The height of the foundation above ground level snip. Foundation height - standard parameters, basic ratios and recommendations of professionals (95 photos). What are the functions of the foundation of the building

The plinth is the outer wall of the foundation, on which the facade rests. At the same time, this is the upper part of the basement walls, if it exists. The height of the basement depends on the type of foundation, the overall design of the house, the nature of the soil, and the purpose of the basement. There are certain building regulations in this regard.

Some homeowners believe that if there is no basement, then the basement is useless, you can make the foundation flush with the ground.

house design without basement

This is mistake. The main task of the base is to isolate the facade from contact with the ground. And so that soil water does not rise from the ground along the concrete in a capillary way, a layer of roofing material is laid between the facade and basement walls.

Base scheme

The plinth must be high enough, regardless of the materials of the facade: wood, foam and cinder concrete, bricks equally suffer from water.

In addition to protecting the walls of the house from destruction, the plinth also solves other problems:

• protects the facade from pollution (due to the proximity of the earth, the lower part of the house suffers from them the most);
• protects the cladding from mechanical damage (basement cladding is orders of magnitude stronger than facade cladding);
• compensates for shrinkage due to the load from the house;
• isolates the basement ceiling (most often wooden) from harmful influences;
• increases the thermal insulation characteristics of the basement;
• gives the appearance of the house aesthetic completeness.
• provides its full ventilation (air vents are usually located in the basement of the foundation);

When designing a basement, one should take into account the climate (average temperature in cold weather), the average annual rainfall. You can determine the minimum basement height for your site empirically: measure the depth of the snow cover for several winters and add 10 cm of margin to the average value.

note

The minimum height of the base above the ground according to SNiP for the southern regions is 20 cm (preferably 30-40). If the house is wooden, the distance from the ground is preferably from 50 to 90. If there is a basement, the recommended basement height can reach 2 meters.

A high plinth is more expensive than a low plinth due to the increase in the amount of work on concreting. But in the calculations, savings are in second place, in the first place are strength and performance, which largely depend on the material of the facade.

The height of the plinth is also affected by its position relative to the facade wall. There are three options:

• sinking - the plane of the base is recessed inward relative to the facade. It is possible only if the thickness of the facade wall is large enough;

• flush with the facade;

• speaker. This option is the only one possible if the thickness of the facade walls is small, and also if the project provides for a basement.

The advantages of the third option are increased thermal insulation characteristics (a necessary property when installing an operated basement). In all other cases, the first option is preferable: the overhanging facade wall reliably protects the base from atmospheric factors and mechanical damage. Obviously, the height of the sinking base should be minimal, because. as it increases, the degree of protection decreases.

Foundation options for the height of the basement in a private house

There are design differences for plinths on low foundations (strip, pile-strip, slab) and elevated (pile, column). In the first case, there are no air gaps between the ground and the floor of the first floor, the internal space is completely closed with a concrete or brick strip - either the upper part of the strip foundation, or a superstructure along the perimeter of the slab. In the second case, a gap remains between the ground and the ceiling, the height of which is determined by the height of the above-ground part of the pillars or piles.

basement at the house with a pile foundation

The choice of the type of foundation depends on the characteristics of the soil, topography, and the mass of the building. This issue is resolved at the design stage of the house.

With a low foundation, the basement can be monolithic or prefabricated - from blocks, bricks. The second option involves less protection of the base from harmful factors.

brick basement scheme on a strip foundation

Greater attention is being paid exterior finish, not so much for aesthetic as for protective reasons. In any case, a blind area is performed (at least to divert atmospheric water from the base), and with a high occurrence of groundwater, a drainage system. Max Height such a plinth is limited mainly by economic considerations.

