Laying floor slabs: technical requirements. How to lay floor slabs correctly Technology for laying reinforced concrete floor slabs

electric welding machine;

armature;

concrete mortar;

container for mixing the solution;

jackhammers;

3. scrap;

   four-branch sling;

   mortar shovel;

Required personnel for the installation of plates:

fittermounting plates, senior in the link;

fitter, mont slabs;

rigging worker.

Mounting process

Before starting the installation of floor slabs, the points of support are carefully verified

vertically and horizontally, and the cement mortar is applied to the design mark.

Mount the slabs on a layer of freshly laid cement-sand mortar M100.

The thickness of the layer of plastic solution under the supporting parts must be at least 20 mm.

Hollow-core floor slabs resting on external walls made of

bricks, lay on a leveled, freshly laid layer of TsPS M100 20 mm thick.

2. Dimension of embedding slab in brick walls 90-240mm.

3. All floor slabs must have factory sealed end voids

reinforced concrete liners.

4. A row of masonry under the supporting part of the slabs should be done with a bonder.

5. In the nodes of supporting precast concrete slabs on the walls, you need to install

anchor connections.

6. Fastening with anchors of walls with ceilings should be carried out immediately after the installation of the slabs.

overlappings on the solution and checking the correctness of their position.

7. The distance between the anchors should be no more than 3m, location. brand and details

install anchors in accordance with the project drawings.

8. After installation, the recesses in the plates at the mounting loops must be carefully repaired.

concrete B7.5 according to GOST 26633-91*.

9. The seams between the floor slabs are cleaned and carefully sealed.

Monolithic seams should be made after the installation of the connecting elements

concrete B15 with fine aggregate.

10. To pass vertical communications in multi-hollow decking, it is allowed

drilling holes up to 140mm in places of voids without violating the integrity of the ribs, punching

holes with a percussion tool are not allowed. For holes from 140 to 300mm

it is allowed to drill one of the longitudinal ribs together with the reinforcement.

11. When making holes larger than 300mm, it is necessary to make monolithic sections.

12. When laying out the floor slabs, the extreme longitudinal rib is allowed to start

no more than 25mm into the wall.

13. Be sure to perform bonded meshes under the floor slabs in places

intersections of load-bearing and self-supporting walls.

14. All installation work must be made in accordance with the requirements

SNiP 3.09.01-85 "Production of prefabricated reinforced concrete structures and products",

SNiP 3.03.01-87 "Bearing and enclosing structures", SNiP III-4-80 "Safety in construction", as well as the requirements of the requirements of the series 2.140-1vyp. 1 and the requirements given in the working drawings and in the project for the production of works GOST 23118-99 "Building steel structures".

15. Corrosion protection:

All metal anchors and ties must be protected with a layer of enamel

PF-133 (GOST 926-82*) on a layer of soil GF-020 (GOST 18186-79) or a layer

masonry cement-sand mortar GOST28013-98 * thickness

not less than 20mm;

The surfaces of metal embedded parts must be galvanized;

Anti-corrosion coatings damaged during the production process

must be restored by one of the methods listed above.

16. Anchors and connections after installation and welding should be protected with concrete B15

on fine aggregate 40mm thick.

17. Welding should be carried out with E42A electrodes according to GOST 9467-75, thickness

seams 6 mm, but not more than the thickness of the welded elements.

18. Fence 600mm high along the perimeter of the roof

(total height of the fence with the parapet -900mm).

All fencing elements should be painted 2 times with PF-115 enamel

on the soil layer GF-021.

Ceilings in buildings of various purposes are constructed on metal or wooden beams, by pouring a monolithic reinforced concrete structure and using ready-made concrete slabs. The first technique is rarely used, the second is recommended for industrial and public facilities. Installation of floor slabs is the best option for private and multi-storey residential buildings, which allows you to create fire-resistant and durable structures with high rates of heat and sound insulation.

Floor slabs - which ones to choose for a residential building?

Concrete floor slabs (BPP) are divided into hollow and monolithic. The latter have an increased bearing potential and a huge strength margin. Their disadvantages are low noise insulation index, high thermal conductivity and cost, large mass. For these reasons, such products are rarely used in the construction of residential buildings.

Hollow core slabs are more affordable. They differ:

• high level of sound and heat insulation;
• relatively low weight (when compared with monolithic products);
• excellent indicators of fire safety (fire resistance);
• durability and high mechanical strength.

Such BPPs provide effective load distribution on the supporting (bearing) elements and walls of a residential building. The voids, which may be polygonal, oval or round in shape, run the entire length of the concrete products. This makes it possible to use them for laying various engineering communications, previously laid in corrugated pipes, plastic boxes or special cable channels. Hollow-core products are characterized by a flat surface, due to which the measures for finishing the resulting floors require minimal labor and time costs.

Plates should be selected at the stage of drafting a project for a future building. Products for creating floors have different geometric parameters. Not all factories produce a complete range of concrete slabs. This can make it difficult to choose them for the size of the house and lead to the need for cutting products (and this is a truly complex and time-consuming process). The standard geometric parameters of the BPP are as follows:

• width - 119, 99, 149 cm;
• length - 188–628 cm;
• thickness - 22 cm.

The bearing potential of hollow elements per square area is 750–850 kg. The mass of products is 0.5–1.5 tons.

Floor slabs must have surfaces without visible depressions and bulges. They are not allowed to have serious defects (for example, cracks with a thickness of more than 0.1 mm), traces of grease and rust. In terms of width and thickness, the deviation (maximum possible) of the product from the nominal values ​​\u200b\u200bcannot be more than 5 mm, and in length - 10 mm. Acquired concrete plates must have a quality certificate.

Preparation of reinforced concrete products for installation

If the plates are purchased in advance, they must be placed correctly at the venue construction works. It is allowed to store the BPP on a flat area. Bars of wood must be placed under the products. It is impossible to lay slabs on bare ground. Enough two bars. They are placed from the edges of concrete products at a distance of 0.25–0.4 m. It is not necessary to put linings under the middle of the slabs.

