An insulated monolithic slab will last for many years without structural damage from exposure to adverse factors.
Laying a shallow slab foundation during the construction of small buildings provides quite significant savings in materials and financial resources. However, seasonal freezing of the soil leads to movement and uneven rise and settlement of the laid slab, resulting in its deformation and subsequent destruction of the entire structure. Insulating the slab foundation by laying horizontal thermal insulation will help to avoid such risks, allowing you to cut off the zone of frost heaving of the soil under the structure.
Monolithic slab foundations find their priority application in the construction of one to three-story houses. It is a rigidly reinforced reinforced concrete structure that allows it to absorb large external loads along the entire load-bearing plane of the slab without deforming it. Since the depth of such a foundation is higher than the level of soil freezing, the forces of frost heaving in the soil have to be compensated by insulating the foundation slab with heat-insulating materials even at the construction stage. The insulation must meet several basic requirements:
Previously used for such work mineral wool does not meet modern construction requirements due to insufficient rigidity of its structure, high water absorption and relatively low thermal insulation qualities. Newest technologies production during manufacturing thermal insulation materials provide a wide range of choices. Depending on the method of insulation of a monolithic foundation slab, the most popular are:
These synthetic polymer foams provide reliable protection the soles of the monolithic slab from freezing. In addition, for shallow foundations, a foundation called an insulated Swedish slab is widely used, which is ideally suited for heaving soils. Help you choose the right insulation for a monolithic foundation short review properties of materials and installation methods.
The main feature of this heat-insulating material is its dense closed cellular structure, filled with inert gases by 85-90% and ensuring its low thermal conductivity. To insulate foundations, the material can be used both in the form of finished sheets and in the form of liquid self-foaming two-component compositions, inflated by spraying.
Application liquid composition polyurethane foam on concrete screed under the foundation slab being prepared compares favorably with the use of similar sheet materials.
In addition, environmental friendliness insulating material allows you to use it to insulate a finished foundation even indoors. But the main disadvantage in using polyurethane foam is high price components of sprayed insulation and the unavailability of special equipment for work at home.
Extruded polystyrene foam is widely used for insulating a monolithic foundation slab due, first of all, to its affordability. Essentially, this is the same foam, but the difference in manufacturing technologies determined their different properties and thermal insulation characteristics.
Main advantage extruded polystyrene foam is that for small specific gravity it has high compressive strength. This property allows it to withstand significant static loads without undergoing deformation, and the porous structure of gas-filled closed cells determines its low thermal conductivity.
An undoubted advantage over polystyrene foam is the ability of extruded polystyrene foam to be minimally saturated with moisture, practically not allowing it to pass through. Polystyrene foam, due to its structure, has high water absorption, which is why it quickly loses its heat-insulating properties and becomes unusable, so its use as insulation for a foundation slab is undesirable.
Extruded polystyrene foam (EPS) is produced in the form of finished sheet material under different trademarks and, accordingly, different thicknesses. To reliably insulate the foundation slab, it is necessary to first make a calculation by determining the required thickness, taking into account the density of a specific grade of EPS, thermal resistance stacked concrete slab, as well as the climatic region. It is better to leave this task to specialists or use the instructions of SNiP on construction heating engineering and thermal protection of buildings.
Calculation of the thickness of thermal insulation materials when insulating a slab foundation is a fundamental factor in the construction quality basis building under construction!
Laying of expanded polystyrene sheets is carried out on waterproofing, which is used as bitumen roll materials. The sheets are glued end-to-end to each other on a preheated required temperature surface. On waterproofing materials, which do not have a bitumen coating, are additionally applied adhesive composition with special mastics. It should be taken into account that they should not contain various types of solvents, otherwise it will not be possible to avoid melting the polystyrene foam sheets.
Some manufacturers produce EPS boards that have lock connection, which simplifies their installation and ensures minimal gaps between them. This insulation design helps reduce heat losses and eliminates the so-called “cold bridges”.
Before pouring a monolithic slab, the laid insulation will need to be protected from contact with the components of the liquid concrete mortar. When reinforcing the foundation with bonded iron frame, it will be enough to use a polyethylene film with a thickness of 150-200 microns, which is laid in one overlapping layer with an overlap of 100-150 mm and secured with double-sided tape. If welding work is required to install the fittings, it is recommended to protect the installed heat-insulating material cement-sand screed or low-quality concrete.
One of the fairly common options for insulating a shallow slab foundation is the method of combining monolithic design building communication systems. Heating, water supply and sewage pipes passing through the slab additionally heat the slab and soil, preventing them from undergoing uneven deformations. Such structures are indispensable on complex heaving soils, as well as on peat bogs with a high moisture content.
To avoid direct contact with the ground, additional insulation of the “Swedish plate” is carried out using extruded polystyrene foam sheets. In this way, the thickness of concrete in the foundation monolith is reduced by almost 2 times.
The technology for constructing a slab foundation using the “insulated Swedish slab” type consists of several stages:
The main advantage of this insulation method is the combination of technological operations for installing a slab foundation with the simultaneous laying of communications, which can significantly reduce construction time. In addition, the ease of erection of the structure does not require the involvement of heavy construction equipment at the site.