The pile foundation can be low (the grillage lies directly on the ground) or elevated. Columnar, usually elevated. Since it is considered the most unstable, the height must be at least 20 centimeters (to compensate for heaving of the soil). To ensure sufficient thermal insulation of the internal space of the house, the gaps between the pillars / piles are laid with bricks, covered with asbestos-cement slabs or wooden / plywood panels.

an example of basement insulation and piping of a pile-screw foundation

example of internal insulation of the basement of a pile foundation

example of basement insulation outside the pile foundation

example of finishing the plinth of a pile foundation

The maximum height of such a plinth is structurally limited: the above-ground bearing part cannot be too high.

What is the best basement height?

All of the above does not depend on the presence of an operated basement. The basement floor is an important decision in terms of rational space planning in the house and on the site. Suitable for solving almost any task: if desired, you can equip here not only a cellar or a boiler room, but also a study, a home theater, a bedroom. Even taking into account the additional costs of the foundation, a large basement height for a one-story house will be cheaper than building a second floor.

note

The total height of the basement (according to SNiP) is at least 2.5 meters. More.

Characteristics of the floor according to the standards:

• ceiling height relative to ground level - within two meters;
• deepening the basement floor into the ground - no more than half the height of the basement.

The height of the basement floor of your house will also depend on the purpose of the basement. If you are planning to make a bedroom or a room for a comfortable stay, it is better to be guided by the maximum value; when arranging a utility compartment at ceiling height, you can save (within reasonable limits).

• Tags: basement height snip basement ground floor

The basement is the lower part of the outer wall of the building, which is erected on the base and plays the role of a barrier between the wall and the destructive effects of atmospheric phenomena. A building without a basement is at risk from mold and rot and is less able to retain heat inside during the cold season. The main condition for a brick base on a strip foundation is high strength. Its structure must withstand the entire mass of the walls of the building. High-quality materials with a high level of resistance to frost, moisture and pressure strength will help to achieve the required indicator.

Types of plinth used in construction

To date, there are three options for the basement, which are used in the construction of residential premises:

• Exit plinth. From the name you can understand that such a coating goes beyond the outer walls of the house. This kind of basement will be used if they want to achieve additional heat resistance during frosts, or if this is required by the style of the building itself, because from an aesthetic point of view this option is more attractive. So that water does not linger on the surface of the base, it is usually equipped with grooves or a drainage system.
• Plinth end-to-end with external walls in recent times is used extremely rarely. This fact is due, first of all, to the absence of any useful properties in this type of base.
• The recessed base will be used in the construction of residential buildings. Erected 6 cm deeper than the plane of the outer walls, this type of plinth can save money on the organization of water runoff, and also ensure the safety of the waterproofing layer.

What should be the width of the plinth

The dimensions of the basement directly depend on the material from which the walls of the building will be built. Such information is always contained in the general plan and on the project drawing. With walls made of foam block (which is sometimes also called gas silicate brick) with a long surface of 60 cm, a width of 30 cm and a height of 20 cm, the masonry must have a thickness of at least 30 cm.

If further construction involves the equipment of an additional insulating layer on top of the walls, then the width of the plinth should ideally be 38 cm. However, in the case when the brick is used as a decorative element built on top of the walls of foam concrete blocks, the thickness of the plinth increases by another 22 cm, after which it will be at least 60 cm.

Determining the height

Until now, the masters of the construction business do not have an unambiguous answer to the question of what should be the height of the basement. As the level at which the upper point of the masonry should be, it is best to take the height of those that have fallen in a few recent years atmospheric precipitation. This masonry technology is the most reliable and guarantees a long service life for a future building erected on a brick strip foundation.

But in practice, the most common basement masonry with a height equal to the floor of the first floor in the building. This technique also applies to buildings with a basement. Fashion and style trends in our time imply the presence of a high and massive plinth in the house, which are able to highlight the living space, giving it elegance and elegance.

Insulated brick base on a strip foundation

We remind you that all work on the organization of the basement is carried out on the erected tape base.

We outline the corners

One of the most important rules in the construction of not only the base, but any building in general, can be considered the correct definition of the corners of the structure. Negligence in this matter will certainly lead to a curvature of the surface of the walls, which will eventually lead to their partial or even full bearing capacity.