Bars for the lowest product are taken 5–10 cm high. Subsequent linings can be 2.5 cm thick. In this case, the bottom plate will not touch the ground even when the bars are pressed into the ground. The permissible height of the BPP stack is 250 cm. Wooden lining blocks are placed one above the other.

Installation of floor slabs is carried out using a crane. It is necessary to prepare a site for it. The land on it must be well compacted. It is forbidden to put a crane near the house being built if the building has a basement (basement) level. Plate lifting equipment is heavy. The supporting leg of the crane will exert significant pressure on the ground. This often causes the collapse of the wall surfaces of the basement.

If necessary, it is recommended to lay out a platform for special equipment with massive road slabs. Such an operation is performed when working on wet soils, as well as if the house is built in autumn or spring. It makes sense to prepare the site in advance. Then you do not have to pay for a simple crane.

BPP laying technology has several important nuances.The following must be taken into account:

• fitting of the structure is carried out on the lower sides of concrete products;
• plates are mounted without gaps, close to one another;
• the smooth sides of the BPP should look down, and the rough sides should look up;
• reinforced concrete slabs rest strictly on the short sides, and their installation is carried out exclusively on load-bearing walls.

It is necessary to prepare in advance cement, sand and water for mixing the masonry mortar, as well as expanded clay or crushed stone. The latter are used to fill voids in concrete products before their rough cladding.

Leveling walls and other mandatory work

BPPs are mounted on walls with minimal height differences in their upper rows. The permissible discrepancy between the latter is no more than 1 cm. Leveling allows this condition to be met. The scheme of its implementation is simple. A long wooden beam is installed on opposite walls. It is placed on it building level. The accuracy of the horizontal plane is determined.

Similarly, measurements of height differences in the corners of the building are made. The values ​​obtained are written with a marker or chalk directly on the walls. After that, two points are set - the lowest and the highest. Focusing on them, the walls are aligned. It is carried out using sand-cement mixture(3 parts sand, 1 part cement, water), which is laid on a metal mesh.

Walls made of gas silicate, slag and foam concrete blocks are additionally reinforced. To do this, a high (15–25 cm) reinforcing belt is equipped. It is mounted using special U-shaped block products or by installing formwork and pouring it with concrete mortar. The belt is made along all (bearing and non-bearing) walls, along the perimeter of the building.

For the manufacture of formwork, flat boards are used. After pouring the structure with concrete, it is pierced with a piece of reinforcement or with an ordinary construction trowel. This eliminates the risk of air gaps. Then the solution is rammed. It freezes within 3-3.5 weeks.

Before installation in reinforced concrete slabs, all voids are closed. Expanded clay (crushed stone) is used to seal factory holes. You can also place pieces of brick in them, and then fill the remaining gaps with cement mortar. The remaining voids are filled with concrete mix.

Laying plates - procedure

The technology of installation of floor slabs involves the participation of 3-4 people. During construction one-story house two of them lay concrete products, and one (crane operator) clings to the BPP. When building a building with several floors, an additional slinger is required. He gives commands to the crane operator, controlling the process of installing the plates in the right places.

The floor installation scheme is relatively simple. The procedure will be as follows:

• A layer of concrete mortar 2-3 cm thick is applied to the upper rows of walls. The mixture should be made thick. Then the slab will not be able to completely squeeze the concrete out of the seam.
• BPPs are raised in a horizontal position to the required height and placed on load-bearing walls. At the same time, the crane slings remain taut.
• Installers, using crowbars, adjust the position of the plates. If the walls were leveled correctly, all products will lie down without the slightest gaps.

After the laying of the plates is completed, the evenness of the resulting surface is checked using a level. In cases where the height difference between individual products does not exceed 4 mm, the installation is considered to be perfect. If the irregularities are more than 4 mm, reinforced concrete slabs will have to be reinstalled. They are lifted by a crane. A portion of the concrete mixture is added (or removed) to the vacant place. Then the plate returns to its place.

The next step is anchoring the floor. The operation allows you to securely fix the plates. The scheme of its implementation is as follows. Anchor loops are attached to the load-bearing walls, which are then wound up to 0.4–0.5 m at the checkpoint. For high-quality fixation of one plate, two fasteners are enough. They are mounted 90–100 cm from the edge of reinforced concrete products. Between themselves, the floor slabs are connected in the areas of the mounting holes using metal rods. They are pulled as tightly as possible and fixed by welding at 3-5 points.

Seams and eyes after performing the described work are filled with fine gravel. The areas treated by him are covered with a solution of cement (1 part) and sand (3 parts). This operation is preferably carried out immediately after the installation of the plates. Then construction debris will not be able to get into the eyes and seams.

Sealing the seams on the ceiling - how to do it right?

Seams on the ceiling surface between concrete floor slabs are formed due to seasonal soil movements and house shrinkage. It is possible to disguise such defects cement mortar. But after a while the seams will appear again. The best option problem solving - installation of tension or false ceiling. But these structures cannot be installed in houses with a small height. There is only one way out - carrying out complex measures that allow you to seal the seams on the ceiling with high quality and get rid of the gaps between the floor slabs for a long time. The procedure is lengthy but not difficult. The old finish is removed from the ceiling. Problematic seams are embroidered with a perforator. Dust is removed from them (used paint brush and a sponge soaked in water).

Seams of small width (up to 3 cm) are treated with a primer and filled with an elastic material (foamed polyethylene, polystyrene, polystyrene). Installed seal fixed with moisture resistant sealant. Large in width, but not deep seams are filled with mounting foam. Gap before it in without fail moisturized. After hardening, excess foam is cut off with a sharp knife.

The treated seams are sealed with cement (composition marked NC). At the same time, a small depression should remain at the junction of the plates. cement coating is dried. A portion of latex putty is placed in the previously left recess, using two spatulas at once - narrow and wide. Flush to the plates level the mixture. It dries within a day. After that, the seam itself and the areas adjacent to it are processed with a starting putty. On top of it, a masking net or a serpentine tape is mounted.

When the putty composition is completely dry, its surface is cleaned with sandpaper. Then the entire ceiling is treated with the next layer of the starting composition. The coating is again leveled with fine-grained sandpaper. Now you can apply finishing putty, dry the ceiling and paint it in the chosen color.

