roll with a clay-sand solution 20-30 mm thick and a soundproofing layer of slag or calcined earth 60 mm thick. The floors are made of planks on joists with metal ventilation grilles installed in the corners of the rooms. The ceilings are plastered with lime-gypsum mortar over the shingles or hemmed with sheets of dry plaster.
Fig.5.8. Structural solutions for wooden beams:
1 – single beam beam; 2 – a beam composed of two solid wood blocks; 3 – beam made of laminated wood; 4 – cranial block
Rice. 5.9. Details of supporting wooden floor beams on
stone walls:
a - on outer wall; b – on the inside; 1 – external load-bearing wall; 2 – external self-supporting wall; 3 – internal load-bearing wall; 4 – wooden beam; 5 – thermal insert; 6 – two layers of roofing felt on tar mastic or an antiseptic zone of the beam; 7 – anchor made of strip iron; 8 – crutches or nails
Fig.5.10. Floor construction on wooden beams:
a – with a plank shield roll; b – the same, from hollow blocks; c – the same, from lightweight concrete blocks (slabs); d – floors in bathrooms; d – types of roll-ups; 1 – beams; 2 – roll-up (panel); 3 – plaster; 4 – clay lubricant; 5 – backfill; 6 – lags; 7 – soundproofing gasket; 8 – plank floor; 9 – hollow lightweight concrete block; 10 – cranial block; 11 – solution; 12 – gypsum board; 13 – floor made of ceramic tiles; 14 - cement strainer 20 mm; 15 – concrete preparation; 16 – two layers of roofing felt on mastic; 17 – plank floor; 18 – plates; 19 – boards; 20 – false ceiling
In this article we will look at the main types of floors and the materials from which these floors are constructed. So, what are overlaps? Floors are a structure that divides adjacent rooms in height, that is, it forms floors and separates them from attics and basements.
Basic requirements for floors
- Floors must have sufficient strength to withstand the load both from its own weight and useful (furniture, equipment, people in the room, etc.).The amount of payload per 1 m2 of flooring is set depending on the purpose of the room and the nature of its equipment. For attic floors, the payload should be no more than 105 kg/m2, and for basement and interfloor floors 210 kg/m2.
- The ceiling must be rigid, that is, it must not deflect under loads (the permissible value is from 1/200 for attic floors to 1/250 of the span for interfloor floors).
- When installing the floor, a sufficient degree of sound insulation must be provided, the amount of which is established by standards or special recommendations for the design of buildings for a particular purpose. To do this, it is necessary to carefully close the gaps in the places where the material joins, in order to avoid the transfer of sound from neighboring rooms located above or below.
- Ceilings separating rooms with a temperature difference of 10 degrees Celsius (for example, separating cold basement from the first floor or attic from the first floor), must meet the requirements of thermal protection, that is, it is necessary to increase the layer of thermal insulation.
- No floor structure, especially wood, can withstand prolonged exposure to fire, but each material has its own fire resistance limit. The fire resistance limit of reinforced concrete floors is 60 minutes; wooden floors with backfill and lower plastered surface - 45 minutes; wooden floors protected with plaster, about 15 minutes; There are even fewer wooden floors not protected by fireproof materials.
Types of house floors
- interfloor (separating residential floors, including the attic),
- basement (separating the basement from the residential floor),
- basement (separating the residential floor from the cold underground),
- attic (separating the residential floor from the unheated attic).
In my own way constructive solution The load-bearing part of the floors can be divided into:
- beams, consisting of a load-bearing part (beams) and filling;
- beamless, made from homogeneous elements (flooring slabs or flooring panels).
Types of floors for the home
Beam floors
In beam floors, the load-bearing base consists of beams located at the same distance from each other, onto which filling elements are laid that perform enclosing functions. Beams can be wooden, reinforced concrete or metal.
Floors made of wooden beams
In private housing construction, the most popular are wooden beam floors, usually used in wooden and frame houses.
For wooden beams there is a limitation on the width of the span (room). They can be used for:
- interfloor ceilings - with a span width of 5 meters;
- for attic floors (when not in use attic) with a span width of up to 6 meters. Metal beams can be used for any span width.
The wooden floor is made from wooden beams of coniferous and hardwood. On the upper side of the beams there is a flooring, which also serves as the floor. The structure of the beam floor consists of the beams themselves, the run-up, the floor and the insulation.
With a rectangular house plan, it is advisable to block the span along the short wall.
Scheme for laying floor slabs along a short wall
To prevent beams from bending under the weight of the floor, they must be placed at a certain distance (see table). The section of the beam is determined based on the load falling on it.