Several technologies are used to correctly set the corners, but the following technique is considered the simplest:

1. At all corners of the base of the building, a row of bricks is laid out without the use of cement mortar. In this case, the planned width of the future structure must be observed. The corners are inserted using the building level.
2. Next, measure the length and width on both sides, as well as the diagonals. All readings must match to the nearest centimeter. Measurements are carried out using a tape measure or twine.
3. It does not hurt to check the future walls again for irregularities. To do this, use the same twine.

Base surface waterproofing

In order to ensure reliable protection of the basement masonry from groundwater, care should be taken to organize the upper part of the foundation with an insulating layer, the functions of which can be performed by roofing material folded in half. It is glued to the surface of the base using bituminous mastic, a burner or heated bitumen. Also, glass isol, euroroofing material or an improved type of roofing material, which is based on cardboard - rubemast, is used as a waterproofing layer.

Bricklaying

Having provided the surface of the foundation with a waterproofing layer, you can start laying a brick basement. For fastening the bars, a solution of cement, sand and water is used. When building a basement, only red brick is used without holes and cavities.

They start laying out the base from the corners, placing the rows opposite each other, and covering the surface of the material with a solution 2-2.5 cm thick. After laying out several rows, the surface is checked with a level.

Having reached the minimum height of the base, which is 4 rows of standard bricks, you can begin to build walls. Trim the surface of the basement with decorative stone or siding. It is not uncommon to resort to decorating the basement with finishing tiles. With the help of a basement coating, the strip foundation is leveled with a brick.

If there is a basement floor in the room, holes in the basement for ventilation should be provided. They are located at a height of 10-15 cm from the soil. Dimensions depend on the diameter of the vent pipe. From above, the plinth is covered with a waterproofing layer, the same as the surface of the foundation was covered earlier.

Video about laying bricks on a strip base:

The basement can be a useful room

In the distribution of costs for building a house, the foundation can take up to 30% - 40%, therefore, if you want to save on this part, the minimum height of the basement must still be observed, as a necessary condition for the long operation of the building. The elevation of the supporting structure above the ground performs a number of important functions, and it is provided for in all types of foundations. A properly made plinth fulfills its tasks, regardless of whether a basement, a cellar is built in it, or it is just pillars sheathed with siding for an easy outbuilding.

Basement tasks

The height of the basement above ground level, when building your own house on your own, often pays less attention than the depth of the foundation. It is not standardized so strictly and is not described in the requirements of GOSTs in such detail.

In the foundation, this part, in addition to transferring the load down to the support, performs 2 tasks of its own:

• hydraulic fracturing between soil and walls;
• underground ventilation.

An obstacle to the capillary rise of moisture along materials (concrete, brick, wood) is provided by laying waterproofing along the upper plane of the base. The height to which the basement wall is raised protects against water entering the exterior surface of the building in the form of secondary drops, contact snow cover, soil and debris, as shown in this figure:

A clear answer to the question of why it is necessary to observe the minimum required height of the base above the blind area near the walls of the house is shown by a practical example of a specialist in this video:

Insulation

Regardless of whether it is a one-story house or has several tiers, wooden or brick, the basement is combined into a single unit with the underground part of the foundation with a heat-insulating and waterproofing coating.

The lifting height above the ground is calculated taking into account the protection of the internal structures of the first floor floor, as shown in this drawing:

In this example, the plinth is raised above the zero mark by 0.6 m, since 0.2 m is the thickness of the floor slab. The second component of 0.4 m may be due to the thickness of the snow cover, characteristic of the area and the size of the air, which are located 0.1 m above the snow.

Concrete strip built on with bricks

Monolithic strip foundations to maintain the desired height are often made in a combined (by materials) version. To do this, the above-ground part of the tape with the products is laid out of red burnt brick, as in this photo:

At the same time, one should not unnecessarily arrange a high base (with a margin), as the cost of base insulation increases. Depending on the type of design solution, heat loss from the surface of the protruding base reaches from 10% to 15%. In the case of a high non-insulated basement made of concrete, brick, rubble stone, this value can grow up to 40%.

