How to reinforce the floor under the screed. Draft floor screed on the ground: manufacturing features, procedure and step-by-step instructions Floor on the ground mesh reinforcement

But it is not without a number of shortcomings. If you forget to make vents in the strip foundation (or incorrectly calculate their cross section), then over time this can lead to problems. Due to insufficient ventilation of the underground, wooden logs become covered with fungus, mold and rot. Excess moisture in the basement also leads to the destruction of the concrete floors of the floor of the first floor.

To avoid this, you can replace traditional vents with a closed ventilated underground. This is detailed in the article. “Do I need air in the basement” . But there is another option - to abandon the underground and build a floor on the ground on the basis of a strip foundation, as FORUMHOUSE experts advise.

Floors on the ground: what is itsuch

This design is a monolithic concrete base (screed). Here is the device of the floor on the ground: the screed is poured inside the perimeter of the strip foundation onto well-compacted soil, with which the sinuses of the foundation and the insulation layer are covered. Underfloor heating can be installed together with a concrete base. This design accumulates heat, so it is well suited as an element of an energy-efficient home.

The composition of the floor on the ground for a residential building.

There are the following options for floors on the ground:

1. On the prepared base (well-compacted soil), a floor slab is poured, rigidly connected to the strip foundation;
2. A floor slab is poured onto the prepared base, which is not connected to the strip foundation, the so-called "floating" screed.

Let's take a closer look at the pros and cons of these options.

Michael1974:

- If you fill in a “floating” screed, then the construction of the tape and the floor is “untied”. If shrinkage occurs, then the floor screed structure on the ground will “play” regardless of the foundation, cracks will not appear in the structure, because. no stress. This is a plus. But there is also a minus - the design "lives its own life", separate from all other structures.

Floor device on the ground.

With a rigid structure, the foundation / screed unit works as a single unit. The screed will not shrink, because lies on the foundation. But if the soil is not compacted well enough, after a while it may sink, and the screed will “hang” in the air. Under heavy load, if there are walls, partitions, supporting elements on the screed, this can lead to deformation of the base, cracks and loss of the bearing capacity of the entire floor structure on the ground.

How to make a floor on the ground

Both screed options have both pros and cons. The quality of the concrete floors on the bulk soil depends largely on the quality of the compaction of the bulk soil and on how correct the design will turn out.

Michael1974:

– When pouring a “floating” screed, the “foundation wall / screed” assembly must really be untied, otherwise the structure may be pinched in the tape frame. Those. the floor inside the tape frame must move relatively freely, otherwise the whole point of the floating screed is lost.

To do this, a damper is made of an elastic material between the screed and the foundation (wall), which restores its original shape after the load is removed - in this case, it is appropriate to place an isolon with a thickness of 8-10 mm. This will allow the concrete screed to “float” freely and compensate for its thermal expansion.

A common mistake is to tie all nodes as tightly as possible. As a result, increased loads occur in the structures. In the case of a floating screed, the "floor" and "foundation" elements work independently of each other.

Ground floor: device.Basic principles

An important rule: a well-prepared base is the key to a long service life of the entire structure. The filling base (the best backfilling of the floor on the ground is sand) must be spilled with water and carefully compacted in layers of 10-15 cm.

Due to the backfilling of crushed stone, when the rammer passes through it, a local impact occurs, as a result, there is a deep additional compaction of the soil layers lying at the lower levels. It is worth building up attention on the correct method of tamping sand.

- In all instructions for vibrating plates it is written that the plate compacts sand to a depth of 20-30 cm, but how well this layer is compacted, I doubt that it is enough. Therefore, I believe that for reinsurance it is better to compact the sand in layers of about 10 cm. It looks like this:

• We spread the sand in a layer of 10-15 cm;
• We pass through the sand with a vibrating plate "dry";
• Spill sand with water from a hose. It is necessary to do this not with a jet of water, so as not to break the layer, but through a spray nozzle;

It is necessary to spill water so that the sand is wet, but not oversaturated with moisture. If the amount of water is too large, then the sand base is practically not rammed.

• We pass through the moistened sand with a vibrating plate 2 times with a change in the orientation of movement;
• Spill the sand with water again;
• We pass along the moistened sand with a vibrating plate 2-3 more times with a change in the direction of movement.

