Is it necessary to insulate the ends of the floor slabs? Insulation of interfloor ceilings. Technical characteristics of PIR boards PirroUniversal
Floor slabs
Factory-made floor slabs are a very popular option for floors in individual housing construction, because... the alternative is a monolithic concrete floor - a much more labor-intensive thing, difficult for inexperienced private developers. Unlike a monolith, slabs come with a factory-guaranteed maximum load, which is more than enough in a private home.
Description
There are two GOST standards for floor slabs in Russia:- GOST 9561-91 “Reinforced concrete hollow-core floor slabs for buildings and structures. Technical conditions."
- GOST 26434-85 “Reinforced concrete floor slabs for residential buildings. Types and basic parameters."
- 1PC - 220 mm thick with round voids with a diameter of 159 mm, designed for support on two sides;
- 1PKT - the same, for support on three sides;
- 1PKK - the same, for support on four sides;
- 2PK - 220 mm thick with round voids with a diameter of 140 mm, designed for support on two sides;
- 2PKT - the same, for support on three sides;
- 2PKK - the same, for support on four sides;
- 3PK - 220 mm thick with round voids with a diameter of 127 mm, designed for support on two sides;
- 3PKT - the same, for support on three sides;
- 3PKK - the same, for support on four sides;
- 4PK - 260 mm thick with round voids with a diameter of 159 mm and cutouts in the upper zone along the contour, intended for support on both sides;
- 5PK - 260 mm thick with round voids with a diameter of 180 mm, designed for support on two sides;
- 6PK - 300 mm thick with round voids with a diameter of 203 mm, designed for support on two sides;
- 7PK - 160 mm thick with round voids with a diameter of 114 mm, designed for support on two sides;
- PG - 260 mm thick with pear-shaped voids, designed for support on two sides;
- PB - 220 mm thick, manufactured by continuous molding on long stands and designed to be supported on two sides.
This list does not include PNO type floor slabs, which are found in reinforced concrete manufacturers. In general, as far as I understand, slab manufacturers are not required to comply with GOST (Government Decree No. 982 of December 1, 2009), although many produce and label slabs in accordance with GOST.
Manufacturers produce slabs different sizes, you can almost always find the size you need.
In most cases, floor slabs are made prestressed (clause 1.2.7 of GOST 9561-91). Those. the reinforcement in the slabs is tensioned (thermally or mechanically), and after the concrete has hardened, it is released back. The compression forces are transferred to the concrete, and the slab becomes stronger.
Manufacturers can strengthen the ends of the slabs that are involved in the support: fill round voids with concrete or narrow them in this place cross section voids. If they are not filled by the manufacturer and the house turns out to be heavy (the load on the walls at the ends increases accordingly), then the voids in the area of the ends can be filled with concrete yourself.
The slabs usually have special hinges on the outside, by which they are lifted by a crane. Sometimes reinforcement loops are located inside the slab in open cavities located closer to the four corners.
Floor slabs in accordance with paragraph 1.2.13 of GOST 9561-91 are designated as: type of slab - length and width in decimeters - design load on the slab in kilopascals (kilogram-force per square meter). The reinforcement steel class and other characteristics may also be indicated.
Manufacturers do not bother with designating the types of slabs and in price lists they usually write only the type of slab PC or PB (without any 1PK, 2PK, etc.). For example, the designation “PK 54-15-8” means a 1PK slab with a length of 5.4 m and a width of 1.5 m and with a maximum permissible distributed load of approximately 800 kg/m2 (8 kilopascals = 815.77 kilogram-force/m2 ).
Floor slabs have a bottom (ceiling) and top (floor) side.
According to paragraph 4.3 of GOST 9561-91, slabs can be stored in a stack no more than 2.5 m high. Pads for the bottom row of slabs and gaskets between them in a stack should be located near the mounting loops.
Supporting the slabs
Floor slabs have a support zone. According to paragraph 6.16 of the “Manual for the design of residential buildings Vol. 3 (to SNiP 2.08.01-85)":The depth of support of prefabricated slabs on walls, depending on the nature of their support, is recommended to be no less than, mm: when supported along the contour, as well as two long and one short sides - 40; when supported on two sides and the span of slabs is 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 the slabs is more than 4.2 m - 70.