The influence of the blind area

In design solutions for a light or medium weight house, the basement is usually a continuation of an underground support made of the same material. The minimum height above the ground, permitted by SNiP, is 0.2 m. Support belts with a size of 0.4 - 0.7 m work practically effectively. The insulated blind area along the perimeter of the building allows reducing material consumption by reducing the overall height of the foundation.

One of the parameters that determines the depth of the foundation is the depth of freezing of the earth in a given climatic region. The indicator is given in the following reference table:

The total size of the support (tape, pile, pole) in height in the project will be 0.5 m more (standard requirement).

Minimum plinth

To accept a smaller depth of support at home, allows the option of local insulation, mounted under a concrete pavement around the building.

With the appropriate thickness of the insulation, the absence of basements in the construction project in most areas, in order to obtain a stable capital support for the cottage, it can be limited to pouring MZLF with manual digging of trenches and installation of low formwork, as in the following photo:

The concrete blind area protects against the penetration of water from the surface of the earth to the foundation materials, but it is necessary to provide an effective barrier against moisture flowing down the wall down to the basement during rain. It will depend on the selected type of wall and base mate:

1. Speaker. The basement part of the foundation is wider than the walls and requires an additional installation of a visor along the upper edge, which protects the surface located under it from flowing precipitation. Another function of such a visor is a decorative decoration of the facade of the building.
2. sinking. The most reliable option, in which the junction of the outer wall and the basement plane is made with a step. Kali break off the edge without wetting the foundation, which increases the safety of operating conditions for the base material in combination with a waterproofing coating. In this type, there is no need to install fenders for drains.
3. In the same plane with the wall. It is not popular, since it still requires the construction of a protective visor that sticks out on the surface.

In order to understand the need for this measure (protection from water from the walls and its removal along the blind area to the drainage), you can calculate the average number of flowing liters in your area: the average rainfall × wall area × 30%.

Useful plinth

If desired, it is possible to arrange a cellar or a large basement in the underground space of the foundation, if the result of the conducted surveys of the engineering and geological characteristics of the construction site allows.

For specific construction conditions, it is possible to calculate how to equip a useful room even for a private house standing on screw piles, a support in the form of a slab, flooded soils or flood groundwater rises to a mark of less than 2 m from ground level.

SNiP 31-01-2003 of the Russian Federation considers the basement to be a room below ground level at a depth not exceeding 1/2 of its height. The height of the above-ground part cannot exceed 2 m.

Structurally, the device of such a foundation with a basement level differs little from the usual deepening.

The base of the concrete slab view is poured to the calculated depth and walls are erected on it. The tape base is made monolithic or from foundation blocks, its deaf underground part evenly passes into the basement wall with windows and air vents.

Monolithic plinth on a slope

An example of installing a monolithic first floor on a slab is visible in the photo:

The characteristics of materials for such construction will depend on the characteristics of the soil and climate in a particular area. On dry, stable soils, hollow blocks with a low mass can be taken. Their main advantage is low thermal conductivity, which reduces heating costs during the construction of an operated basement level.

To get a useful room for various needs without increasing the area allotted for the construction of a private house, allows the foundation with a technical room, a cellar or a garage, laid down in the terms of the assignment at the stage of drafting the project.

If the placement of useful rooms in the basement is envisaged even before the start construction works, then you can get a tangible effect from the invested costs. But when the building has already been commissioned and is in operation, the need to maintain the stability and bearing capacity of the finished foundation imposes significant restrictions on the possible layout of the basement space and technological operations for its equipment.

Plinth height country house above ground can be very different. It is influenced by several factors at once, ranging from the type of foundation to the depth of groundwater. Many homeowners who build on their own do not pay due attention to the issue of the height of the basement of the building, because they are sure that it is quite enough to make the base slightly elevated above the ground in order to continue construction work.