What kind of waterproofing to put on the floor on the ground

After thorough preparation of the base, we proceed to laying the hydro-vapor barrier, which will protect the floor structure from moisture. It is often asked whether it is necessary to make a footing before laying this layer. After all, welded or glued waterproofing, in order to avoid damage, must be placed on a flat, rigid base.

When arranging a concrete floor in a private house, the option of laying them on the ground with simultaneous insulation is most often chosen. This method makes it possible to obtain a durable monolithic screed, suitable for laying any floor covering, at medium investment and labor costs, and to prevent heat loss through the bottom of the building. All stages of work can be done by hand, the mandatory requirements of the technology include the correct alternation and sufficient thickness of the layers of the cake.

The design is a multi-layer cake, laid on dry and stable soil layers, taking into account a pre-measured level. The mandatory conditions for its construction include GWL below 4.5-5 m, the presence of an established foundation and constant heating. The standard scheme includes the following layers (from bottom to top):

1. Compacted soil, by analogy with a monolithic slab, accepting the main weight loads.

2. At least 10 cm of sand, which reduces the forces of frost heaving of the soil and performs drainage functions.

3. From 10 cm or more of compacted crushed stone and / or expanded clay, distributing weight loads and preventing subsidence and displacement of the remaining layers of the floor.

4. Flooring of waterproofing materials, combining two functions of protection: from capillary moisture and water loss when pouring the solution. In this case, it is the roll varieties that are laid with a mandatory overlap of 10 cm and above that have the optimal characteristics.

5. Draft base, which performs separating, bearing and protective functions.

6. An insulating layer of expanded polystyrene or stone wool.

7. Another waterproofing that protects from getting wet and extends the life of the cake.

8. Reinforced screed with a thickness of at least 5 cm, which performs the main load-bearing functions and serves as the basis for the installation of floor building materials.

The above scheme is the only possible one; pouring a concrete base over the beams is extremely difficult due to its massiveness. The resulting screed can withstand significant loads, including its own weight, the weight of furniture and ceilings, and is suitable for installation of any type of flooring: from self-leveling mixtures to light linoleum. You will find more information about pouring concrete floors.

What to consider during the preparation stage?

The main requirement is the presence of a stable bearing layer; when building on sites with an unsuitable type, the expediency of sampling the soil and replacing it is considered. In other cases, the emphasis is on compaction and alignment. Work begins with markings - a zero level is marked around the entire perimeter of the premises of a private house and a cord is pulled, after which the soil is removed to the desired depth (if necessary, on the contrary, it is poured). Chernozem or soils with a high organic content are recommended to be selected until stable layers are reached, loams and sandy loams are simply leveled. It is difficult to perform high-quality ramming without the right tool yourself, at this stage it is advisable to use a vibrating plate, in its absence, a log with a nailed handle is used.

Sand and gravel are poured in layers (from 10 cm each), ensuring the maximum possible shrinkage. On heaving and frozen soils, the thickness of the first layer is increased to 20 cm, under normal conditions 10-15 cm is enough. Sand is poured with water and compacted every 10 cm, its quality and grain size do not play a special role, but small and dusty varieties are not recommended.

The next layer is filled with dense crushed stone or gravel from a coarse fraction (20-40 mm, from 1000 kg / m 3). Dolomite rocks are not suitable for it because of the low grade strength. By analogy with the sandy layer, this layer is carefully rammed (but without watering). In order to increase the waterproofing properties, it can be impregnated with liquid bitumen, heat-insulating - covered with expanded clay.

The preparation stage is completed by rough concreting - a thin layer of lean mortar with a strength grade within M100. There is no need for its careful smoothing, but air distillation is mandatory. The thickness of the layer in this case depends on the parameters of the soil and the expected loads and varies from 3 to 10 cm; when building on stable and dry soils, it can be replaced by pouring cement laitance over crushed stone; at the risk of frost heaving and significant weight of structures, the feasibility of reinforcing with metal is considered .