Careful adherence to technological standards, as well as rules and methods for insulating shallow monolithic slabs in various climatic zones, allows the construction of foundations for low-rise buildings on almost any soil.
Insulating the slab of any foundation is one of the most important things when building a house. It is best to do this in warm time years, and you can’t do this in rainy weather. Insulation of a monolithic foundation slab is especially important for cold regions where the soil freezes at great depths. When heaving soils freeze, they can increase in volume, which leads to deformations of the entire building. Therefore, it is so important to take care of the external insulation of the foundation. This will help reduce heat loss throughout the entire future building and preserve its durability.
The better all the work is done, the longer and more reliably the building will last. And most importantly, the house will remain warm even in very coldy. Do not forget that most of the cold enters the house through the foundation. And if the building has basement(billiard room, gym), then you should take care of internal insulation. This is especially important if ground floor not heated. But the most important thing is external insulation any residential building.
The main reasons why insulation is necessary:
All this will help not only to always feel comfortable in your home, but will also increase its lifespan.
The most important part of the work when insulation of a fresh foundation slab is required is the selection suitable material. It should not deform under soil pressure and absorb moisture. These are the most important parameters any thermal insulation. These won't fit soft materials like mineral wool. Most the best option– These are polyurethane foam and extruded polystyrene foam. Both of them have excellent thermal insulation characteristics and a fairly low cost, which is also important during construction.
This material is universal, as it combines not only thermal insulation, but also sound and waterproofing properties. To use this type insulation, special equipment will be required, since it must be sprayed. For complete insulation, 50 mm of insulation thickness, laid in several layers, is sufficient. All joints must be sealed after insulation.
This material has a number of positive properties:
And the main thing is that when using polyurethane foam, there is no need to use additional means for steam, water and waterproofing. It has only one drawback - the need to use special equipment. Therefore, this method of insulation will require either considerable investment or the help of experienced specialists with appropriate equipment.
This type of insulation costs significantly less than polyurethane foam and is easier to install. This material consists of plates that do not allow or absorb moisture. It retains its thermal insulation properties for a long time even in cold regions. Advantages of extruded polystyrene foam:
It is most often used when it is necessary to insulate the foundation, since it can be installed independently, without the use of additional equipment.
This new variety insulation. Milling grooves on the surface of polystyrene foam slabs are excellent for insulating the foundation. Used in conjunction with geotextile fabric as fastener drainage. Its main properties:
To insulate a monolithic slab, you can use both polystyrene foam and polyurethane foam. But the first option is preferable. Expanded polystyrene is the most effective and less expensive, and most importantly, it is easy to install. Before proceeding with its installation, it is recommended to lay waterproofing, then you can begin laying extruded polystyrene foam slabs.
Most effective method insulating the foundation with this material means using it in zones of soil freezing. The insulation is installed to the freezing depth. This is quite enough. Special attention when insulating, it is worth paying attention to the corners: in such places, the polystyrene foam used should be thicker than in other areas. It is imperative to insulate the soil around the perimeter of the building. To do this, it is necessary to place insulation under the blind area structure.
All rows of extruded polystyrene foam boards must be laid end-to-end, from bottom to top. Large seams are filled polyurethane foam. This will ensure high tightness, thermal insulation and waterproofing properties. The slabs are placed on polymer glue or mastic, and then pressed with a layer of soil. When insulating, it is important to take into account that all slabs are the same width; you cannot use already used material, this may break the tightness. This method is suitable for all types of foundations, including monolithic ones.
When is insulation done? monolithic foundation When using polyurethane foam, it is important that there are no tears or gaps. The insulation must form a completely closed loop. This will allow you to achieve maximum thermal insulation properties. It is sprayed onto the foundation using special equipment. The material then hardens within 20 seconds. In general, the entire process of installing insulation is quite simple and quick. The application of polyurethane foam is done in several layers, after each of them has dried. One layer should be approximately 15 mm thick.
Upon completion of all work, it is done with soil. Equipment for installing such insulation can be purchased in specialized stores or rented. But it’s easier and faster to use the services of professionals.
Insulation of a monolithic slab updated: February 26, 2018 by: zoomfund
Thermal insulation of a home must begin from the foundation, and the best material This is what polystyrene foam is for. Insulating the foundation with polystyrene foam is a 100% proven option, + the video will help you master the technology. And although this method not the cheapest, but very effective, and also quite simple to implement.
