In construction, the installation of floor slabs should be treated responsibly, especially if you are building on your own, without a project, as we usually do, for example, on our summer cottages. If the project is approved and a team of qualified builders is working, then such questions do not arise.
Often the answer to a question of interest can be found in articles or books on construction intended for a wide range of readers. For example, you can read that the “Minimum distance” at which the slab should rest, colloquially called the “depth of support” of the ends of the floor slabs, should be at least 90-120 mm. These figures can be used as a guide without going deeply into the intricacies construction business.
If you figure out where these values were taken from and how true they are, then, in the words of Ostap Bender: “The laws must be respected.” In construction, as in any industry, there are regulatory documents.
To determine the “depth of support”, it is necessary to take into account not only the length of the floor slab, but also the material of the supporting surface, the brand of the slab (indicated load bearing capacity slabs), as well as requirements for seismic resistance.
Improper installation of a slab on a supporting wall is a violation that will not be overlooked by regulatory authorities. Concerning guidance documents: then there are GOST standards and Series project documentation, which indicate the amount of support.
For example, in series 1.400-11/91 “Recommendations for the use of prefabricated reinforced concrete standard slabs in building coverings industrial enterprises» it is indicated that the length of support for the longitudinal ribs of the slabs, taken during design, must be no less than the following values:
Minimum support length in mm for slabs 6 m long
on steel structures- 70 mm
on reinforced concrete structures- 75 mm
for stone structures - 120 mm
Minimum support length in mm for slabs 12 m long
for steel structures - 90 mm
for reinforced concrete structures - 90 mm
for stone structures - 150 mm
In accordance with GOST 956-91 for floor slabs of any length manufactured by reinforced concrete products in Moscow, the support depth is at brick wall set to 10 mm without taking into account the length of the floor slab itself.
You should pay attention to the brand of the plate and the markings applied. Slab brands consist of alphanumeric groups. For example, according to the territorial catalog of the Moscow region, the brand PK 42.15-8T means: PK - name of the product - floor slab with round voids; 42.15 - dimensions of the product in decimeters - structural length 4180, width - 1490; 8 - for a design load of 800 kgf/m2; T - index for heavy concrete.
Signs of places of support on the slab are applied in accordance with GOST 13015.2 in the middle of each side of the support of the slab.
Thus, the more parameters are taken into account, the more accurately you will determine the minimum support of the floor slab.
When building a house, any developer faces the question of choosing an interfloor floor. The most common three types of floors are wooden, monolithic reinforced concrete and prefabricated reinforced concrete, assembled from flat hollow core slabs. It is about this type of overlap, as the most popular and practical for low-rise construction, will be discussed in this material. From this pro interfloor ceilings in a private house you will learn:
- What is the difference between hollow-core floor slabs (PC) and floor slabs made by formless molding (PB).
- How to lay floors correctly.
- How to avoid installation mistakes.
- How to store floor slabs.
How to choose a hollow core slab
At first glance at hollow-core floors, it may seem that they differ from each other only in length, thickness and width. But specifications hollow core floor slabs are much wider and are described in detail in GOST 9561-91.
Hollow core slab, private house.
Hollow-core interfloor slabs differ from each other in the method of reinforcement. Moreover, reinforcement (depending on the type of slabs) can be performed using prestressed reinforcement or without prestressed reinforcement. More often, floors with prestressed working reinforcement are used.
When choosing floor slabs, you should pay attention to the following: important point, as the permissible number of sides on which they can be supported. . Usually you can only support on two short sides, but some types of slabs allow support on three or four sides.
- PB. Provides support on two sides;
- 1pc. Thickness – 220 mm. The diameter of the round voids is 159 mm. Allows support on two sides only;
- 1PKT. Having similar dimensions, it allows support on three sides;
- 1PKK. Can be leaned on four sides.
Floor slabs also differ in their manufacturing method. There is often a debate about what to prefer – PC or PB.
Andrey164 User FORUMHOUSE
It's time to close ground floor buildings with floor slabs, but I can’t decide what to choose - PC or PB, PB has a better surface finish than PC, but I heard that PB are used only in monolithic frame houses and country houses, and the end of such a slab cannot be loaded with a wall.
Sasha1983 User FORUMHOUSE
The main difference between the plates lies in the technology of their manufacture.