The nuances of thermal insulation and reinforcement

Given the high thermal conductivity of concrete surfaces, the presence of an insulating layer between them and the ground is mandatory. Moisture-resistant varieties have suitable characteristics: foamed crumb or foam plastic slabs, stone wool impregnated with hydrophobized compounds, expanded clay or perlite granules. The thickness is determined by the heat engineering calculation, in the middle zone of the Russian Federation, the recommended minimum is 50 mm of extruded polystyrene foam, in the northern latitudes - at least 100. Insulation is placed above the flooring made of polyethylene film or roofing material, with protection on the sides from moisture. The second waterproofing layer is made of similar materials, with a 15-20 cm upward bend and fixation. The stage is completed by placing a damper tape or strips of polystyrene foam around the perimeter of the room and around the supporting columns, if any.

Reinforcing products are placed on top of plastic supports at a distance of 3-5 cm from the upper layer of waterproofing. A metal wire mesh with a cross section of about 3 mm and a mesh spacing of 5×5 has suitable characteristics. It is important to leave the plastic film or membrane intact; wetting of the insulation during the process is unacceptable. Simultaneously with the reinforcement, the installation of beacons is carried out: taking into account the future level and the recommended minimum screed thickness of 5 cm, on mortar or with welding to a fixed element.

As beacons, a T-shaped plaster or ordinary galvanized profile or even rods are used, the placement step depends on the length of the rule (10-15 cm less) and the experience of the installers.

Instructions for concreting

The most important stage is started after setting the composition under the leveling elements. Taking into account the high expected loads, a strength grade of at least M200 is needed, which does not form cracks after solidification. The recommended ratio of binder and filler is 1: 3 (PC M400 or M500 and sand) or 1: 2: 4 (PC, sand, fine crushed stone, respectively), in case of doubt as components or the possibility of observing exact proportions, it is better to use ready-made dry mixes, in particular - sand concrete.

An important requirement is a monolithic screed, with a large amount of work it is extremely difficult to prepare and level the required amount on your own, the forces of at least two people are involved. In any case, the mixture is stirred mechanically (using a concrete mixer or mixer), and not with your own hands. Filling is carried out from a far corner, with simultaneous alignment and compaction of the resulting area. The process is completed by removing the beacons and carefully filling the gaps, then the surface is covered with a film and gains strength within 28 days with constant wetting in the first week.

Ideally, the thickness of each layer justifies the calculation; when choosing a heater, it is mandatory. The use of expanded clay when laying floors requires caution: at the risk of underflooding or constant dampness, it is prone to moisture accumulation and increases the strength of frost heaving. The only problem-free insulation is polystyrene: taking into account the pouring of concrete from all sides, its poor combustibility does not matter, with a minimum thickness of the layer, it effectively retains heat. In case of doubt in the GWL, a drainage system is placed around a private house.

Possible errors and violations of technology include:

• Lack of compensatory materials around the perimeter of the room. Ignoring the laying of the damper tape leads to cracking of the screed during the thermal expansion of concrete.
• Filling at a groundwater level of less than 2 m on the surface, it will not be possible to provide reliable waterproofing in this case, dampness will penetrate inside a private house. The ideal occurrence is 4.5-5 m and below.
• The laying under the leveling beacons of materials subject to decay, this leads to subsidence of concrete floors during operation.
• The laying of an insulating layer below the zero mark in the absence of a heat-insulated base, such an error is fraught with the formation of a freezing zone.

Concrete floors, like any reinforced concrete structure, are a composite building material, which includes concrete stone and steel reinforcing elements. Therefore, the reinforcement of the concrete floor is an integral part of the entire product.

We want to tell you how to properly reinforce reinforced concrete slabs intended for floor structures and foundations.

concrete floors

Varieties

To begin with, it is necessary to determine what types of reinforced concrete slabs exist for covering floor bases, because the method of reinforcing these structures will also depend on this.