Ceiling structures must meet the requirements for strength, fire resistance, sound insulation and thermal insulation. All these characteristics are possessed by reinforced concrete slab type. They are used in the construction of industrial, multi-apartment and individual buildings.

They serve as floors, where their lower surface acts as a ceiling, and the upper floor of the upper room. Also, the slabs are laid on garages, sheds and other buildings for household purposes, thus forming a roof. Often they are used as a foundation.

Types of floor slabs

There are 2 types: monolithic floor slabs and hollow ones. The first are distinguished by a large margin of safety and bearing capacity. Among the serious drawbacks are their weight, high thermal conductivity and low soundproofing properties. Such products are often used for the construction of public and industrial buildings.

• Hollow concrete products are used in the construction of private houses due to their cheaper cost and light weight compared to monolithic counterparts. This factor, of course, does not allow one to do without special equipment for PC delivery to the site and installation, but, nevertheless, it makes it possible to significantly reduce the load on load-bearing walls and foundations. And as a result, reduce the cost of their arrangement, using a smaller amount of building material.
• The voids that run along the entire length of the concrete product can be round, oval and polygonal in shape. They can be used when laying communications using cable channels, plastic boxes or corrugated pipes.

Hollow core slabs guarantee:

• good heat and sound insulation qualities;
• fire resistance;
• load distribution on load-bearing walls;
• high mechanical strength;
• durability.

Thanks to the smooth surfaces of the slabs, all further finishing work will take place with not only a minimum investment in leveling the ceiling (floor), but also with less labor costs.

floor slab dimensions

• Floor slabs are produced in lengths from 1880 to 6280 mm in increments of 100 mm.
• The thickness of the floor slab is 220 mm. The standard product width is 990, 1190 or 1490 mm, although you can find plates with other sizes.
• The weight of the floor slab is determined by its dimensions, approximately this indicator varies from 500 to 1500 kg. Concerning bearing capacity units of the product, then on average it is 800 kg per 1 sq.m.

What you need to know before buying a PC

• The presence of traces of rust and grease on the surfaces of the product is not allowed.

• The maximum allowable cracks are 0.1 mm, but their complete absence is better.
• All edges of the plates should have the most even surfaces, without bulges and depressions.
• Permissible deviation from the nominal length - 10 mm, thickness - 5 mm, width - 5 mm.
• The product must have the appropriate quality certificates.

Before you start laying floor slabs, you need to know that:

• the rough side of the plate should be facing up, and the smooth side down;
• fitting of products is carried out on their lower sides;
• Reinforced concrete products should rest on 2 short sides, the long side is not recommended to be placed on the wall;
• you will need components for a sand-cement mortar;
• laying of plates is carried out close to each other without gaps;
• crane services are hourly, so everything necessary is prepared for his arrival so that the work goes without a hitch;
• slabs should rest only on load-bearing walls, the rest of the internal partitions (walls) are erected after the installation of the ceiling;
• for a well-coordinated installation to help the crane, you will need at least 2, and preferably 3 people;

• before rough finishing, the voids of the slabs are filled with crushed stone or expanded clay.

Preparing walls before installing floor slabs

• Bearing walls are leveled. They should be as even as possible in height, the allowable difference is a maximum of 10 mm. You can identify the difference in heights by means of a long beam, which is placed on two opposite walls. A building level is placed on top of the beam, and the longer it is, the more accurate the result.
• Thus, all supports under the floor slabs are checked. It is important to take measurements as often as possible. To do this, a beam or bar is installed in the corners of the building, then moves every 1-1.5 m. The relevant data can be written on the walls with chalk or a marker.
• Next is the highest and lowest point and laid out concrete mix using a cellular metal mesh. Supports erected from foam concrete, slag, gas silicate blocks are necessarily reinforced. This can be done by means of a reinforcing belt with a height of at least 15 cm.
• Armopoyas evenly distributes the load, prevents deformation of the walls and protects the floor slabs from breaking.

• The formwork is assembled from the most even boards in accordance with the values ​​obtained, that is, the edges may have various meanings in height. You can use a special U-shaped profile. The structure is arranged around the entire perimeter of the house box, including non-load-bearing walls, especially if the building is made of lightweight block materials.
• To knead the sand-cement mortar, 1 bucket of cement (M500) and 3 buckets of sand are taken, so much water is needed so that the mixture is neither liquid nor thick. Sand must be sifted to remove pebbles, which will contribute to the destruction of the layer under the weight of the slab.
• After pouring, the solution is pierced with a trowel or piece of reinforcement to prevent the formation of air gaps. Rammer should be given increased attention.

• Before laying floor slabs, voids must be sealed to prevent freezing. If the concrete products have been stored at the construction site for a long time, then it is recommended to drill one or two holes in the areas where the voids pass, through which excess moisture will escape. It should be noted that the holes are sealed with concrete mortar, and during installation, the slab should be facing down.
• Factory voids are filled with expanded clay or large pieces of one and a half bricks are simply inserted, and the remaining gaps are closed with cement mortar. Although in recent times factories produce slabs already with closed voids.
• The mixture in the formwork should dry well, gain strength, this will take at least 3 weeks.

Crane platform

• The soil where the lifting equipment will stand must be compacted. It is impossible to install a crane near a house under construction in the presence of a basement. The supporting "leg" of the special equipment creates a very significant load on the ground, which can lead to the collapse of the basement wall.
• For loose or bulk soils, it is recommended to order a crane with a longer boom. If the work is carried out in spring or autumn, when the soil is saturated with moisture, the platform for the truck crane is laid out with road slabs (used products can be used). Because technology can get bogged down in slush under its own weight.

Slab lining

• It is not recommended to cover two spans with one slab. Such a load under certain circumstances can lead to its cracking. If just such a laying scheme was chosen, then in this case it is recommended to make an incision with a grinder with a diamond disk (to its depth) exactly in the center of the middle wall.
• If a crack nevertheless occurs, then it will go exactly in the direction of the notch, which is quite acceptable.
• Unfortunately, it is not always possible to complete the overlap with whole slabs. Sometimes they have to be lined both in width and in length. Here you need a sledgehammer, a grinder with a diamond disc, a crowbar and muscle strength.