The slabs also have a series of working drawings, for example, “series 1.241-1, issue 22”. These series also indicate the minimum support depth (it may vary). In general, the minimum depth of support for the slab must be checked with the manufacturer.
But there are questions regarding the maximum depth of support for the slabs. IN different sources given completely different meanings, somewhere it is written that 16 cm, somewhere 22 or 25. One friend on Youtube assures that the maximum is 30 cm. Psychologically, it seems to a person that the deeper the slab is pushed into the wall, the more reliable it will be. However, there is definitely a limitation on the maximum depth, because if the slab goes too deep into the wall, then bending loads “work” differently for it. The deeper the slab goes into the wall, the lower the permissible stresses from loads on the supporting ends of the slab usually become. Therefore, it is better to find out the maximum support value from the manufacturer.
Likewise, slabs cannot be supported outside of the support zones. Example: on one side the slab lies correctly, and on the other side it hangs, resting on the middle load-bearing wall. Below I have drawn it:
If the wall is built from "weak" wall materials like aerated concrete or foam concrete, then you will need to build an armored belt to remove the load from the edge of the wall and distribute it over the entire area of the wall blocks. For warm ceramics, an armored belt is also desirable, although instead of it you can lay several rows of ordinary durable solid brick, which does not have similar problems with support. With the help of an armored belt, you can also ensure that the slabs together form a flat plane, so there is no need for expensive ceiling plaster.
Laying slabs
The slabs are placed on the wall/reinforced belt on a cement-sand mortar with a thickness of 1-2 cm, no more. Quote from SP 70.13330.2012 (updated edition of SNiP 3.03.01-87) “Load-bearing and enclosing structures”, paragraph 6.4.4:Floor slabs must be laid on a layer of mortar no more than 20 mm thick, aligning the surfaces of adjacent slabs along the seam on the ceiling side.
Those. the slabs are leveled to create a level ceiling, and an uneven floor can then be leveled with a screed.
During installation, the slabs are placed only on those sides that are intended for support. In most cases, these are only two sides (for PB and 1PK slabs), so you cannot “pinch” the third side, which is not intended for support, with the wall. Otherwise, the slab clamped on the third side will not correctly absorb the loads from above, and cracks may form.
The laying of floor slabs must be done before the construction of interior partitions; the slabs should not initially rest on them. Those. first you need to let the slab “sag”, and only then build non-load-bearing interior walls (partitions).
The gap between the plates (the distance between the sides) may vary. They can be laid closely, or with a gap of 1-5 cm. The gap space between the floor slabs is then sealed with mortar. Usually the gap width is obtained “by itself” when calculating required quantity slabs, their size and distance to be covered.
After installation, floor slabs can be tied together using, for example, welding. This is done in earthquake-prone regions (Ekaterinburg, Sochi, etc.); in ordinary regions this is not necessary.
In places where it is difficult to select a floor slab or where it is impossible to install it correctly, a monolithic floor should be poured. It must be poured after installing the factory slabs in order to correctly set the thickness of the monolith. You need to make sure the installation is tight monolithic ceiling, especially if a ladder will rest on it. The space formed between the floor slabs does not always have a trapezoidal shape or a shape with slab protrusions on which you can rest. If the monolith turns out to be rectangular and is not supported by the beveled edges of the adjacent slabs, then it can simply fall out.
Insulation
The ends of floor slabs lying on external walls must be insulated, because reinforced concrete has high thermal conductivity and the slab in this place becomes a cold bridge. Extruded polystyrene foam can be used as insulation. I drew an example:
The load-bearing external wall, 50 cm thick, includes a slab with a support of 12 cm, which is insulated at the end with EPS ( Orange color) 5 cm thick.
Monolithic floors reinforced concrete slabs floors have long been known and have proven themselves in the construction of private and multi-storey buildings. To this day, they are in demand and popular, especially in the construction of cottages. large area. Reinforced concrete hollow-core floor slabs have a lot of advantages; the design of these slabs is such that, in addition to evenly distributing the load over the entire surface, they also additionally add rigidity and stability to the building.