So, in construction, the following varieties are used:

• Reinforced industrial floors that can serve as a base for areas with a high load: heavy vehicles, lifts, other mechanisms with a high wheel load on the base surface. Also, such structures are used in factories, warehouses, military facilities and other similar sites;
• Draft slabs, which are poured as the basis of the foundation for the subsequent support of the remaining layers and structures on them. They require high strength and are reinforced with thick reinforcement, made in the form of a frame;
• Concrete floor slabs that are supported only by wall structures and experience severe bending loads that are detrimental to a material as fragile as concrete. Equipped with strong high-section reinforcement, as a rule, in the form of frame formations or several layers;
• Cement-sand screeds, which are produced on an already prepared basis of reinforced concrete slabs. Serve for the final alignment of the base of the floor and the installation of finishing floor coverings. Most often, floor reinforcement is used here with a knitting mesh or road mesh welded by spot welding at the factory. Can be supplied with fiberglass or other polymeric inclusions for greater strength and to prevent cracking of the slab;
• All kinds of self-leveling floors and household screeds for leveling the base for installing floor coverings, as well as for installing underfloor heating. Here, reinforcement is used minimally, since the loads are small, and the base under the slab is strong enough and does not shrink. It is enough to use a road mesh made of wire rod or various reinforcing fibers.

Industrial floors

NOTE! It must be understood that industrial facilities perform serious functions, and any errors and inaccuracies here can cost huge, if not tragic consequences. Building such structures with your own hands is tantamount to building a rover from a Verkhovyna moped, so we won’t tell you how to reinforce a floor for a serious industrial or military purpose, how to build bridges and runways, don’t blame me.

Also, do not forget that the price of such an object will cost about the same as a small revolution somewhere in Eastern Europe, and readers of our articles will be able to march in the parking lot for a start.

Advice! We strongly recommend that you leave the task of reinforcing and building industrial zones and industrial floors, in particular, to serious design and construction companies with impressive funding and a fleet of modern equipment. They sometimes do it a little better, and they know how to write off funds more quickly than our brother.

Floors on the ground

Another controversial type of floor concreting is concreting on the ground. Some argue that reinforcement is inappropriate here, some take the opposite view.

However, everything is not so simple here either:

• the main condition is well-compacted soil;
• and high-quality drainage bedding of gravel and sand.

Then a heat-insulating layer and a vapor barrier are laid, again a mesh, and a finishing screed is poured. As such, you can use a cement-sand mixture or a special floor compound.

Advice! Any reinforcing structures, be it meshes or frames, must lie at a certain (3-5 cm) distance from the floor, otherwise the reinforcement will rust.

Household floors on floor slab

Important! Screeds also require reinforcement. It is only at first glance that concrete or cement is so strong, but at the slightest bend or vibration, it crumbles like autumn leaves. For home screeds and concrete floors, a special steel wire mesh is used, which is called "road".

• After the preparation of the base slab, waterproofing and gluing the damper tape, the floor is insulated with loose or dense slab insulation, which is also waterproofed.
• Then, a reinforcing mesh is laid out on the film or insulation membrane, beacons are set and the screed is formed.

Attention! If the aspect ratio of the room is greater than 8/1, or the room is L-shaped, or has other frilly architectural designs, then you will have to worry about expansion joints.

• To do this, the room is divided into squares or rectangles, into which special profile or other rails are inserted, which are subsequently taken out, and the gap is filled with sealant or a polymer strip capable of leveling the movements of the screed plates.

• After the final installation of the screed, it can be covered with a thin layer of self-leveling floor. Reinforcement of the self-leveling floor of such parameters is not required.

Warm floor

Installation instructions for underfloor heating of various configurations come down to one thing.

• Namely, heating elements of the external coolant supply or electric heaters with a special resistance, which gives a thermal effect when current flows, are mounted in the screed. In any case, a screed is required.
• Since we are talking about reinforcement, we will not go into the intricacies of installing underfloor heating. Suffice it to say that a reinforcing element in the form of a grid is needed there.
• It distributes heat more efficiently, it strengthens the structure, it serves as a simple mount for heating pipes or cables.

The only thing that can be recalled in this situation is that the foundation for the structure must be carefully prepared.

Level differences inherent in floor slabs can simply destabilize our thin screed, and it will burst. Repairs will be expensive.

Again, do not forget about competent waterproofing and do not try to warm up the ceiling of the neighbors from below or the basement, they will not thank you for this. Use thermal insulation, only between the floor and the floor slab (yes, yes, there have been reverse cases).