• To facilitate the process, use a beam or board of the appropriate length. Lumber is placed under the slab strictly along the line of the future cut. At some point, the concrete product will break under its own weight.
• First, a grinder is cut on the upper surface of the plate along the marked line. Further, by means of a sledgehammer, blows are applied along the entire length of the concrete goods. Hits should be applied as often as possible. If the cut falls on a hollow hole, then the plate will break pretty quickly.
• When cutting the slab in width, considerable effort will have to be applied. The rebar that comes across is cut off welding machine or cutter. It is not recommended to use a grinder, as the disc may “bite”. But if only this tool is available, then do not cut the metal rod to the end - leave 2-3 mm. Perform the final break with a crowbar or sledgehammer.

By cutting the slab, all possible consequences fall on your shoulders! No manufacturer will give official permission to carry out these works.

• If there are not enough whole slabs for a complete overlap, and the remaining space is small, then the laborious cutting process can be avoided by using the following two methods:
• The last or first slab does not adjoin the wall in length. The formed void between the slab and the supporting wall is laid with bricks or blocks. Cement strainer, performed upon completion of construction, will reliably unite and fasten the masonry with the slab.
• This method is good if the existing concrete panels are laid butt-to-butt, and the remaining distance is distributed between the two supporting walls and filled in as described.

• It should be remembered that if the empty opening is more than 30 cm, then when pouring the screed, reinforcement is performed in this area.
• The plates are mounted close to the walls, and the empty gap remains between the plates themselves. Thick moisture-resistant plywood is attached to the lower surfaces of the reinforced concrete products, reinforcement must be laid with a call to the upper surfaces of the plates.
• Thus, something will turn out in the form of a formwork, which is poured with concrete mortar. After complete drying, the plywood is dismantled, and a general screed is made over the boards.

Installation of floor slabs

• For work you will need a crane and at least 4 people (crane operator, slinger and 2 assistants). A prepared concrete solution with a thickness of not more than 20 mm is laid out on the bearing supports with a reinforcing belt. The plate rises in a horizontal position at the desired height. All actions, namely the movement and direction of the load, are carried out under the guidance of the slinger.

Installers accept the floor slab, adjust the optimal location. Before the slings are removed by means of crowbars, the concrete panel is guided to the installation site with maximum accuracy:

• from the slab to the wall along the long side, a minimum distance of 50 mm is left;
• there should be no gap between the plates;
• the width of the support on each short side of the boards must be at least 150 mm.

Inspection of concrete floor slabs

• • After installation of the ceiling, the evenness of the surfaces of adjacent plates is checked by level. If the height difference is more than 4 mm, then the plates are reinstalled. The concrete products are lifted again by a crane, and, in accordance with the situation, the solution is removed or added.
  • Can't be seized concrete layer diluted with water, the solidified mixture is completely removed, and freshly mixed is applied in its place. As soon as the leveling is completed, they proceed to fixing the plates between themselves and to the load-bearing walls.

Anchoring of reinforced concrete floor slabs

Upon completion of the installation work and after the leveling of the plates has been carried out, they are anchored. If there is a project, then a special scheme should be present in the documents. Otherwise, anchoring is done as follows:

• anchor loops are mounted to the load-bearing walls and go onto the floor slabs by about 40-50 cm. As a rule, two fasteners are enough for the entire length of the panel (they are located a meter from the edge of the slabs). In the same way, one anchor is set in width;

• if the docking of the plates occurs along their short side, then these sections are fixed diagonally using working holes with reinforcement located in them. In their absence, you can use special fasteners with L- and U-shaped forms;
• between themselves, concrete slabs are fastened at the points of the mounting holes. Metal rods must be stretched as much as possible and fixed by welding, at least at three points.
• After that, the eyes and seams between the slabs are filled with fine crushed stone, and then sealed with sand-cement mortar. It is not worth delaying with these works, as construction debris can get into the holes.

Features of the technology of installation of floor slabs

• Hollow core slabs are widely used in the construction of low-rise and individual buildings. Although they are smaller and lighter than their monolithic counterparts, they nevertheless require thickened walls and reinforced foundations. In addition, they will not be able to block buildings that are complex in architecture.
• But, despite these shortcomings, the plates provide a reliable overlap, characterized by a long service life. Their use is justified in cases where the plates become the basis for flooring. roofing material, that is, they act as a flat roof.

When preparing and installing floor slabs, it is important to take into account many technical issues, which means that you need to have certain knowledge and skills. If you are unsure of the calculations, contact a specialized organization where they will draw up a project in accordance with all the requirements of SNiP.

Good day dear readers!

At first glance, it seems that doing floor slab installation very easy, but there are some nuances about which it is better to learn now, so that later there will be less problems.

In this article you will learn:

How to mount reinforced concrete hollow core slabs (PC).

How to properly punch a hatch (manhole) in reinforced concrete round-hollow floor slabs for an attic staircase? WATCH THE VIDEO BELOW.

We hammer rusty correctly. 44D08C

How to block half a meter of void without slabs (cheap and easy)?

What to do if the round-hollow slab is cracked.

How to cut a round hollow slab quickly and easily.

Why can the plate burst.

How to seal the ends of the slabs so that the round-hollow slab does not freeze.

1) A little bit of the necessary theory.

Types of plates with which we most often work:

There are slabs - multi-hollow panels, hipped panels with ribs along the contour in the form of a cornice (one slab lies on the whole room) and ribbed prestressed slabs, the length of which can be from 9 to 15 meters.

Very rarely we use layered solid panels for overlapping.

Monolithic reinforced concrete floors are also rarely used (mainly for non-multiplications), since it is two to three times more expensive than prefabricated multi-hollow floors and several times longer in time.

Slabs can block the floor in one day, and monolithic overlap may be delayed for an indefinite period (set up the formwork, tie the reinforcement, pour concrete, remove the formwork, etc.)

In this article, we will consider the most common and most optimal floor slabs - round-hollow reinforced concrete. The voids in the slabs are of various shapes, oval and irregular in shape:

Hollow core slabs have some advantages over other slabs, namely:

Noise isolation due to voids.