PC (thickness from 160 to 260 mm and typical load-bearing capacity of 800 kg/sq.m.) is cast in formwork. PB brand panels (thickness from 160 mm to 330 mm and typical load-bearing capacity from 800 kg/sq.m) are manufactured using formless continuous casting (this allows for a smoother and flat surface than PC panels). PBs are also called extruder ones.
PB, due to prestress compressed and tensile zones (prestressing reinforcement is done at any length of the slab), less susceptible to cracking than PC. PCs with a length of up to 4.2 meters can be produced without prestressed reinforcement and have a greater free deflection than PB.
At the customer's request, PB can be cut to individual specified sizes (from 1.8 to 9 meters, etc.). They can also be cut lengthwise and into individual longitudinal elements, as well as making an oblique cut at an angle of 30-90 degrees, without losing its load-bearing capacity. This greatly simplifies the layout of such floor slabs on construction site and provides greater freedom to the designer, because the dimensions of the building box and load-bearing walls are not tied to standard sizes PC.
When choosing interfloor slabs For PCs (more than 4.2 meters long), it is important to remember this feature - they are prestressed with special stops at the ends of the slab. If you cut off the end of the PC, the stop (cut off together with the end of the PC and the vertical reinforcement) will not work. Accordingly, the working reinforcement will cling to the concrete only with its side surface. This will significantly reduce the load-bearing capacity of the slab.
Despite the better quality smooth surface, good geometry, lighter weight and high load-bearing capacity, this point should be taken into account when choosing a PB. Hollow holes in the PC (depending on the width of the slab, with a diameter of 114 to 203 mm) make it possible to easily punch a hole in it for sewer riser, with a diameter of 100 mm. While the size of the void hole in the PB is 60 mm. Therefore, to punch a through hole in a PB brand panel (so as not to damage the reinforcement), you should check with the manufacturer in advance on how best to do this.
Floor slabs for a private house: installation features
PB (unlike PC) does not have mounting loops (or you have to pay extra for their installation), which can complicate their loading, unloading and installation.
It is not recommended to use the “folk” method of installing the PB, when the fastening hooks cling to the end of the hollow hole. In this case, there is a high probability that the hook will be torn out of the hole due to the destruction of the end of the slab, or the hook will simply slip off. This will cause the slab to fall. Also, at your own peril and risk, you can use a method in which a crowbar is inserted into the hollow holes of the PB (two crowbars on one side of the slab) and hooks cling to them.
Installation of PB slabs is allowed only with the use of soft chocks or a special traverse.
ProgC User FORUMHOUSE
To pull the joist out from under the slab, when laying it, leave a gap of 2 cm to the adjacent slab. Then we move the already laid slab with a crowbar to the adjacent one.
Max_im User FORUMHOUSE
Personal experience: I laid slabs at my construction site using this method. The gap was left at 3 cm. The slabs were laid on a cement-sand mixture 2 cm thick. The mixture acted as a lubricant, and the slabs were easily moved with a crowbar to the distance I needed.
Also, when installing floor slabs, it is necessary to comply with the calculated values of the minimum depth of support for the slab. The following numbers can be used as a guide:
- brick wall, minimum support depth is 8 cm, maximum support depth is 16 cm;
- reinforced concrete – 7 cm, maximum support depth – 12 cm;
- gas and foam concrete blocks– minimum 10-12 cm, optimal support depth – 15 cm;
- steel structures – 7 cm.
It is not recommended to support the floor slab more than 20 cm, because as the depth of support increases, it begins to “work” like a pinched beam. When laying floor panels on walls built with gas and foam concrete blocks, it is necessary to install a reinforced concrete armored belt, which is described in detail in the article:. Read also our article, which explains in detail. We wish you to successfully apply the acquired knowledge on your construction sites!
Before installing the slabs, it is recommended to seal the ends of the hollow holes. The voids are sealed to prevent water from getting inside the panel. This also increases the strength at the ends of the slabs (this applies to a greater extent to PC than to PB) if load-bearing partitions are supported on them. The voids can be filled by inserting half a brick into them and “filling” the gap with a layer of concrete. Typically, voids are sealed to a depth of at least 12-15 cm.
If water does get inside the slabs, it must be removed. To do this, a hole is drilled in the panel, in the “void,” from below, through which water can flow out. This is especially important to do if the floors have already been laid, and the house went into winter without a roof. In cold weather, water can freeze inside the hollow hole (since there is nowhere for it to flow out) and tear the slab.