General information and advantages of reinforced concrete slabs
The slabs are made of concrete, in which iron reinforcement is installed during pouring. The slabs have longitudinal voids along their length round shape, which in combination with reinforcement gives the structure a huge advantage. A reinforced concrete slab can withstand bending and not break when high loads, it is very durable correct operation during construction. Monolithic slabs factory-produced meet all the requirements for floors, they are durable and resistant to high temperatures. It is very important that the reinforced concrete slab is a good sound insulator and, in addition, retains heat.
Equally important is the fact that the use of slabs in construction greatly speeds up and simplifies the process; they can be installed where no other flooring method is suitable. For example, laying the floors of a private house with an area of more than 100 m² using pouring will take a lot of time, in addition, labor costs, as well as financial costs, will be much higher than when laying the floor with reinforced concrete slabs.
Correct selection of slabs and calculations
When laying the floor of the first floor, you need to understand that a large load will be placed on it, so it is important to correctly calculate the weight of the structure and take into account everything, including total weight home and furniture or equipment that will be installed on the premises. The thickness of reinforced concrete slabs is standard and equal to 220 mm, but the slabs can be designed for different weight loads depending on their brand. Here, the reinforcement of the slab and what grade of concrete it is made of play a role.
Reinforced concrete slabs are produced in lengths of 2.4-6.8 meters, the width of such slabs, depending on the length, is 1.2-1.5 meters, and their weight is 0.9-2.5 tons. This allows the use of small equipment during construction, cranes with a lifting capacity of up to 3 tons. It is not difficult to understand which slab you need; a marking is placed on the surface, for example, a PC 8-42-12 slab will be 4.2 meters long, 1.2 m wide, with a weight load of 800 kg/m².
Rules for installing slabs depending on the floor
When laying floor slabs, it is important to consider where they will be laid, since installation rules ground floor differ from laying floors between floors.
In the case of laying a basement floor, it is necessary to first carry out work to level the foundation, namely its upper edge. To do this, the upper edge of the foundation is not made of high formwork from boards; here it is necessary to pour a small layer of concrete to create a perfectly flat horizontal surface. Now a reinforced concrete slab can be laid on such a platform.
The slabs are laid taking into account their taper; it turns out that the lower part of the slab will fit smoothly with the adjacent row. There is a small seam at the top that needs to be sealed. cement mortar. This results in an almost flat floor surface in the shortest possible time. Depending on the type of floor you'll be laying, you may need to use a thin screed, but for most flooring materials, a slab without additional finishing is suitable.
In the case when a reinforced concrete slab is laid as a floor between floors, an additional reinforced concrete belt must be made on the walls made of bricks or blocks. This is something like a seismic belt, which is performed as follows. When the height of the walls is laid out to the required height, another row is laid, but one layer needs to be laid in order to leave an inner end around the entire perimeter, into which the slab will lie, and from the outside this place will be covered with brick. Before laying the slab, as in the first case, it is necessary to perform formwork and pour a thin layer of concrete with reinforcement. As a result, a niche is formed with a small gap for laying insulation materials, where the slab is laid. A thin layer of reinforced concrete increases the strength of the surface and evenly distributes the load from the slab along the walls.
Insulation
Floor slabs themselves serve good insulation, since they are located inside the premises of the house, there is no need to insulate them, however, it is necessary to insulate the ends. The stove has high thermal conductivity, which is undoubtedly good, because the stove top floor conducts heat from below and thus the floor becomes warm. But the stove will receive cold from the ends, so you need to protect it with a layer of insulation. In the niche that was formed during the reinforcement process, where the slab adjoins the wall, it is necessary to lay insulation. Then this space, like the rest of the cracks, is filled with concrete.
It is necessary to carry out insulation, otherwise condensation will form in these voids, which the slab will absorb and gradually collapse. In addition to the destruction of the slab, humidity will appear in the room, and in places where there is reinforcement, rust will appear, which will not be covered with any putty.