Relatively light weight.

Additional thermal insulation due to voids and so on.

2) How to cut a round hollow slab easily and quickly.

You won’t believe it, but with the help of a crowbar, a grinder and a fist, you can cut a reinforced concrete round-hollow slab across, 1.2 meters wide, in 40 minutes. You will say: “Why do I need to cut a slab, make it smaller in length, if I can order a slab of any length?”.

This is absolutely correct, of course, but this is not always the case. In almost all the houses that we built, we had to cut at least one slab somewhere.

For example, to block a bay window, it is necessary to make a reinforced concrete monolithic ceiling above it or cut a round-hollow slab in the shape of a trapezoid.

The second example is to cut the same hatch in the ceiling so that there is a hole in the attic. Or you just need to reduce the length of the reinforced concrete slab.

Summary: very often you have to cut, cut and chop in some places in the reinforced concrete floor.

a) Cut the plate across.

So we need to make the reinforced concrete slab a little shorter. The slab lies on linings on the ground. On top of the plate we mark with chalk the size we need. From above, the slab mode is a large grinder, a disk on concrete.

Nuance: the chalk mark on the slab must necessarily coincide with the lining under the slab (it will be clearer later).

If, for example, it is necessary to cut off half a meter from a hollow-core slab, then we mark half a meter from the edge, but before that, when unloading the slab on the ground, we put a wooden lining not on the very edge, but also half a meter from the edge

After we cut through the chalk with a grinder, we hit the pipes (voids) near the cut with a fist. It is necessary to hit not on the edge, but in the pipe. With 3 - 4 hits you will break through the pipe. And so we break through all the pipes with a fist.

As the saying goes: “It is better to see once than hear a hundred times and read a thousand times”, so below in the third section (how to make a hatch in a round-hollow reinforced concrete slab) you will see in the video how easily reinforced concrete slabs break through.

Then, when the pipes are pierced, we hit the rib, only not from above, but from the side. By that time, most likely an unnecessary piece of the slab (half a meter) sank under its own weight and made the work even easier.

When the pipes are pierced, the ribs are knocked down with a fist, the crowbar gets down to business. We break through the lower part of the pipe with a crowbar and get to the working fittings. We clean the reinforcement from concrete and cut it with a grinder with a metal disc.

The torn edge of the slab is best “packed” with backing bricks and covered with mortar, this will strengthen it.

b) Cut the slab along.

In principle, cutting a plate along is even easier than across. The only difference is that it takes longer to cut in length, since the slab can be 6 meters long, while only 1.2 m -.1.5 m needs to be cut across.

The principle of cutting a slab along is exactly the same as across. We beat with a fist on the top of the plate along the pipe along the entire length.

To make the edge of the plate more accurate, you can first cut it with a grinder, and then hit the cut with a fist. Then we break through the bottom of the pipe along the entire length with a crowbar.

In the course of cutting the slab, a mesh will come across (smooth reinforcement with a diameter of 3 mm - up to 8 mm), which we also cut with a grinder.

Conclusion:

Plates are cut very easily. When I first cut the slab, I couldn't believe my eyes. It was very easy and I began to doubt the strength of round-hollow slabs.

But this is not so, hollow-core slabs are very durable, they can withstand 800 kg / m2. Strength in hollow-core slabs is ensured by: ribs, reinforcement, the principle of a corpse, and so on.

3) How to make a hatch in a round-hollow reinforced concrete slab.

In this video (see above), we cut through this hatch in about 50 minutes.

Nuance: it is necessary to cut the reinforcement with a grinder carefully, since the reinforcement is tense and it can pinch the disk in the grinder. Best of all, just cut the rebar with a grinder, and then hit this cut with a crowbar or fist.

The safest way is to cut the reinforcement in the hatch with an autogenous cutter.

So that the contours of the hatch are not much smoother, you can cut it first with a grinder around the perimeter (top). In the video above, we cut a manhole across the pipes in the slab.

The dimensions of the hatch for the attic stairs.

Hatches for stairs are usually punched between two plates, at the junction. The width and length of the hatch depends on:

Floor slab widths.

The loads that the cut plates will experience. For example, roof racks will be supported on these cut plates (the roof will be crushed).

If the pits are wide, then the hatch can be made larger. In the video above, the width of reinforced concrete round-hollow slabs is large 1.5 meters.

Often we make manholes 900 mm by 900 mm in slabs 1.2 meters wide. That is, we cut 450 mm in one plate and 450 mm in another plate. These are the dimensions of the hatch for ladders but they are not very comfortable. Since the stairs for the attic will always be stored somewhere nearby, in the living room.

It is best to use folding attic stairs, which are attached to the hatch cover and fold when the hatch is closed.

The most common dimensions for folding attic stairs: 600 mm by 1200 mm; 700 mm by 1200 mm; 600 mm at 1300; 700 mm by 1300 mm; 700 mm by 1400 mm.

For example, if you chose a folding attic ladder measuring 700 mm by 1400 mm, then it is very IMPORTANT to cut the hatch in the slabs in such a way that the long side of the hatch (1400 mm) was along the slabs, not across.

4) How easy it is to cover half a meter of void without slabs.

We use this method when it is not possible to cover all non-folds with plates. When it is not possible to purchase plates different widths. When you do not want to cut floor slabs along.

a) The best and easiest way.

When installing reinforced concrete slabs, sometimes there are no multiplicity. That is, it is not possible to completely cover the entire space of the house, holes remain. Below we will consider how you can block half a meter without plates.

So, for example, we block the first floor of the house with round-hollow slabs. When laying out the slabs, we do not have enough half a meter to completely cover the floor.

When we mount the first slab, we retreat 250 mm from the edge of the inner wall. Next, we mount the remaining plates.

Between the last plate and inner wall 250 mm is also missing. In other words, we divided our half a meter of not multiplicity in half by 250 mm and made them on both sides (holes between the wall and the slab 250 mm each).

The cinder block will not fall, as it rests with its butt (poke) against the slab.

Nuance: cinder block is best built with holes in the side, so that there are no holes from below or above.