Also, do not neglect the unimaginable red tape associated with the bureaucratic way of working, the peculiarities of thinking. The water floor in the houses of the old buildings is an object of municipal importance under the protection of UNESCO, since there are very few monuments of such heroism to the residents.

Important! Competent reinforcement of concrete structures, and especially screeds, provided that the recipe for its manufacture is properly maintained, is the key to durability and comfortable operation of the structure as a whole.

The parameters of reinforcement and its spatial arrangement are determined directly for each project and require serious calculations.

Output

As you can see, concrete without reinforcement is not as strong as it seems. The use of steel elements assembled in certain geometric configurations significantly increases the strength of concrete and even allows it to be classified as a new class of building structures. As the video in this article shows the importance of rebar, our experts are unanimous on this issue.

Concreting, done at high speed over large areas, is the most economical way to level an old floor and build a new floor. Once cured, the smooth surface becomes the ideal base for any top coat. To increase the service life of the screed, reinforcement of the concrete floor is used. This process is carried out using various materials and designs from them.

According to their functions and location, the screed is divided into the following types:

• draft - rests on the ground;
• multilayer - includes heat and sound insulating gaskets;
• leveling - is laid on the draft layer, serves as the basis for flooring or tubular insulation;
• construction - lies on the floor slab.

It is advisable to reinforce the self-leveling concrete floor when arranging rough and multi-layer screeds (in the absence of a monolithic support, the effect of tensile and bending loads increases), as well as to reduce the calculated concrete layer.

Types of reinforcing structures and materials

1. Bar frame. Most often, it is laid in two layers, made from rods with a diameter of 6 to 40 mm. Apply with a coating thickness of more than 8 cm.

2. Steel wire mesh. It is used for multi-layer screed on the ground or for hardening the coating in the garage, hallway, kitchen.

3. Polymer mesh. It does not strengthen the screed, but only prevents cracking during the hardening of concrete. It is used for self-leveling floors, reducing the consumption of cement. The grid is installed directly on the base or on the heat-insulating layer.

4. Reinforcing fiber for concrete. There are two types: metal and polypropylene. Polymer fiber gives concrete resistance to cracking during shrinkage, to temperature fluctuations, enhances water-repellent properties.

Metal fiber increases the resistance of concrete to vibrations. Replacing the reinforcing mesh with steel fibers saves time (the elements are introduced directly into the mixer), and reduces the thickness of the screed. Microcracks lose their ability to expand.

5. Combined reinforcement. In addition to the frame mounted in the lower section of the coating, its upper layer is filled with fiber - this is how the concrete floor screed is protected from cracks. The method is applied to the entire surface or in places of increased loads (where the floor is adjacent to walls or columns). Fiber should be dosed according to the instructions.

The main stages of concrete pavement reinforcement

The most time-consuming is the construction of a concrete floor with a soil base. First, according to the technology, a gravel-sand mixture is laid, then a foundation slab, a para-barrier film, thermal and waterproofing. Next, a reinforced concrete layer is mounted.

1. Depending on the thickness of the screed, in private construction it is reinforced with a frame of bars or wire mesh. The diameter of the reinforcement for reinforcement is taken from the range from 8 to 20, and the wire - from 4 to 6 mm. The cell size is maintained from 10 to 20 cm.

2. The frame of solid rods is knitted with a wire with a diameter of 2 - 3 mm, the layers of the frame are attached to the ribs. If scraps of material are used, they are overlapped with a half-meter approach.

The wire mesh is purchased ready-made (cells 5 - 20 cm) or knitted by hand. Purchased products are connected with a wire with an overlap of 1 - 2 cells.

3. The finished structure is laid on the latches ("high chairs") at a level of about 3.5 cm from the base. When pouring, the steel elements must be in the middle of the concrete layer - in this case, the loads are evenly distributed over the surface of the coating, its mechanical resistance is ensured, and there is no metal corrosion.

Consumption of reinforcement for floor reinforcement

Table 1 shows the data for the mesh version of the reinforcement, and in table 2 - for single reinforcement with steel bars from 10 to 16 mm.