Actually this is the process of creating floors and interfloor ceilings finished, now you can start finishing the floor with materials. As already mentioned, you may have to apply a thin leveling layer of screed
With these types of work it can help you significantly construction equipment, For example
17.08.2016
Regardless of the purpose of the building, the most important moment during construction is to create comfortable conditions. This depends, first of all, on humidity and temperature conditions. You can achieve the optimal level for both with the help of properly installed and insulated floor slabs.
Features of insulation
Standard technical characteristics of slabs are often not enough to achieve the desired indicators - additional measures have to be resorted to. We are talking about insulating walls and load-bearing slabs.
The process of insulating slabs
When working with floors that are above basements, you should start from the floor. First, a cement screed is laid on top of the reinforced concrete slabs - it is used as a base. In some cases, they do without it, simply sealing the seams between the slabs.
An important element are wooden logs, which are mounted on thin chipboard or fiberboard pads. The thickness of the gaskets is usually about 25 mm.
Logs are also used for insulation - material is placed in the space between them to prevent the penetration of cold and heat loss. Most often, mineral wool, Izol series products, various dry backfills and soft basalt slabs are used for this. The next layer is used to prevent steam penetration. It could be roll material a certain type - from glassine to ordinary roofing felt.
Insulation is required not only for horizontal surfaces, but also for the vertical parts of the slabs - for example, their ends. It is these elements that are most exposed to frost during the cold season.
To prevent a negative effect, construction waste is used (you can fill the brick fragments remaining after construction into the holes in the ends). The holes are then filled with solvent. The space between the end and the masonry is also filled with insulating material, the role of which can be played by mineral wool, basalt insulation and polystyrene foam.
Working with attic floors
Those located in the upper part of the building also need to be insulated, and similar materials are used for this. However, there are also differences. So, thermal insulation should be laid as the first layer on the slabs. It is important to determine the appropriate layer of material - it is calculated based on the climatic characteristics of the region in which construction is carried out.
If you use soft insulating components, be sure to consider that external loads will gradually lead to compression of the material, which means it will lose its ability to protect against heat loss. The loads can be any - even walking to control the condition of the roof causes Negative consequences. Be sure to equip top part buildings with bridges along which a specialist inspecting the roof can move.
To increase reliability, you can perform additional insulation from the inside. Excellent results can be achieved by laying a thin layer of insulation under the hanging ceiling structures. When working, be sure to leave a gap between the insulating layer and the wood flooring to allow fresh air to penetrate.
Floor slabs are reinforced concrete products that are produced for the construction of various structures. They are made of crushed stone and concrete using powerful reinforcement.
The floors are made of crushed stone and concrete using powerful reinforcement.
Laying floor slabs, like any technology, has its own characteristics and rules that need to be paid attention to.
It is important to familiarize yourself with the main stages of work in advance in order to avoid mistakes during the construction process.
In private construction, floors made of reinforced concrete round-hollow slabs are most often used. They are popular due to their advantages, which distinguish them from other types of flooring. Thanks to the voids that are filled with air, they retain heat well and increase sound insulation. Unlike some other similar products, they have significantly less weight, which reduces the load on supporting structures.
Necessary tools for work: trowel, hammer, tape measure.
To carry out the work you will need the appropriate tools and equipment:
- truck crane or tower crane;
- loop grip;
- steel solution box;
- construction steel scrap;
- electrode holder;
- Bulgarian;
- shovels: mortar and collating;
- trowel;
- cam, crowbar;
- steel wire brush;
- hammer and chisel;
- - bucket;
- roulette, level.
The following materials will be needed:
- floors;
- cement-sand mortar;
- electrodes;
- expanded polystyrene.
Diagram of a hollow core slab.
Hollow-core slabs are produced to order in any size, but sometimes situations arise during the installation process when you need to reduce their width or length, or cut out the desired shape. In this case, the slab must be cut using a grinder and a crowbar.