Sergey Perm User FORUMHOUSE
I had slabs laid on the floor for a whole year. I specially drilled holes in the “voids” with a hammer drill, and a lot of water flowed out. Each channel must be drilled.
Before laying floor slabs, it is necessary to select a truck crane with the required lifting capacity. It is important to take into account the accessibility of access roads, the maximum possible reach of the boom of the truck crane and the permissible weight of the load. And also calculate the possibility of laying floor panels not from one point, but from both sides of the house.
zumpf User FORUMHOUSE
The surface on which the floor slab is laid must be level and free of debris. Before laying the panel, it is “spread out” cement mixture, so-called mortar “bed”, 2 cm thick. This will ensure its reliable adhesion to the walls or armored belt. Also, before installing the panels and before applying the mortar to the wall, you can lay a reinforcing rod with a diameter of 10-12 mm.
This method will allow you to strictly control the vertical mixing of all slabs when laying them (since the panel will not fall below the rod). The rod will not allow it to completely squeeze out the cement mortar from under itself and lie down “dry”. It is not allowed to install slabs in steps. Depending on the length of the slabs, the discrepancy between the ends should not exceed 8-12 mm.
A serious mistake during installation is covering two spans at once with one slab, i.e. it rests on three walls. Because of this, loads unforeseen by the reinforcement scheme arise in it, and under certain unfavorable circumstances, it may crack.
If such a layout cannot be avoided, to relieve stress, a cut is made with a grinder along the upper surface of the panels, exactly above the middle partition (wall).
Another point that you should pay attention to is how to block a flight of stairs between floor slabs if there is nothing to support them on. In this case, you can run two channels parallel to the slabs, and place one across, along the edge of the opening, tie the reinforcement cage in the form of a mesh with a cell of 20 cm and a rod diameter of 8 mm, etc. Place the formwork and fill the monolithic area. There is no need to tie the channel to the floor slabs. In this case, they rest on two short sides and are not subject to loads from the support unit of the flight of stairs.
How to properly store floor slabs on site
Ideally, if the panels are brought to the site, they should be installed immediately. If for some reason this cannot be done, the question arises: how to properly store them.
To store the slabs, it is necessary to prepare a solid and level area in advance. You can't just put them on the ground. In this case, the lower slab may rest on the ground, and, due to the uneven load, it will break under the weight of the upper slabs.
Products should be stacked in a stack of no more than 8-10 pieces. Moreover, spacers are placed under the bottom row (from timber 200x200 mm, etc.), and all subsequent rows are placed through spacers - a 25 mm thick inch board. The spacers should be located no further than 30-45 cm from the ends of the slabs, and they should be positioned strictly vertically one above the other. This will ensure uniform load redistribution.
, and read about e. The video reveals everything
The ceiling is supported on aerated concrete using special armored belts. Its manufacture is necessary to accept loads from gravity and structural materials of the next floors or roof. What is an armored belt? This is a monolithic reinforced concrete structure that follows the contours of the walls. The armored belt is erected on load-bearing walls, which are built using aerated concrete.
To fill the reinforced belt, formwork for concrete is prepared, which is a structure for creating a mold into which reinforcement is placed for rigidity.
If the slabs are supported on the internal walls of the house, the walls are built in such a way that they rest on the foundation. The reinforced belt on the internal walls under the floor slabs strengthens the structure, as the load is distributed over the entire area of the slab. A structure made of brickwork on aerated concrete, as well as reinforcement, is not considered an armored belt. aerated concrete masonry reinforced mesh.
To support floor slabs, the following requirements apply:
- ceilings and coverings must be installed on anti-seismic belts;
- the connection of the plates and the belt must be made mechanically strong using welding;
- the belt should line up across the entire width of the wall; for external walls of 500 mm, it can be reduced by 100-150 mm;
- To lay the belt, it is necessary to use concrete with a class of at least B15.
Support depth
The support of the floor slab on the wall must be at least 120 mm, and reliable adhesion of the slab to the load-bearing wall must also be ensured.
To fill the reinforced belt, reinforcement is first installed, the quantity and installation location of which is determined using calculations. On average, at least 4 12 mm rods are accepted. If aerated concrete is not insulated, but only plastered, then the belt is not made the entire width of the wall, but less by the thickness of the insulation layer.
The armored belt must be insulated, as it is a bridge of cold. The formation of such a bridge can destroy aerated concrete due to the accumulation of moisture. When reducing the thickness of the armored belt, do not forget about the minimum depth of support of the slabs on the walls.