If you are already very worried about strength, then you can strengthen this place (where the cinder block is placed) when you are doing the floor screed. To do this, it is necessary to put a masonry mesh on top of the loose cinder block or tie a mesh of reinforcement with a diameter of 6 mm.

b) The second method is more laborious.

You can also disperse the plates, that is, make small equal distances between them.

For example, to block a floor, 10 slabs are needed and a hole of 500 mm (half a meter) remains. We mount the first slab from the edge of the inner wall (so that there is no gap). We mount the second plate with a small indent from the first 55 mm.

Ten plates are nine joints between them. We divide 500 mm into 9 joints, we get 55 mm distance between the plates.

5) Why can a round-hollow slab burst.

Very often, when mounting floor slabs, a broken slab comes across. This happens most often from improper storage of floor slabs or transportation.

In the photo below you can see how under no circumstances should round-hollow floor slabs be stored.

All these plates burst, and the lower ones in several places. I took a closer photo

Many times I saw how the slabs seemed to be stacked correctly, but the winter passed, the base under the slabs became sour, the middle of the slab touched the ground and the slab burst.

To prevent the slab from bursting, it is necessary to carefully consider the stacking of slabs. To do this, it is necessary to make a good base under the edges of the first plate (lower).

It is desirable that the plates lie on the horizon. It is important that the first pads under the slabs are high in case it starts to sink into the ground.

In no case should the middle of the slab touch the ground, since it is almost 100% that it will burst and not just one, but also those that are on top of it the same!

The next spacers between the slabs are usually made from wooden slats. Here you need to pay attention to three factors:

a) That the slats are of sufficient thickness so that the plates do not touch each other.

b) So that the wooden slats (pads) are one above the other VERTICALLY.

c) Gaskets are laid from the edge of the slab by 200 - 400 mm.

The height of a stack of slabs on a good, solid base can reach a maximum of 2.5 meters (8 - 10 rows).

6) What to do if the plate is cracked.

If the cracks on the round-hollow slab are not very large, then in principle there is nothing to worry about. Cracked slabs were installed on almost every house we cost.

Below we will consider the options for where it is best to mount cracked plates so that a minimum load presses on them:

a) If the crack on the slab is large, then we usually put such a slab on the main (or outer) wall by 100 - 150 millimeters.

In other words, we mount the cracked slab so that it rests on three walls, namely the ends of the slab rest on the main walls and the long side of the slab also comes in and rests on the main wall.

From above, the cracked slab is pressed higher standing walls and you get a pretty solid cover.

b) You can also mount a cracked slab, where a brick partition will stand under it. In other words, the cracked slab will be supported from below by a partition.

in) We mount the cracked slab between good, whole slabs. We draw attention to the fact that the rusts between the cracked slab and the good one are well sealed. When the solution in the locks hardens, the overlap will be solid.

G) If you don't really like the quality of hollow-core floor slabs (cracks), you can strengthen the screed over these slabs. The screed can be made concrete, with reinforcement. It will turn out a reinforced concrete screed that will completely unload and strengthen the floor slabs.

e) It is possible to mount cracked slabs in those places where the minimum load will press on them. For example, mount a cracked slab to the very top - attic floor, where crushing will not press or lean on it (stand and the like).

e) If the slab is severely cracked, forming a gap of 4-10 mm, then it is best to cut off such a slab and make it short.

7) How to score rusty correctly.

Rusty- these are the joints of the plates. Two plates are mounted side by side, to each other with a long side. Between them is rust:

Rusty should always be hammered with mortar. Why hammer rusty? The fact is that round-hollow slabs have locks on the sides, round recessed dimples photo below:

When these recesses are filled with mortar, the plates interlock with each other and the overlapped becomes one. Thanks to the locks, the plates are rigidly linked to each other.

How to fix defective rust.

Sometimes you come across defective round-hollow slabs, with irregular sides (where there are locks). When installing such slabs, the rust turns upside down, that is, the top of the slabs fits snugly against each other, but the bottom does not.

Seal up inverted rust is very easy. To do this, we mount the plates with a small run-up of 20 - 30 mm from each other. In other words, so that the top of the plates (along the length) does not fit tightly, but has a gap of 20 - 30 m.

Then from below, under this inverted rustication, we tie up the board for the entire length of the plates and fill the rustication with mortar from above. The solution should not be completely liquid, but not thick either.

Due to the fact that we have a small gap between the plates on top (20 - 30 mm), it is easy to pour the solution into the rust through it.

8) Installation of reinforced concrete round-hollow slabs.

It is very important to observe safety precautions when installing plates!

Most often we mount the plates with a truck crane. We move the plates (correct) to the desired position with a crowbar. Due to the fact that the plates are mounted on the solution, they easily move within 10 - 20 minutes.

It is desirable to support the plates on the wall by 120 - 150 mm.

In order not to constantly run after the mortar during the installation of the plates, we mount the first plate and put a trough with mortar on it with a crane. With the remaining solution in the trough, we hammer the rusts between the plates.

9) We seal the ends of the plates so that the plate does not freeze.

a) The slabs rest on the outer wall.

When resting the end of the slab on the outer walls, it must be sealed to retain heat.

The ends of the plates can be sealed (packed) in several ways:

shoved mineral wool into the pipes of the slab, to a depth of 200 - 300 mm.

Insert concrete plugs or pour lightweight concrete, depth 120 - 250 mm.

Insert a backing brick on the mortar into the pipe and cover it well with mortar. It is best to insert a one-and-a-half backing brick into the pipe.

It happens that the end of the slab comes too close to the front brick. If there is no insulation between the front masonry and the slab and the ends of the saw are not “packed”, then the slab may freeze.

Summary: we seal the ends of the slabs most often with backing bricks.

What to do if the plate is frozen?

It was in our practice: we mounted one plate close to facing brick and did not close the end of the plate. The stove froze and the house was covered with ice. The owner of the house turned on the heating and the stove began to “cry”.

In other words, the house is warm, and frost entered the voids of the slab, the temperature difference caused a dew point and the slab was constantly wet.

The way out of this situation is very simple - we drill with a puncher all the frozen pipes in the slab from below, near the outer wall. We insert a tube into the hole, directing it to the outer wall and blow a little mounting foam into the pipe.