However, this is not enough. You need to understand that the basement is the above-ground part of the foundation of the house. The higher it is from the surface, the more difficult it is for moisture from the ground to penetrate into the living quarters. The walls of the basement must be separated from the walls of the first floor with a waterproofing layer. This is done so that moisture that could penetrate the base material does not penetrate through the capillaries into the wall material. The level of humidity in different parts of the house can vary significantly, and this must be taken into account during construction.

If the walls of the building are too low, the structure and the main Construction Materials will constantly get wet, their heat-insulating properties will be worsened, and internal destructive processes will begin to occur. Gradually, these processes lead to the complete destruction of building materials from the inside. As a result, the life of the structure is significantly reduced, and the owners sometimes cannot determine why this is happening. And the answer is simple - the insufficient height of the base above the ground.

standard height

In normal country house the base should rise above the ground by about 30-40 cm. If the building is built of wood, then it is better to take a larger height (about 60-80 cm). If the country house provides for the presence of an underground floor, then the height indicators can reach 1.5-2 meters.

When determining the height of the base, it is required to take into account the weather conditions on the ground: indoor and outdoor temperature in winter, snow level, abundance of precipitation, the likelihood of flooding, groundwater level. It is quite difficult for a non-professional to take into account all these factors. Therefore, even if you are building a house yourself, it is best to turn to specialists for the correct calculations. One-time insignificant costs at this stage will help to avoid further serious financial losses for repairs and re-equipment of the structure.

Typical dimensions and scheme of the device of the tape monolithic base.

To clearly understand what is the meaning of a certain height of the basement, it is necessary to consider several main functions performed by this part of the building:

• The plinth prevents the internal structures of the house from getting wet.
• With the help of the plinth, the finishing materials of the building (for example, plastic panels) are protected from contamination.
• There is a compensation for soil shrinkage observed due to the impact of the weight of the house structure.
• If a strip or column foundation was used to build a house, then the distance from the ground to the floor will affect the duration of the operation of the floor, which is often made of wood. In addition, the thermal insulation characteristics of the subfloor will depend on this indicator.
• The plinth helps to ventilate the underground with high quality.
• Among other things, the plinth is an architectural solution that affects the overall visual impression of the building.

Experts recommend paying special attention to the height of the plinth in wooden buildings, because when the lower rims rot, it becomes very difficult to carry out any repair work. That is why developers are striving to reduce the likelihood of wood rotting by increasing the height of the base. But with independent construction, the owners often, on the contrary, reduce the height of the basement, trying to make the exterior of the house more aesthetic. Thus, they make a serious mistake.

The main disadvantage of a high base can be called the fact that with its increase the cost of construction work will increase.

Types of plinths

Plinth construction methods will vary depending on the type of building foundation. In our country, either a tape or pile foundation is most often used. Also very popular is the monolithic foundation.

Plinth made of brickwork.

If a strip foundation was erected, then the base can be made in two solutions:

1. Monolithic. In this case, the foundation is made in the form of a concrete wall. Such a plinth must be built along with the pouring of the foundation.
2. Masonry. When implementing a masonry base, the foundation is made to the level of the soil, then brick (or from other building material) masonry is made. Such a design cannot boast a high level of protection against various influences (when compared with a monolithic alternative), so additional cladding and finishing is necessary.

When using a pile foundation above the ground, it is accompanied by some difficulties. The height and thickness of the base in this case is determined depending on the ground part of the piles. The basement with a pile foundation can be hinged or made on a strip foundation.

Home decoration with siding.

The principles of finishing in this case are as follows:

• Finishing work should begin with surface preparation. Optional, but highly desirable to remove all defects in the draft wall. If the walls have significant irregularities, then it is recommended to make a high-quality crate, and not waste extra time on leveling.
• After that, the starting rail is installed, which is mounted in a horizontal position (approximately 40-45 mm above the bottom point).
• Further, the siding sheet is mounted in the guide rail and fixed with self-tapping screws or special fixing elements.
• Then you need to insert the second sheet of siding, sliding it to the previous one. At the joints, it is recommended to leave a minimum gap so that the material can expand without problems when heated. The minimum temperature, by the way, will slightly reduce the thickness of the trim elements.
• Subsequently, in the same way it is necessary.