There are two cutting options: lengthwise and crosswise. In order to cut the material crosswise, the following scheme is used:
- the ceiling is located horizontally with linings laid under it;
- the necessary markings for shortening are applied;
- the structure is cut with a grinder along the marked lines;
- using a cam, blows are made on the voids near the cut line across the entire width;
- the bottom wall of the pipe is broken through with a crowbar, and the fittings underneath are cut with a grinder installed disk on metal.
Approximately the same pattern is used to cut lengthwise. But this will take more time, since the length is greater than the width. The stages of work will be as follows:
- it is necessary to mark a line and make a longitudinal cut along it with a grinder;
- use your fist to break the wall of the void that runs along the slab;
- Use a crowbar to break through the bottom wall of the pipe.
During cutting, rods are encountered in the concrete layer reinforcing mesh, which can also be cut with a grinder.
Laying with insufficient width
Floor slab installation diagram.
During the process of laying slabs, it may turn out that the dimensions of the room do not correspond to their dimensions. As a result, gaps appear between the floor elements or between them and the wall. Exists simple circuit fix this problem.
The size of the gap must be divided into two equal parts. In this case, the first slab is laid at a certain distance from the wall, which is equal to the width of one of the resulting parts. All other structures are mounted end-to-end. As a result, a gap forms between the slab and the last wall, where it is necessary to poke a cinder block. It is securely fixed, as it rests against the slab. You need to lay the cinder block so that its holes point to the sides, and not down or up. External wall the structure will further secure it. This design may not seem reliable at first glance, but in reality it is quite durable.
There is another technology for bridging the gap, when its size is distributed between the plates. Then, under each gap, a board is tied, which acts as formwork, into which reinforcement is laid and concrete is poured.
Cracked structure
Sometimes during construction it is discovered that the floor slab has cracked before it has even been laid. The cause of such a defect is improper storage or transportation. The construction material must be stored in a certain way, observing basic rules.
Structural elements must be stacked without touching the ground. Under the lower one, you need to place a non-wetting and non-rotting base, high enough and strong enough. It is advisable to lay the slabs in a horizontal position and install gaskets between them from wooden slats. The distance from the slats to the edge of the product should be 20-40 cm.
If all the necessary conditions are met, if there is a solid base, the stack can have 8-10 rows, but should not have a height of more than 2.5 meters.
Laying a broken slab
If the slab does crack, can it be used as a floor? Builders quite often use flooring materials with similar defects during construction; they are laid provided that the cracks are not too large. At the same time, it is important not to load them too much and to secure them additionally.
There are several options where it is better to install slabs with cracks.
- Place it on the outer or load-bearing wall by 0.1-0.15 m. This laying scheme assumes that the slab will rest simultaneously on three walls not only with its short edges, but also with its long side. It is securely pressed against the higher walls, thereby providing additional support.
- You can lay the slab where a brick partition is installed, which will support it.
- There is another installation scheme, when the burst material is mounted between two whole ones. During installation, rusts form between the structures, which must be carefully sealed with mortar to create an almost monolithic ceiling.
- The deformed slab can be laid in a place where there is minimal load. For example, for attic floor, but it is important that structural elements the roofs did not rest on it.
- If the cracks are quite large, about 4-10 mm or there are many of them, it is necessary to cut off the damaged part and use only the whole one.
Sealing joints
A joint or rustle is where the long sides meet. To obtain a strong and solid ceiling, all rustications must be filled with mortar.
Round-hollow flooring materials have locks on the sides, which look like round recesses. During the process of pouring rustications, the recesses are filled with concrete and the slabs are securely connected to each other. Sometimes you come across defective products that have incorrectly made sides with locks. When they are connected, the notch is at the bottom, and the top is tightly joined. As a result, it seems that it will be difficult to fill such rust with concrete. In fact, the scheme of work is quite simple. To repair defective rust, it is necessary to connect the ceiling elements not end-to-end, but to leave a small gap - 2-3 cm. It should be located in the upper part. At the bottom, along the length of the rust, you need to tie wooden board , which will serve as formwork for pouring concrete. The solution, which is not thick in consistency, is poured into the rust through top clearance
. After the solution has hardened, the work can be considered completed.
Installation technology
Diagram of a prefabricated floor slab.