Expanded polystyrene sheets have big amount positive properties:
In addition, this material is easy to install and lasts about 40 years if the thermal insulation is carried out according to all the rules. Have expanded polystyrene and disadvantages:
To attach polystyrene foam sheets, do not use organic solvent glue or hot mastic. To protect the insulation from damage, it must be transported and unloaded carefully, not thrown from a height, and be sure to close it after installation. exterior finishing- tiles, siding, plaster or at least cement mortar.
| Technical characteristics of polystyrene sheets | Index |
|---|---|
| Temperature range of operation of sheets not subject to mechanical loads (C°) | from -18 to +60 |
| Density (kg/m3) | 1040 - 1060 |
| Hardness (MPa) | 120 - 150 |
| Softening temperature (Vic) in air (C°) | 85 |
| Softening temperature (Vic) in a liquid medium (C°) | 70 |
| Tensile strength, MPa (kgf/cm2), not less for sheets with a nominal thickness up to 3.75 mm inclusive | 17,7 (180) |
| Tensile strength, MPa (kgf/cm2), not less for sheets with a nominal thickness of over 3.75 mm | 16,7 (170) |
Insulation
First you need to calculate how many insulation boards will be needed for the foundation. Dimensions standard plate expanded polystyrene – 600x1200 mm, thickness from 20 to 100 mm. For the foundation of a residential building, slabs 50 mm thick are usually used, laid in two layers. To find out how many slabs you will need, total length the foundation is multiplied by its height and divided by 0.72 - the area of one sheet of polystyrene foam.
For example, if a 2 m high foundation is insulated in a 10x8 m house, the thermal insulation area is equal to 72 square meters. Dividing it by 0.72, we get the number of sheets - 100 pieces. Since the insulation will be carried out in two layers, it is necessary to buy 200 slabs 50 mm thick.
This, however, is a very average calculation, based on the fact that the insulation thickness will be exactly 100 mm. But this value can be greater - it all depends on the climatic conditions of the region, the foundation material, and the type of insulation.
There is a special system for calculating thickness, which requires knowing the R index - this is a constant value of the required heat transfer resistance established by SNiP for each region. You can check it with your local architecture department, or take it from the table below:
| City (region) | R - required heat transfer resistance m2×°K/W |
|---|---|
| Moscow | 3.28 |
| Krasnodar | 2.44 |
| Sochi | 1.79 |
| Rostov-on-Don | 2.75 |
| Saint Petersburg | 3.23 |
| Krasnoyarsk | 4.84 |
| Voronezh | 3.12 |
| Yakutsk | 5.28 |
| Irkutsk | 4.05 |
| Volgograd | 2.91 |
| Astrakhan | 2.76 |
| Ekaterinburg | 3.65 |
| Nizhny Novgorod | 3.36 |
| Vladivostok | 3.25 |
| Magadan | 4.33 |
| Chelyabinsk | 3.64 |
| Tver | 3.31 |
| Novosibirsk | 3.93 |
| Samara | 3.33 |
| Permian | 3.64 |
| Ufa | 3.48 |
| Kazan | 3.45 |
| Omsk | 3.82 |
Insulation of a monolithic foundation slab is necessary in areas with cold climatic conditions. Such measures are required in order to protect the base from harmful effects. environment, preservation of warmth, comfort and comfortable conditions living in a house. Some of the most common materials for insulation are polystyrene foam and polyurethane foam.
Thermal insulation of base slabs in this way is a relatively new type of modification of private houses. It began to be used in the 50s - 60s of the XX century. This type of slab insulation is durable and has a long service life. According to statistics, the popularity of expanded polystyrene is growing steadily every day.
Strengthening monolithic slabs with polystyrene foam has proven to be very good decision during the construction of houses, because their service life is more than 50 years. After carrying out various tests and checks, it became clear that the material did not change in any way over the entire period of operation.
It follows from this that the growing popularity and steady increase in consumption of expanded polystyrene is a pattern. Over the past 20 years, its use has increased tenfold. Main consumers of this material are Europe and North America.
Extruded polystyrene foam for insulating a monolithic base slab is a material that has a uniform structure consisting of closed cells. Due to the low density of the material, its thermal insulation properties increase. You should also know that polystyrene foam has increased strength characteristics and can withstand fairly heavy loads.
Expanded polystyrene practically does not allow water to pass through and is not afraid of exposure to chemically aggressive environments. Thermal insulation with this material is made in regions with severe winters and very cold weather. Expanded polystyrene copes well with multiple cycles of freezing and defrosting, while its performance characteristics don't change at all. Expanded polystyrene is usually sold in the form of slabs.
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The foundation wall is covered with spread mastic. Then polystyrene foam is placed against it and pressed tightly. All row slabs are installed in a similar manner.
When carrying out work, you must carefully monitor the connection of adjacent slabs. It should be clear, without gaps and be locked.
The joints on the ridges of the locks at the corners are cut off. If necessary, the joints are additionally filled with polyurethane foam.
As the higher rows are laid, the lower rows are covered with soil. Such actions make the work easier and help press the material.
Plates located below ground level are glued only with mastic.
This is necessary to prevent damage to the waterproofing.
The insulation located above the ground can be further strengthened using dowel-nails (umbrellas). All this can be easily done with your own hands, you just need to be very careful. To attach the base to the walls, holes are drilled using a hammer drill. Umbrellas are fixed in the center and at the junction of adjacent slabs.
Foundations insulated with polystyrene foam are so popular for the following reasons:
From the above it becomes clear that, insulated with polystyrene foam, it will serve for a long time, and the house will be cozy, comfortable and warm. In addition, the material is absolutely safe from an environmental point of view and has a low cost, which clearly tilts the choice in its direction when long-term construction is ahead.