Naturally, the basement of the building can be finished with any other modern or traditional facing materials. The main thing in this case is to ensure the protection of construction materials from moisture and cold air. In addition, attention must be paid to the blind area and drainage system Location on. With their help, it will be possible to exclude flooding of the underground premises of the house, as well as the effect of moisture on structures.

What does height affect?

From everything that has been said above, we can conclude that the security of the interior of the country house and the building materials used for its construction will depend on the height of the basement. At the same time, it is necessary to determine the height with intelligence and calculation, because with each centimeter of the above-ground part, the cost of construction work will increase. In addition, special attention should be paid to protecting the basement of the building from the cold by placing a high-quality heat-insulating layer in the space between the wall and the finishing materials.

The higher the base, the better if the material for building a house is subject to biological attack and moisture. We are, of course, talking about wood. When building wooden houses, it is best to make the most reliable plinth with effective waterproofing and heat-insulating layers.

If you are having difficulty calculating the height of the basement of your country house, then you should seek help from specialists. Of course, this type of help is not free, however, it is better to incur costs at this stage of construction than to spend money on home repairs in the future.

Depending on the type of structure under construction, certain parameters of the foundation are adopted at the design stage: the area of ​​its sole, on which the width of the foundation also depends (in the case of strip base), as well as the height of the foundation above the ground. In this article, we will try to give a universal answer to the question regarding how high the foundation should be.

Balancing between necessity and redundancy

Considering that the construction of the foundation is associated with a significant cost item for the construction of a suburban building, it is quite understandable that the desire of an individual developer to minimize its parameters. And if the calculated depth and width of the foundation are parameters that you have to put up with, then what about the height of the foundation above the ground? Indeed, in fact, what is above zero is the above-ground part of the house, which can be built from more affordable building materials.

What determines the height of the foundation above the ground

It must be understood that the above-ground part of the foundation of the building serves as a link, a kind of jumper in the adjacent "soil-environment" section. And this site, like no other, during the operation of the building is exposed to external factors: high humidity and temperature fluctuations. Therefore, in order to answer the question “To what height should the foundation of the house be raised?”, We will indicate why it is generally necessary to raise the foundation above the ground:

• for building a basement at home, when part of the foundation takes on the role of a basement. Obviously, the one-piece design is different the best performance than the construction "foundation + basement";
• to protect the walls of the house from high humidity. Even despite the blind area, the lower side of the house will be constantly moistened, so it is better to raise the “foundation-wall” transition as high as possible. How specific? The minimum height of the foundation above the ground is 200 mm, it can be higher. An observant developer in one of the winters can estimate the thickness of the snow cover on the site, to which you can add 100 mm and get optimal height foundation;
• often the foundation rises above the ground due to the construction of the basement. In this case, the height of the foundation is determined based on the design data;
• for column and pile foundations, the minimum height above the ground is also 200 mm. Such an "indentation" from the surface of the earth is necessary so that the heaving soil does not affect the building. It can be larger, for example, if the relief of the construction site has a slope;
• when calculating the height of the foundation, it is also necessary to take into account the possible shrinkage of the house, the value of which depends on the characteristics of the soil and the load on it from the structure;
• an increase in height in some cases prevents the destruction of the material of the walls of the building. This is especially true for wooden buildings, for example, baths. In this case, either a high foundation is immediately arranged (about 500 mm), or a plinth is erected from other building materials

Summarizing the above

It is necessary to determine the height of the above-ground part of the foundation. We take into account a minimum of 200 mm. We estimate the thickness of the snow cover and, if necessary, change the parameters of the base of the building. The higher the foundation is located above the ground, the better, and less effort is needed to maintain the lower part of the house. Optimal values ​​are considered to be 350-400 mm above ground level. Do not forget about the hydro and thermal insulation of the above-ground part of the foundation! These measures will not only preserve the foundation of the building (prevent moisture infiltration and destruction of the foundation reinforcement), but also reduce heat losses.