For example: You need to build a floor measuring 3.0 * 4.0 m. We lay wooden beams (section 6x20) along a wall equal to 3.0 meters. If the floor is interfloor, the beams are laid at a distance of 1.25 m from each other, if the attic floor is 1.85 m. That is, the greater the span width of the future floor, the smaller the distance between the beams will be, since large area ceilings, there are more loads.
The distance between the beams is also affected by the thickness of the floor boards. If they are 28 mm or less thick, the distance between the beams should not exceed 50 cm.
Advantages of wooden flooring:
- The main advantage is that a wooden floor can be quickly and easily installed in any (even difficult) place, without the use of any special means, that is, you can do without a crane and other equipment. The wooden floor is light and relatively inexpensive.
Disadvantages of wooden flooring:
- The main disadvantage of wooden floors is the increased flammability, sometimes the possibility of rotting and infection with bark beetles.
Wooden floor installation technology:
Installation of beams: Before installing the beam, it must be treated with an antiseptic solution. If the beams rest on stone or concrete wall, then its ends must be wrapped in two layers of roofing material. The beam is inserted into the nest prepared during the construction of the wall. When inserted into the nest, the beam should not reach the rear wall by 2-3 cm. The end of the beam is made beveled.
Beam installation diagram
(1 - beam, 2 - roofing felt, 3 - insulation, 4 - mortar).
The remaining free space in the nest is filled with insulation; you can fill it with polyurethane foam.
Installation of rewind: Bars (section 4x4 or 5x5), which are called cranial, are nailed to the side faces of the beams.
Scheme of rolling wooden panels
(1 - wooden beam, 2 - cranial block, 3 - roll-up shield, 4 - vapor barrier, 5 - insulation, 6 - finished floor finishing, 7 - ceiling finishing).
A roll of wooden panels is attached to these bars. The roll-up is made from boards made of longitudinal boards or boards from transverse boards. The knurling plates must be pressed tightly against each other. They are attached to the cranial block with self-tapping screws. The roll-up serves as preparation for attaching a “clean” ceiling.
Insulation gasket: An integral part of a wooden beam floor is insulation, which primarily performs the role of sound insulation in the interfloor ceiling, and also serves as thermal insulation in the attic floor. First of all, you need to decide what material to use. The insulation material can be mineral wool, polystyrene foam, slag, perlite, expanded clay, as well as dry sand, sawdust, shavings, straw, and wood leaves. Mineral wool is a lightweight material, easy to work with, unlike foam plastic, it “breathes”, has sufficient heat and sound insulation, in general, in most cases, wool is suitable for both insulating interfloor and attic floors. Expanded clay (fraction 5-10 mm) - heavier material mineral wool, which makes the structure heavier (the weight of 1 m2 of expanded clay is from 270-360 kg).
After fixing the bead, a layer of thermal insulation is placed on top of it. First, a layer of roofing felt, glassine or vapor barrier film is laid between the beams, bending it about 5 cm onto the beams and we proceed to thermal insulation. The thickness of any insulation, for interfloor covering should be at least 100 mm, and for the attic floor, that is, between a cold and heated room - 200-250 mm.
Cost and consumption of materials: The consumption of timber for traditional wooden floors is approximately 0.1 m3 per 1 m2 of flooring at a depth of 400 cm. The average cost of a cubic meter of wooden beams is from 145 dollars (or 14 dollars per linear meter). And the cost of the boards will cost you about $200 per cubic meter. Costs for 1 square meter of flooring using wooden beams range from $70 and above.
Floors on metal beams
Compared to wooden ones, they are quite reliable and more durable, and also have a smaller thickness (save space), but such floors are rarely erected. To fill the openings between the beams, you can use lightweight concrete inserts, lightweight reinforced concrete slabs, wooden panels or wooden slabs. The weight of 1 m2 of such flooring often exceeds 400 kg.
Advantages:
- A metal beam can cover large spans (4-6 meters or more).
- The metal beam is non-flammable and resistant to biological influences (rot, etc.).
But flooring with metal beams is not without its drawbacks:
- In places of high humidity, corrosion forms on the metal.
- In addition, such floors have reduced heat and sound insulation qualities. To mitigate this disadvantage, the ends of the metal beams are wrapped in felt. In such floors, the load-bearing element is a rolled profile: I-beam, channel, corners.
Rolling profile
Prefabricated reinforced concrete hollow slabs 9 cm thick are laid between the beams. A layer of slag and reinforced concrete screed 8-10 cm thick is applied over the reinforced concrete slabs. Steel consumption is high - 25-30 kg/m2, depending on the grade of steel from which the beams are made.