That is, we blow out the pipes in the slab with mounting foam near the end, which rests on outer wall. We blow out a little foam, approximately, to get a cork of 100 - 200 mm.

b) The slabs rest on the inner wall.

According to the requirements in construction, the ends of the slabs are sealed, which rest on the inner wall from the third floor and below.

For example, a two-story house, we have three floors:

Basement covered with tiles.

The first floor is covered with a slab.

The second floor is covered with slabs.

It is necessary to close up the ends of the slabs that are mounted on the basement so that the voids of the slab do not collapse from a higher standing load.

The ends of hollow-core slabs that cover the first and second floors do not need to be sealed. We usually close up all the ends of the slabs, on all floors.

You can fill the ends of the slabs with concrete or lay one and a half bricks:

It is most convenient to seal the voids in the slabs in advance, before installation, on the ground.

Conclusion.

For myself I would do:

I would block my house with reinforced concrete round-hollow slabs.

I would cut the slab for the bay window in the shape of a trapezoid.

For an attic staircase, I would cut an opening 700 by 1300 mm.

If there were not enough slabs to cover the floor (about 500 mm), I would let in a block.

Cracked slabs would be thrown on the wall.

I would qualitatively close up all the rusts.

Do-it-yourself installation of floor slabs.

Currently, in our country, the most popular are three methods of building floors in the house. This is the installation of floor slabs, the device of a monolithic reinforced concrete floor and the device of flooring on wooden (less often metal) beams. We will definitely talk about all these methods and not only. And the first technology that we will consider is the installation of finished floor slabs.

First, a little about the floor slabs themselves. Depending on their shape, all plates can be divided into flat and ribbed. Flat, in turn, are divided into solid and hollow. We are now interested in void ones, because it is this type of slabs that is used mainly in low-rise construction.

Hollow core slabs, in turn, are also classified according to various parameters, such as the shape and size of the voids, the thickness of the slabs, the manufacturing technology of the slabs, and the method of reinforcement.

I will not delve into the topic of classification. It is better to look for this information on the websites of enterprises producing reinforced concrete products (reinforced concrete products). We'd better talk directly about the installation.

The very first point that you need to pay attention to even at the design stage of your future home is the opportunity to purchase in your area exactly the slabs of the sizes that are laid down in the project. Each manufacturer has its own specific range of manufactured products and it is always limited. This is really important and it surprises me that very often developers forget about this recommendation and then they have to either cut one or more slabs or make a monolithic section on the floor. We'll talk more about this below.

Storage of floor slabs at the construction site.

Of course, it's great if you have the opportunity to lay floor slabs immediately upon delivery, directly from the machine that brought them. But most of the time this doesn't happen. Or the driver insists that you unload the plates as quickly as possible, because. he is in a hurry for the next order, or the plates are not laid on the machine in the order you need, or you just bought them in advance and are not going to lay them yet. In all these cases, the plates will need to be stored on your site.

Try to choose for this flat surface. Never lay tiles directly on the ground. Be sure to put something under the edges of the plate, for example, trim wooden beam. There should be only two linings, at a distance of about 25-40 cm from the edges. Linings cannot be placed under the middle of the plate.

Boards can be stacked up to 2.5 meters high. Make the linings under the first slab higher so that in the event of their possible indentation into the ground when laying subsequent slabs, the first one in no case touches the ground, otherwise it can easily break. It is enough to make all subsequent linings even from an inch (2.5 cm). They must be stacked strictly on top of each other.

Preparation for installation of floor slabs.

Preparation begins even at the moment when the masons kick out the last rows of masonry. The slabs will lie flat and without drops if the upper rows of load-bearing walls are even and lie in the same horizontal plane.

To achieve this, there must be horizontal level marks in all corners of the overlapped room. They are put in the process of building walls using a level, either a laser level, or a hydro level. And when the last row of masonry is done, the distance from the marks to the top of the walls is controlled with a tape measure. It should be the same in all corners. From my own experience, I can tell you for sure that some masons neglect this, especially when they make backing masonry at the same time as the front one, performed “under the bar”.

Top row brickwork load-bearing walls should be bonded. That is, if you look from inside the overlapped room, then only poking should be visible on the load-bearing walls (on which the floor slabs rest) in the uppermost row of masonry.

If the slabs are placed on a load-bearing partition 1.5 bricks thick (i.e., the slabs rest on it on both sides), then the top row of such a partition is laid out in one of two ways:

Before laying floor slabs on walls from various blocks (foam concrete, gas silicate, slag, etc.), it is necessary to make a reinforced concrete belt (usually about 15-20 cm thick). Such a belt is made either by pouring concrete into the formwork, or using special U-shaped blocks around the entire perimeter of the house box, i.e. not only on load-bearing walls, but also on non-bearing ones.

When installing hollow core slabs, the holes in them must be sealed. It is much more convenient to do this in advance, while the plates are still on the ground. In general, SNiP prescribes to fill voids without fail on the side of the slab that rests on the outer wall (to reduce the likelihood of freezing of the slab), and on the side that rests on the internal partition, only starting from the third floor from the top of the house and below (to increase strength). That is, if, for example, the house has a basement floor, a floor between the 1st and 2nd floor and an attic floor over the 2nd floor, then it is mandatory to close the voids from the side of the load-bearing partitions only in the basement floor.

I will say that when laying the slabs, we always close up the holes. Moreover, in recent years, more and more hollow-core slabs come from factories with holes already sealed. It's comfortable. If the holes are not sealed, we insert a one-and-a-half brick (maybe even a half) into them and pass the remaining gaps with mortar.

Also, before installing the plates, it is necessary to prepare a site for the crane in advance. Well, if in the place where the crane will stand, the soil is, as they say, native, caked. Worse, when the ground is bulk. If you have a basement, you can not put the tap too close to the house, in order to avoid what is shown in the figure below:

In such cases, it is better to order a truck crane with a longer boom. Also, sometimes in the place where the crane will stand, you first have to put several road slabs (usually there are used ones somewhere). Often this has to be done in the fall in rainy and slushy weather, when the site is so “broken” that the crane simply gets stuck on it.