The elevated part of the foundation is not only an architectural detail of the house, called the basement, but also a constructive solution that allows you to protect the load-bearing elements of the building from the harmful effects of moisture and other adverse effects.

The height of the supporting structure, its depth, the materials used and other parameters are determined at the design stage.

The choice of foundation design

Considering the options for the main bearing element, which is planned to be made under the house, any future owner tries to choose the most economical option. One of the parameters that reduce the cost of construction, many see the height of the foundation.

If the depth of the supporting structure depends on the depth of soil freezing, the width depends on the calculations that determine bearing capacity, then the height of the foundation above ground level seems to be a characteristic that can be painlessly changed to reduce the overall cost.

High Above Foundation Properties

The height of the foundation of the house affects appearance building, allows you to arrange in the basement wiring of engineering communications that are easy to maintain, and also makes it possible to protect the structure of the house from adverse climatic influences, moisture and temperature extremes.

Properties affecting the design and thermal characteristics

Consider the required height if the ground part of the foundation becomes the basement wall

Why it is necessary to increase the height of the foundation above ground level can be understood by examining the following points:

1. The main load-bearing structure of the house, raised above ground level by increasing its vertical size, will be the basement of the building. AT this case it will be a homogeneous structure without a dividing seam, which is done with horizontal waterproofing in the case of a separate plinth and foundation.
2. A house with a high tape frame receives additional guarantees for protection against the harmful effects of water on structures. To do this, the height of the foundation of the house must be determined from the calculation of the excess of the upper cut of the structure above the level of the highest possible snow level, taking into account the most snowy winters. But regardless of this, its height should be at least 30 cm.
3. If the above-ground part of the foundation of the house is a basement wall, then its height is determined taking into account the project documentation constructive solutions, influence I for its increase.
4. When constructing a columnar foundation and grillage using piles, in addition to raising the upper part above the ground, the lower edge resting on piles or foundation pillars must also be 20-30 cm above ground level. This will protect the foundation beams and pile grillages from possible movements of the heaving soil during periods of its alternate freezing and thawing.
5. The height of the structure above ground level, calculated with a certain margin, during the design will compensate for possible shrinkage of the base.

If the height of the foundation of the house above the surface is at least 30 cm, then the floor of the building is above the ground, which makes it possible to reduce its heat loss and the entire house without the use of additional measures for its insulation and without increasing the cost.

Properties affecting performance

A high foundation will make it possible to use the space under the floor

If the house is made of structures that are especially susceptible to the negative effects of moisture and other influences environment, for example, wood, then the high structure of the core will create additional conditions for protecting the material from contact with water and for ventilation, which will ensure the creation of favorable conditions for the proper operation of the building.

The presence of a foundation above ground level in a basement-free room makes it possible to use the additional space below the floor, formed as a result of this, for the location of water supply networks, sewerage, gas pipelines and other engineering systems.

With the height of this space below the floor, which allows a person to be there and fully perform certain operations, the operation and repair of these networks and systems becomes affordable, convenient and reliable.

Having considered and analyzed the positive details in the construction of a high foundation of a house, we can conclude that its use is economically feasible.

High foundation options

In strip foundations, the above-ground part is 4 times the width

In the practice of strip foundations, it is customary to make the above-ground part four times the height of the width. These ratios are determined by calculations for an average house with a shallow load-bearing base with filling the space between the tapes with soil and sand.

The depth of the foundation is usually greater than its above-ground part. If there is space in the house under the floor in the tapes, it is necessary to arrange ventilation holes, which are necessary for the constant ventilation of the underground space.

If the question arises, what should be the tape bearing frame, the following design options with a high above-ground part are considered:

• tape elements with a laying depth below the freezing depth;
• tape elements with a laying depth higher than the freezing depth;
• beams with columnar supporting parts and grillages on piles.