The depths of support of the slabs on the walls have standardized values:
- when supported along the contour of at least 40 mm;
- when supported on two sides with a span of 4.2 m or less, at least 50 mm;
- when supported on two sides with a span of more than 4.2 m, at least 70 mm.
By maintaining these distances, you can be sure that your home will not collapse.
Purpose of the armored belt
When arranging places for supporting floor slabs, it is necessary to take into account the thermal performance of the walls and the materials from which they are built.
So is an armored belt really necessary to support floor slabs on aerated concrete? Let's try to figure it out.
Firstly, the armored belt increases the resistance of the structure of your house from deformation by loads various kinds. For example, shrinkage of the structure, precipitation of the soil underneath it, temperature changes during the day and changes in the season.
Aerated concrete cannot withstand high loads and is deformed under the influence of external applied forces. To prevent this from happening, armored belts are installed that compensate for the load. The armored belt takes on the entire load, thereby preventing the destruction of the structure. Aerated concrete cannot withstand point loads, so the fastening wooden beams When building a roof it becomes very difficult.
The armored belt provides a way out of the situation. The second name of the armored belt is unloading (due to its ability to evenly distribute the vertical load). Its use allows you to add rigidity to the structure. When steam and moisture move, aerated concrete, as a porous material, can expand, which can lead to movement of the floor slabs.
Taking into account these factors, we can firmly say that an armored belt for supporting the floor slabs of the next floor or roof is simply necessary. Otherwise, with any level deviation, a point load is placed on the aerated concrete, which deforms it and destroys it.
The process of constructing an armored belt is not too labor-intensive and expensive, and it will preserve your home longer.
Making an armored belt
The armored belt is installed around the entire perimeter of the building, and the reinforcement is connected by welding or knitting with special wire.
In order to begin work on the construction of the armored belt, you need to prepare tools and accessories:
- hammer and nails for assembling wood formwork;
- fittings for frame assembly;
- welding machine for welding reinforcement bars at corners and at joints;
- container, bucket, spatula for pouring mortar into the formwork.
They are erected under the floor slab, under the roof to facilitate the installation of the roof. If you plan to build an attic in your house, then its slabs also need to increase the rigidity of the base.
To fill the armored belt, aerated concrete and formwork are prepared. Formwork is a structure for creating a form that will later be poured cement mortar. Formwork units:
- the deck, which is in contact with the concrete, gives shape and quality to the face;
- forests;
- fasteners that support the system in a stationary state at the installation level and connect the individual elements to each other.
To construct an armored belt supporting floor slabs, horizontal formwork is used. The formwork material can be steel (sheet), aluminum, wood (board, plywood, the main condition is low hygroscopicity), plastic. If necessary, formwork materials can be combined.
Lightweight and available material for formwork is wood.
If you don’t have time to prepare the formwork, you can spend money and rent it. Today there are many construction companies who provide such a service.
How to make formwork? The design of the formwork is not very complicated. Use boards 20 mm thick, 200 mm wide - this is optimal sizes. Too large a width can lead to destruction of the formwork as a result of cracks. It is recommended to wet the boards before use. The panels of wooden formwork elements are tightly connected to each other. However, avoid large gaps.
If the gap is up to 3 mm wide, you can get rid of it by generously moistening the boards. The material swells and the gap disappears. With a slot width of wooden elements 3-10 mm it is recommended to use tow; if the gap is more than 10 mm, then it is clogged with slats. The horizontality and verticality of the formwork is controlled using building level. This is necessary for the evenness of pouring the reinforced belt and further placement of the floor slab on the belt. Repeated use wooden shields you can wrap them plastic film, this will also get rid of wide gaps.
The smoother the board used in the manufacture of wooden formwork, the geometrically even the armored belt will be.
Reinforcement is placed in the formwork. The ideal option is to use four rods with a diameter of 12 mm or a ready-made reinforcement cage. Minimum requirements Consider laying two 12 mm rods. The reinforcing bars are connected with a “ladder” in increments of 50-70 mm. At the corners, the reinforcement is connected with steel wire or welding. The ladder is obtained by installing jumpers between two solid rods.
For heavy loads from slabs, a three-dimensional frame structure is used. To ensure that the manufactured frame does not touch the aerated concrete blocks, it is laid on pieces of brick or blocks. Before pouring the solution, the location of the frame is checked by level. Having prepared the solution, fill the armored belt. For the solution, use 3 buckets of sand, 1 bucket of cement and 5 buckets of crushed stone. For ease of work, small crushed stone is used.