Scheme of the design of a prefabricated reinforced concrete floor slab on metal beams
1 - “clean” floor; 2 - boardwalk; 3 - beam; 4 - prefabricated reinforced concrete slab; 5 - waterproofing; 6 - plaster mesh; 7 - plaster.
Material cost: The price of a steel profile ranges from 7 to 18 dollars per linear meter. The cost of lightweight reinforced concrete slabs is from $110 per piece. For 1 square meter of flooring on metal beams you will spend from $100 and more.
Floors made of reinforced concrete beams
They are installed on spans from 3 m to 7.5 meters. The work is complicated by the need to use lifting equipment. The weight of such beams is 175 - 400 kg.
Advantages:
- With the help of reinforced concrete beams you can span larger spans than with wooden ones.
Flaws:
- To install the floor on reinforced concrete beams, it is necessary to use lifting equipment.
Installation: Reinforced concrete beams are laid at a distance of 600-1000 mm. The filling of the interbeam space is arranged in the form of lightweight concrete slabs or hollow lightweight concrete blocks (for plank or parquet floors, slabs are used, and for linoleum or parquet floors, concrete base- hollow blocks).
Scheme of the design of a lightweight concrete slab on reinforced concrete beams
(1 - reinforced concrete beam, 2 - lightweight concrete slab, 3 - cement screed and substrate, 4 - parquet, laminate)
Scheme of the design of a floor slab made of hollow blocks on reinforced concrete beams
(1 - reinforced concrete beam, 2 - hollow blocks, 3 - cement screed, 4 - linoleum)
The seams between the beams and slabs are filled with cement mortar and rubbed. Attic floors be sure to insulate, soundproof between floors, basement floors also insulated.
Floor slabs made of hollow blocks on reinforced concrete beams
Cost: For one linear meter of beam you will have to pay from 25 dollars. The price for one lightweight concrete block is from 1.5 dollars. As a result, for 1 square meter of flooring on reinforced concrete beams you will spend from 65 dollars.
Beamless floors
They are homogeneous elements (slabs or panels) laid close to each other or a solid monolithic slab, which simultaneously serve as load-bearing and enclosing structures. Depending on the manufacturing technology, beamless floors can be prefabricated, monolithic or prefabricated monolithic.
Prefabricated reinforced concrete floors
The most popular, especially in brick houses. To install reinforced concrete floors, two types of panels are used: solid (they are made mainly from lightweight concrete) and hollow-core. The latter have round holes kind of “stiffening ribs”. Panels are selected depending on the width of the span to be covered and load-bearing capacity.
Advantages:
- Reinforced concrete slabs have high strength and are designed for a payload of over 200 kg/m2.
- Unlike wood, concrete is not afraid of dampness and does not require any maintenance.
Flaws:
- When installing floors made of reinforced concrete slabs, lifting equipment is required.
- Buy ready-made slabs the right size not always possible, since they are made in standard sizes at the factory.
Scheme of a beamless floor for a house
Installation: Floor slabs are laid on a layer cement mortar grade 100. The support of the slabs on the walls (walls more than 250 mm thick) must be at least 100 mm. The seams between the slabs must be cleared of debris and thoroughly filled with cement mortar.
Approximate cost of the material: The cost of one floor slab starts from $110. For 1 square meter of flooring made of reinforced concrete slabs you will spend at least 35-40 dollars.
Monolithic reinforced concrete floors
Can be various shapes. Monolithic reinforced concrete floors are a solid monolithic slab 8-12 cm thick made of grade 200 concrete, supported by load-bearing walls. The weight of a square meter of a monolithic floor with a thickness of 200 mm is 480-500 kg.
Photo of reinforcement of a monolithic reinforced concrete floor
Installation of monolithic floors is carried out in four stages:
- Installation of steel load-bearing beams in prepared places;
- Hanging device wooden formwork from unedged boards (suspended from steel beams);
Installation of suspended wooden formwork from unedged boards
- U masonry reinforcement (diameter 6-12 mm);
- Concreting the floor slab with M200 concrete.
Advantages of a monolith:
- No costly handling and higher quality concrete surface, which does not require sealing of seams, as well as the ability to implement complex architectural and planning solutions.
The disadvantages of monolithic floors include the need to install wooden formwork over almost the entire area of the future floor. However, this does not mean that the formwork needs to be installed all at once. The overlap can be done in separate spans, moving the formwork as the concrete sets.
Installation: Before proceeding with the installation of the ceiling, it is necessary to construct the formwork (it can be purchased ready-made or rented), which consists of telescopic racks, tripods, uniforks, beams, flooring and plywood. Formwork made of wooden and aluminum beams allows you to form floors of any configuration - rectangular, cantilever and even round. To the top wooden part The beams are overlaid with sheets of plywood to form the formwork for pouring the concrete. Next, the reinforcement frame is installed and secured. The ends of steel rods 60-80 cm long are bent and tied with wire and reinforcement. Then, concreting is carried out over the entire area of the ceiling to a height of 10-30 cm. Complete adhesion of the concrete occurs after 28 days.