Three people are enough for the installation of floor slabs. One clings to the slabs, two lay. If desired, you can cope with two, although not always. It happens that when overlapping, for example, the second floor, the installers and the crane operator do not see each other. Then at the top, in addition to 2 people directly laying the slab, there should be another person who will give commands to the crane operator.

Laying starts from the wall on a mortar layer of no more than 2 cm. The mortar must be thick enough so that the slab does not squeeze it completely out of the seam. After the crane operator places the slab on the walls, he first leaves the lines taut. At the same time, with the help of a crowbar, the plate, if necessary, is not difficult to move a little. If the upper surfaces of the load-bearing walls were made even, then the slabs will lie flat, without drops, as they say "from the first approach."

Regarding the size of the support of the plates on the walls, I will give an extract from the document “Manual for the design of residential buildings. Issue. 3 (to SNiP 2.08.01-85) 6. FLOORS ":

Paragraph 6.16.: The depth of support of prefabricated slabs on the walls, depending on the nature of their support, is recommended to be taken at least, mm: when supported along the contour, as well as on two long and one short sides - 40; when supported on two sides and a span of slabs of 4.2 m or less, as well as on two short and one long sides - 50; when supported on two sides and the span of plates is more than 4.2 m - 70.

When assigning the depth of support for floor slabs, the requirements of SNiP 2.03.01-84 for anchoring reinforcement on supports should also be taken into account.

In our practice, we try to support at least 12 cm, since now it is possible to purchase exactly the plates that are needed. The step of their lengths is 10 cm.

I often hear disputes about whether hollow core slabs can be supported on three sides (two short and one long) and how long it is possible to put the slab on the wall with the long side. From what is written above, it follows that it is possible to support the plates in this way. But it is not so. If you read the indicated SNiP, then it says that slabs that rely on three sides have a different reinforcement scheme than those that rely on only two sides.

The vast majority of hollow core slabs, which are now produced by reinforced concrete factories, are designed specifically to rest on two short sides, so it is not recommended to start them with the long side on the wall. Under a certain load, this can lead to cracking of the plate. The reinforcement scheme and, therefore, the possibility of supporting the slab on a third side must be clarified with the manufacturer.

Also, an error associated with improper loading of the slab is the overlapping of two spans at once (see the figure below):

Under certain unfavorable conditions, the slab can crack, and the place where the crack appears is absolutely unpredictable. If you still use such a scheme, make a cut with a grinder (to the depth of the disk) on the upper surface of the plate strictly above the middle partition. Thus, in which case the crack will pass exactly along this section, which, in principle, is no longer scary.

Of course, it’s good if we manage to overlap only with whole slabs. But the circumstances are different, and yet sometimes some plate (or even more than one) has to be cut along or across. To do this, you will need a grinder with a diamond blade for concrete, a sledgehammer, a crowbar, and not the most frail man at a construction site.

To facilitate the work, it is better to lay the stove on a lining. Moreover, this lining is placed exactly under the cut line. AT a certain moment, the plate will simply break along this line from its own weight.

First of all, we make a cut on the upper surface of the plate with a grinder along the cut line. Then, striking with a sledgehammer from above, we cut a strip along the top of the slab. It is quite easy to break through concrete in the void area. Next, we break through the lower part of the plate with a crowbar (also along the voids). When cutting the slab along (we always chop along the hole in the slab), it breaks rather quickly. When chopping across, if the slab is not broken after destruction by a crowbar, a sledgehammer strikes from the side on vertical partitions plates to the victorious.

In the process of cutting, we cut the falling reinforcement. It is possible with a grinder, but it is safer by welding or a gas cutter, especially when the reinforcement in the slab is pre-stressed. A disk from a grinder can bite. To prevent this from happening, do not cut the reinforcement to the end, leave a couple of millimeters and then break it with a blow from the same sledgehammer.

Several times in our practice, we had to cut the slabs along. But we have never used, let's say, "stumps" with a width of less than 60 cm (less than 3 holes remain), and I do not advise you. In general, when making a decision to cut a slab, you take full responsibility for the possible consequences, because not a single manufacturer will officially tell you that it is possible to cut a slab.

Let's now see what can be done if, nevertheless, a whole number of plates is not enough for you to completely cover the room:

Method 1- we put the first or last (maybe both) plates without bringing the long side to the wall. We lay the remaining gap with bricks or blocks, hanging them no more than half from the wall (see Fig.):

Method 2- we make the so-called "monolithic section". From below, plywood formwork is placed under the slabs, a reinforcing cage is made (see the figure below) and the area between the slabs is poured with concrete.

Anchoring of floor slabs.

After all the plates are laid, they are anchored. In general, if the construction of a house is carried out according to the project, then an anchoring scheme must be present in it. When there is no project, we usually use the circuit shown in the figure:

The anchor is made by bending the end into a loop that clings to the mounting loop of the plate. Before welding the anchors to each other and to the mounting loops, they must be pulled as far as possible.

After anchoring, we immediately seal with mortar all the mounting eyes in the slabs and rustication (seams between the slabs). Try not to delay this so that construction debris does not get into the rusts, and water does not pour into the eyes during rain and snow. If you suspect that water has got into the slabs (for example, you bought slabs with voids already sealed, and rainwater could get even during storage at the factory), it is better to release it. To do this, after laying, simply drill a small hole in the slabs from below with a perforator, into those voids where the mounting eyes are located.

Especially dangerous is the presence of water in voids in winter time when the house is not yet heated (or not completed at all) and the slabs freeze below zero. Water saturates the bottom layer of concrete, and with repeated freeze-thaw cycles, the slab simply begins to collapse.

Another way of fixing the plates is the construction of the so-called concrete ring anchor. This is a kind of the same monolithic reinforced belt, only it is not made under the slabs, but in the same plane with them, also around the entire perimeter of the house. More often this method is used on houses made of aerated concrete, foam concrete and other blocks.

I must say right away that we have never used it because of the much greater laboriousness. I think the ring anchor is justified in more seismic regions than our Nizhny Novgorod region.

Do-it-yourself installation of floor slabs, MAIN