If the installation of the armored belt is planned in stages, then the filling is carried out according to the principle of vertical cutting. That is, the frame is completely filled in height up to specific place, then the jumpers are set. The material for the jumpers can be brick or gas block.
Work is suspended. Before further work the material of the jumpers is removed, the frozen filled part is well moistened with water, as this ensures a better connection. Pouring concrete should be carried out without the formation of voids; for this purpose, the surface is leveled with reinforcement.
After 3-4 days, the formwork can be dismantled.
On the received armored belt. In practice, hollow-core slabs made of heavy concrete, cellular concrete, and prefabricated monolithic are used. They are selected based on the span size and load-bearing capacity.
Most often, hollow-core slabs PC and PNO are used, the bearing capacity of which is 800 kgf/sq.m. The advantages of such floor slabs include high strength, manufacturability and complete factory readiness for installation.
The support of the floor slab on the reinforced belt of the aerated block structure should be 250 mm. The usual support is 120 mm.
Armobelt in openings
Creating an armored belt over openings has small features. In this case, the support of the slab will be incomplete, since the ceiling hangs over the void. To support the slab, pillars with lintels in the form of beams are erected.
Pillars can be erected using bricks and blocks. Each pillar is laid out in one and a half bricks.
Reinforced concrete lintels are erected between the pillars. The height of the beams should be 1/20 of the length of the opening. If the distance between the pillars is 2 m, then the height of the beams will be 0.1 m. The width of the beams will be determined by the height from the ratio 0.1 m = 5/7. If the distance between the supports is 2 m, and the height of the beams is 0.1 m, then the width of the reinforced concrete beams is 0.07 m. To fill the beams, use removable formwork from boards.
Reinforced concrete slabs are one of the most common types of floors. They provide high strength and allow you to install a rigid structure in the shortest possible time. Installation of floor slabs is a responsible task that requires certain knowledge in the field of construction. First things first.
Types of floor slabs
Before you start installing horizontal design you need to select a type. Reinforced concrete prefabricated structures are produced in the form of:
- multi-hollow;
- flat (PT);
- tent panels with ribs located along the perimeter;
- with longitudinal ribs.
The most common choice is the use of reinforced concrete hollow-core. They are available in two types, depending on the manufacturing method:
- round hollow (PC);
- continuous molding (CB).
Round hollow core slabs are time-tested products that have been used in construction for several decades. Many have been developed for them regulatory documents and installation rules. Thickness – 220 mm. Products are installed according to serial sizes, which creates inconvenience during individual construction.
The manufacturing technology of these slabs involves the use of reusable molds for pouring, and before manufacturing non-standard products, you will first need to prepare the formwork. Therefore the cost the right size may increase significantly. Typical PC slabs have a length from 2.7 to 9 meters in increments of 0.3 m.
Scheme of reinforced concrete products with dimensions The width of reinforced concrete products can be:
- 1.0 m;
- 1.2 m;
- 1.5 m;
- 1.8 m.
Structures with a width of 1.8 m are purchased extremely rarely, since due to their large weight the installation process in the design position is greatly complicated.
PBs are used in almost the same way as the previous type. But their manufacturing technology allows you to give the product any length. Thickness – 220 mm. The width is the same as the PC series. The disadvantage is little experience in use and poor regulatory documentation.
As additional elements to hollow core slabs Flat PTs are often purchased. They are available in thicknesses of 80 or 120 mm and are smaller in size, allowing them to cover narrow corridors, storage rooms, bathrooms.
Supporting the slabs
The laying of floor slabs is carried out after the preparation of the project or diagram on which the products are laid out. Floor elements must be selected so that they are sufficiently supported on a brick wall or expanded clay concrete blocks and laying without gaps in width.
The minimum support for the PB and PC series depends on their length:
- products up to 4 m long – 70 mm;
- products longer than 4 m – 90 mm.
Visual diagram how to correctly and incorrectly support floor slabs Most often, designers and constructors accept the optimal wall support value as 120 mm. This value guarantees reliability even with small deviations during installation.
It would be correct to pre-position the load-bearing walls of the house at such a distance that it would be easy to lay the slabs. The distance between the walls is calculated as follows: the length of standard slabs minus 240 mm. The PC and PB series must be laid with support on two short sides without intermediate supports. For example, PC 45.15 has a size of 4.48 m, 24 cm is subtracted from it. It turns out that the distance between the walls should be 4.24 m. In this case, the products will lie with the optimal amount of support.