Formwork for a monolithic floor slab made of wood flooring and plywood
Installation of a reinforcement cage in the formwork for the construction of a monolithic reinforced concrete slab
Approximate cost of material: The cost of floor formwork, with wooden and aluminum beams, starts from $40. The approximate consumption of reinforcement for the floor is 75-100 kg/m3 of concrete. The cost of 1 ton of reinforcement is $650. The cost of 1 cubic meter of ready-made concrete is from $130. As a result, the price for 1 square meter of monolithic flooring will cost you from $45 and above (without the cost of formwork).
Prefabricated monolithic floor
More modern solution on the installation of floors. The bottom line is that the space between the floor beams is filled with hollow blocks, after which the entire structure is poured on top with a layer of concrete.
Prefabricated monolithic flooring for a house
Advantages:
- Installation without application lifting mechanisms, improvement of thermal insulation properties, possibility of overlapping complex shape, reducing construction time.
Flaws:
- The disadvantages include that the prefabricated monolithic structure has a labor-intensive (manual) installation process, which is not advisable when building a house with 2-3 floors.
Installation: During installation, prefabricated monolithic floor beams are laid on the walls at intervals of 600 mm. Weight linear meter beams do not exceed 19 kg. This allows, in most cases, the installation of beams without the use of a crane. Hollow blocks are laid manually on the beams. Weight expanded clay concrete block- 14 kg, polystyrene concrete - 5.5 kg. As a result, the dead weight of one square meter of the original floor structures is 140 kg for expanded clay concrete blocks and 80 kg for polystyrene concrete blocks.
The floor structure prepared in this way performs the function permanent formwork, on which the layer is laid monolithic concrete class B15 (M200).
Before pouring concrete, it is necessary to reinforce the structure with reinforcing mesh with cells measuring 100x100 mm made of wire with a diameter of 5-6 mm.
The weight of one square meter of finished flooring is 370-390 kg for expanded clay concrete blocks and 290-300 kg for polystyrene concrete blocks.
Expanded clay concrete block for prefabricated monolithic flooring
Approximate cost: The cost of prefabricated monolithic floor structures (beams and blocks) will cost you 40-50 dollars/m2. The cost of finished floor structures (beams + blocks + mesh + concrete) is 70-75 dollars/m2.
Thermal and sound insulation of floors:
The thermal protection of the ceiling must be such that the temperature on the floor surface is close to the internal air temperature and does not fall below it by more than 2°C. To avoid dampness between heated and unheated rooms, a layer of glassine should be placed above the thermal insulation to protect the insulation layer from moisture.
Laying scheme for heat and soundproofing materials into the ceiling
(1 - wooden beam, 2 - skull block, 3 - roll, 4 - layer of insulation, 5 - vapor barrier film or glassine, 6 - boards)
In addition to good thermal protection, floors must also provide sufficient sound insulation of the premises. In accordance with current standards (data for the Russian Federation), the insulation index Rw must be equal to or greater than 49 dB.
For hollow-core reinforced concrete slabs with a thickness of 220 mm, the insulation index is Rw = 52 dB.
For wooden floors (280 mm insulation layer + one 12 mm layer of plasterboard) the sound insulation index is 47 dB.
Now a little about insulation. Ready-made mineral wool slabs performed well as thermal insulation. In addition to the well-known insulation with ready-made mineral wool slabs, there are alternative options, carried out on site. For example: You can pour slag or ordinary sawdust. By the way, they are 4 times lighter than slag and at the same time provide 3 times better thermal insulation with the same layer thickness. Yes, when winter temperature at -20°C, the backfill of slag should be 16 cm thick, shavings - 7, and sawdust - only 5 cm.
You can make sawdust concrete slabs for the same purpose yourself. To do this, you can take 1 volume part of sawdust, 1.5 parts of lime mortar or 4 parts of clay, 0.3 parts of cement and from 2 to 2.5 parts of water. The finished slabs are dried in the shade, laid on a roofing felt pad, the seams are sealed with clay or lime mortar. Square meter such a slab weighs about 5-6 kg with a thickness of 10 cm.
What kind of flooring should you choose for your home? It all depends on the type of house, as well as on the installation technology and price of this ceiling. To conclude this article, I will provide a table in which you can compare different types of floors and choose the most suitable one for yourself.
Attention: Prices in this article are presented for the period of 2008. Be careful!