The concrete base is considered the most common floor covering. Reinforcement of the concrete floor or its strengthening increases the service life of the base, and also prevents the destruction of concrete.

Many builders, especially beginners, face the question: “How to reinforce a concrete floor?” First of all, you need to figure out what material the reinforcing surface is made of:

• reinforcing bars;
• welded mesh.

It will be extremely useful for you to familiarize yourself with the choice.

Advantages and disadvantages of reinforced concrete floors

Fibre-reinforced concrete is used to reinforce the floor over large areas. The thickness of the screed must be at least 50 - 70 mm. The average area of ​​the premises is 3000 sq.m. Fiber Advantages:

1. Impact resistance.
2. Vibration resistant.
3. Crack resistance.

Such reinforcement of the concrete floor, reviews of which are very diverse, also has its drawbacks - this is the complexity of manufacturing and low bearing capacity.

Without reinforcing bars, it is impossible to imagine the calculation of the bearing load. Most often, bulk or double reinforcement is used for medium and heavy traffic and pedestrian loads.

Important! Before pouring concrete, the reinforcement process can be controlled by yourself, that is, make sure that the diameter and knitting of the reinforcement, cell sizes, etc. are correctly selected.

The disadvantage of this type of reinforcement is the high complexity of the process. You can't do without.

Welded mesh (otherwise called road mesh) is used only for light loads, that is, single reinforcement is used. Experts recommend using it for screeds with a thickness of no more than 70-100 mm for light traffic and pedestrian loads. This method of strengthening concrete is less complicated, moreover, during the pouring of concrete, the process can be controlled.

Payment

Before starting work, it is important to calculate the possible consumption of reinforcement for floor reinforcement . For each method, the calculation will be individual:

1. For single reinforcement 1 sq. m. you will need: AIII fittings (8,10,12,14,16 mm), knitting wire (0.064 mm), compensators (0.6 mm) and clamps (5 pcs).
2. For bulk reinforcement, a reinforcement cage is required - 2.1 kg per 1 sq.m.
3. To work with a road mesh with a thickness of 5-7 mm, you need to purchase a knitting wire (0.0035 mm), a Vr1 mesh (1.1 sq.m.) and a “high chair” type reinforcement retainer (5 pcs).
4. The concentration of steel fibers for concreting: with light load - 20 - 25 kg / m3, with medium - 25 - 40 kg / m3, with heavy - 40 - 80 kg / m3.

Subject to all proportions, you will receive high-quality reinforcement of the concrete floor. Video of the work can be viewed on the Internet.

Basic Rules

Without following certain rules, it is impossible to reinforce the concrete floor. The technology is quite simple, but failure to meet the requirements will lead to the fact that all the work will be done in vain:

• the reinforcing surface should not interfere with the distribution of concrete;
• the material must be evenly distributed over the surface, it is advisable to use props;

Important! Supports should not be used when reinforcing concrete with fiberglass.

• do not contaminate materials with oily substances, they reduce the adhesion of concrete to the reinforcing component;
• so that the base does not rot and oxidize, the concrete must completely cover the reinforcement.

Stages of work

If all structures and materials are prepared, then you can proceed to such a process as reinforcing a concrete floor, the stages of work are as follows:

1. First of all, you need to lay out the material, without which high-quality reinforcement of the concrete floor is impossible. The diameter of the reinforcement must be determined in advance. It is laid out on the construction site at a level of 3-4 cm from the boundaries of the floor covering. To do this, use stands or clamps - "chairs".
2. Before pouring, metal structures must be correctly placed - they must be at the indicated boundaries or in the center.
3. If you use strength enhancers, then they must be added to the concrete in advance and mixed for at least 15 minutes.

Advice! To strengthen concrete, you can use propylene or metal fibers. .

1. Safe shrinkage of the material will be ensured if you work with a road mesh. Distribution fittings are needed to reduce the local impact of the load, mounting fittings - for a stronger bond.

Reinforcement of the concrete floor (consumption of reinforcement , the necessary materials, etc. are described above) is impossible without preparation and calculations. A high-quality concrete floor can be obtained by following the instructions and following certain rules. The optimal ratio of wear resistance, economy and strength is achieved with the right choice of reinforcement method and compliance with the design loads.