The minimum support of PT series products on the wall is 80 cm. Installation of such reinforced concrete slabs is possible with support points located on all sides.
The support must not interfere with the passage of ventilation ducts. Optimal thickness carrier interior wall made of brick – 380 mm. 120 mm on each side goes under reinforced concrete floors, and in the middle there remains 140 mm - standard width ventilation duct. In this case, it is necessary to lay it as correctly as possible. Shifting the product to the side vent will lead to a decrease in its cross-section and insufficient ventilation of the premises.
Summarizing what was said:
- PC and PB series up to 4 m are supported on both sides by at least 7 cm;
- PC and PB series more than 4 m - not less than 9 cm;
- PT series – at least 8 cm on two, three or four sides.
Slab storage
Product storage schemes different types After the scheme has been developed and the products have been purchased, they need to be placed on the building site for convenient installation in the design position. There are rules for storing materials:
- elements must be laid under a canopy;
- the storage location must be located within the access area of the crane;
- Pads are provided for support points.
Failure to comply with the last rule will result in a break in half. PC, PB and PT products work in such a way that the appearance of intermediate supports or a solid base leads to the appearance of cracks. Laying is done in the following order:
- laid on the ground wooden blocks or boards under the edges of the slab;
- on the boards crane I transfer the ceiling element from the car;
- boards or bars are placed again on the laid slab;
- unload the second slab from the machine;
- repeat points 3 and 4, maximum height storage – 2.5 m.
Masonry requirements
Scheme for calculating floor slabs In order to correctly install floor slabs, you need to ensure that special requirements to a brick wall:
- evenness of the masonry in the place where the floors are laid;
- laying in three rows until overlap reinforcing mesh with a 5 by 5 cm cell made of wire with a diameter of 3-4 mm;
- top row to frets with inside must be tychkovy.
If the slabs are mounted on expanded clay concrete blocks, an additional monolithic belt is installed under the floors. This design will help to evenly distribute the load from heavy floors onto expanded clay concrete blocks with less strength. The construction technology involves pouring a monolithic concrete strip 15-20 cm thick onto the blocks.
Laying floors
To carry out the work, a minimum of three people will be required: one performs the slinging, and two install them in the design position. If the installers and the crane operator cannot see each other, when installing the slab, another worker will be needed to give commands to the crane.
Scheme of laying reinforced concrete products Fastening to the crane hook is carried out with a four-branch sling, the branches of which are secured at the corners of the slab. Two people stand on both sides of the support and control its evenness.
When installing a PC, pinching into the wall is carried out in a rigid way, that is, bricks or blocks are laid on both the top and bottom of the slab. When using PB series floors, it is recommended to use hinged fastening. To do this, the slabs are not pinched from above. Many builders install the PB series in the same way as PCs and buildings stand, but it’s not worth the risk, because the quality of the installation load-bearing structures human life and health depends.
Another important feature of the use of products from the PB series is that it is prohibited to make technological holes in them.
These punches are needed for heating, water supply and sewerage pipes. Again, many builders, even when constructing multi-story buildings, neglect this. The difficulty is that the behavior of this type of floor under load over time has not been fully studied, since there are no objects built quite a long time ago. The ban on punching holes has reasons, but it is rather preventative.
Slab cutting
Sometimes, in order to install a slab, it is necessary to cut it. The technology involves working with a grinder and a disc on concrete. PC and PT slabs cannot be cut to length, since they have reinforced reinforcement in their support zones. If you support such a cut slab, then one edge will be weakened and serious cracks will appear along it. It is possible to cut PB slabs to length, this is due to the peculiarities of the manufacturing method. A timber or board is placed under the cut site, which will make the work easier.
Separation along the length is carried out along the weakened part of the section - the hole. This method is suitable for PC, but is not recommended for PB, since the width of the walls between the holes is too small.
After installation, the holes in the support areas on the walls are filled with lightweight concrete or score mineral wool. This is necessary to provide additional strength in areas where the walls are pinched.
What to do if it was not possible to distribute the products evenly across the width
Sometimes the dimensions of the room do not correspond to the width of the products, in which case all the spaces are combined into one. This space is covered with a monolithic section. Reinforcement occurs with curved meshes. Along their length, they rest on the top of the ceiling and seem to sag in the middle of the monolithic section. For floors, concrete of at least B 25 is used.