The slabs are laid and lifted by a truck crane. A device is attached to its main hook, which has four cables of equal length with hooks that are connected to mounting loops located on the ceilings. This scheme prevents rotation during lifting and ensures a horizontal position for the product. The technology involves laying the material on a solution that will prevent the formation of cracks and promote a strong fit of the building elements. Therefore, within 10-20 minutes it is allowed to move them using a crowbar to give the desired position. The slabs must rest on load-bearing walls
and approach them by about 0.12-0.15 m.
A steel rod is inserted into the mounting loops, which are located nearby, and its protruding edges are bent inward, after which they are connected using welding. As a result, adjacent slabs are firmly connected. It is important that the flooring is laid in the most comfortable conditions. For example, you can place a bowl with a solution on the first installed structure
The laying scheme after completion of their installation provides for sealing the ends to prevent freezing. These actions will help to additionally preserve heat in the house, since the cold will not be able to get inside.
Sealing the ends
There are several ways to seal the ends of slabs.
- You can use mineral wool and fill the voids of the pipes with it approximately 0.2-0.3 m deep.
- Fill voids to 0.12-0.25 m with light concrete mortar or close with concrete plugs.
- To fill the voids, use backfill bricks on mortar and seal the surface with mortar.
Sometimes the slab is very close to the facing masonry. If there is no insulation between them and the ends are not sealed, the ceiling will begin to freeze and become covered with ice in the room. The stove will become a source of cold, and when the heating is turned on, due to a sharp temperature difference, “dew” will form on its surface. To get rid of this problem already finished house, the following scheme of actions will do.
- It is necessary to drill a hole in the frozen pipes from the bottom side of the slab using a hammer drill.
- Insert a tube slanted to the side into the resulting recess. outer wall and blow foam through it.
- The result should be a foam plug extending to a depth of 01.-0.2 m, which will serve as a heat insulator.
The ends must be sealed not only for slabs resting on external walls, but also for those resting on internal ones.
When constructing any buildings, and especially housing, it is important to create the maximum level of comfort in the premises. Indicators of this level are humidity and temperature regime. Protection from cold external air and moisture penetration is provided by enclosing structures (walls, ceilings).
Only the technical characteristics of the construction material itself for reliable protection not enough. Therefore, insulating the floor slab is as important as insulating the walls. For floors above basements, insulation is provided in the floor structure. The first layer is laid over reinforced concrete slabs cement strainer, which serves as a base, but often only seal the seams between the slabs.
Wooden logs are installed on slabs on thin soundproofing pads made of fiberboard or chipboard about 25 mm thick. The space between the joists is filled with insulation. The most common are mineral wool, soft basalt slabs, ready-made dry fillings, materials from the Izol series. Next, a vapor barrier layer must be laid (any rolled material such as roofing felt, glassine, etc.).
In addition to laying insulation according to horizontal surface Insulation of the ends of the floor slabs is also required to prevent them from freezing in winter period. To do this, the holes in the ends are first clogged with construction waste (for example, brick fragments) and filled with mortar. The space between the masonry and the end of the slab, approximately 50 mm, is filled with insulation (mineral wool, polystyrene foam, basalt insulation).
We insulate attic floors
To insulate the attic floor slabs, the same materials are used as for the slabs above the basement. But vapor barrier materials laid in the first layer on the slabs. The thickness of the insulation is determined by calculation taking into account the climatic zone of construction.
When choosing soft insulation, it should be taken into account that under any load it will compress, gradually losing its heat-protective properties. These loads, at least temporary, from walking on the ceiling to inspect the roof, and especially when storing some things in the attic, are inevitable. Therefore, it is necessary to provide areas with walking bridges along wooden joists or areas with dense flooring also made along logs.
If you plan to purchase PB or PC floor slabs for the attic floor, then insulation of the ends of the floor slabs is carried out in a similar way to the method already described.
At repair work additional insulation of attic floor slabs can be done by inner surface from the residential side. Good effect laying a thin insulating layer under hanging structure ceiling.
When insulating the floor slab using any materials under wooden floors on joists or attic walking bridges, you should leave ventilation gap between insulation and wooden flooring.