Technology prefabricated floor on brick or blocks is quite simple, but requires attention to detail.
Building a house is fraught with many nuances that many novice builders don’t even know about. In particular, one of these “pitfalls” is the floor assembly, which is an entire technology responsible for the durability of the house.
That is why it is necessary to approach the solution of this problem with all responsibility, and at least become familiar with the consequences of negligence.
Introduction to floor assemblies
The assembly of supporting a floor slab on a brick wall is nothing more than the junction of two planes: vertical and horizontal. Many private developers play with this point in different ways, but it doesn’t always work out correctly, much less reliably.
Therefore, to avoid adverse consequences associated with expensive repairs, it is necessary to prepare in advance.
Types of floor materials used
These floors themselves are made of reinforced concrete slabs, the most reliable materials available.
There are just some differences in production process, this is related to the structure type:
- Cellular concrete.
- Prefabricated monolithic– the most popular of all presented.
- Made from heavy concrete. This type applies to many materials, since admixtures of heavy concrete are present in various products.
- Multi-hollow.
All of the above floors brick buildings used in certain conditions, depend on the design of the structure, the load being carried out and the dimensions of the span.
They should be divided into two categories:
- Interfloor ceilings in brick house– used for multi-level houses. They are mounted into a load-bearing wall on a special lining, which ensures reliable fixation of the product. In this case, the depth from which the ceiling will lie on the wall is very important.
- The attic type does not experience such high loads, so it is mounted into the wall without a lining.
For your information! If you decide to build a multi-story brick house with your own hands, you should give your preference to a floor made of prefabricated reinforced concrete slabs. They have not only increased strength, but also enormous load-bearing capacity, and also, so to speak, affordable installation.
Support node - find a solution
In order for the support of floor slabs on brick walls to withstand high loads, little use durable materials, this requires the most subtle approach.
- Firstly, you need to correctly calculate the support unit. Keep in mind that it can only be implemented on a load-bearing wall, but cannot be connected in any way to a partition.
Note! Each product ( construction material) has its own marking, which indicates its certain features: seismic resistance, load-bearing capacity and others. This applies not only reinforced concrete slab, but also bricks used as load-bearing structures. For example, double sand-lime brick M 150 – not the best The best decision for the construction of a multi-storey building.
- Secondly, all calculations and a plan for solving the problem must be checked against GOST 956-91 and additional design documents. Otherwise, you may be denied construction.
For example, check out the markings of PC 42.15-8T slabs, where PC is the floor with round voids, 42.15 is the dimensions of the product in decimeters (length 4180, width 1490). Number 8 – maximum permissible load per slab, which is equal to 800 kgf/m2, and the letter T following 8 is the index of the heavy concrete used for the production of this slab.
There is also a certain standard for how the support of floor slabs on a brick wall should look - from 90 to 120 mm. It is this size that should be maintained, adapting to it.
There are two main points to consider here:
- The reliability of the foundation of the house, which must be designed for high loads. It is necessary to avoid places where the foundation could be weakened, which would lead to uneven shrinkage structure, resulting in curvature of the ceiling.
- The width of the foundation should in no case be less than brickwork. In this case, deformation of the load-bearing walls is inevitable - the load of the ceiling will affect the bricks and weaken the cement mortar.
You also need to focus on the thickness of the slab in relation to the thickness load-bearing wall. And this is provided that high-quality building brick, which complies with standards and GOSTs.
Fixing floor slabs
Anchoring floor slabs in a brick house is used to strengthen the structure, increase strength and reduce the likelihood of material deformation. This method It is extremely difficult to do on your own, so it is better to entrust it to professionals, although the price may be unpleasantly high. The main thing in the construction business is reliability and durability.
One feature to be aware of is that the anchors can be positioned through the slab. However, there is a limit - 3 meters from each other, this is the permissible maximum.
For your information! The anchor is also used to fasten prefabricated reinforced concrete slabs together.
Now you understand what a unit for supporting a floor slab on a brick wall is, what is connected with it and what it affects. That is why you can protect yourself from any unfavorable moments even at the design stage.
Conclusion
It is important not only to lay the slabs correctly, but also to build the foundation, withstand the drying time of the mortar, and lay bricks with a minimum joint thickness, as stated in the instructions. You can do all this yourself, but if you are in doubt, it is better to entrust the work to professionals.