Foundation depth below freezing depth

The sole of the strip foundation with a laying depth below the freezing depth is located at a distance of 1.5-2 m from the ground surface, and a solid wall rises up from it to the top of the entire element. Under the bearing elements, crushed stone and concrete preparation is usually arranged. About what should be the height of the foundation above the ground - the opinion of a specialist in this video:

The total height of the product, taking into account the buried and above-ground parts, is 2-2.5 m.

The depth of laying is higher than the freezing depth

Strip foundations with a laying depth higher than the freezing depth are used for light structures based on buildings. These are houses made of timber, logs, aerated concrete and structures built using frame technology.

The base for such elements is performed with the replacement of heaving soil with sandy. In addition, expanded polystyrene is placed under the sole, due to the thermal insulation properties of which the base does not freeze through and does not exert harmful pressure on the bearing element. The height of such foundations is 1-1.5 meters. For information on how to determine the depth of the foundation, see this video:

The use of columnar or pile structures

Foundation beams or crossbars are supported on columnar foundations, which in turn rest on a base below the freezing depth. Fall asleep under the beams non-rocky soils and arrange a heat-insulating layer of expanded polystyrene. The average height of the beams is 0.5 meters.

Heavy concrete and brick walls can be erected on piled foundation beams and grillages on piles.

Dependence of technical parameters on the type of foundation

The table below shows the dimensions of the foundations and the height of their above-ground part, depending on the type of structure.

When constructing a concrete base according to options 3 and 4, it is possible to increase the height above ground level not only of the top, but also of the lower edge of the supporting structure.

• Why does a house need a basement?
• The basement of the house with two-layer walls.
• Peculiarities of basement waterproofing.
• Elimination of cold bridges in the basement.

The basement is the above-ground part of the foundation. It's a pretty complex knot. where the vertical (plinth, walls) and horizontal (floors and ceilings) structures of the house converge and adjoin each other.

The correct arrangement, waterproofing and insulation of the basement are necessary conditions for the construction of a durable, economical and heat-saving house.

The figure below clearly shows what will happen if the house has a very low base.

Plinth height not less than 20 cm. protects the walls from moisture (in the picture on the left)

The height of the basement of a private house must be at least 20 cm. With a low base, there is a high risk of wetting the wall of the house. The walls will be moistened from splashes when raindrops hit the ground, when snowdrifts melt, or from capillary suction of moisture directly from the ground.

Damp walls lose their heat-saving properties. Water freezing in the walls gradually destroys them. Dirt, dampness, fungus and mold appear on the walls outside and inside the house.

In areas with high snow cover, it is better to make the height of the base not lower than the level of stable snow cover. This rule is especially important for houses with wooden walls.

To protect the walls of the house from moisture emanating from the ground, two lines of defense are created:

• Increase the height of the basement in order to remove the walls of the house as far as possible from the ground - a source of moisture.
• They arrange waterproofing of the walls of the house and the basement in the dangerous zone of moisture.

A high base increases the cost of building a house. Therefore, depending on the design of the walls and, they try to find a reasonable compromise between the size of the basement and the level of waterproofing.

Be sure to arrange between the basement and the wall of the house ghorizontal layer of rolled waterproofing.

In some cases, which are discussed below, it is necessary to do additional waterproofing of the walls of the house.

For a private house it is recommended to make a sinking base. At the sinking basement, the outer surface of the wall protrudes beyond the border of the basement by about 50 mm. Water falling on the surface of the wall flows down and falls from the wall past the basement onto the blind area. This solution does not allow water flowing down the wall to fall on the horizontal waterproofing and flow through it into the wall. For better water drainage a dropper is fixed along the lower edge of the wall.

It should be noted that in addition to the moisture-proof function, the plinth plays a certain role in the architectural appearance of the house. A house on a high plinth looks more solid and spectacular, and the plinth finish can emphasize the beauty of the floors of the house.

Correct basement of a house with single-layer exterior walls

The height of the basement of a house with single-layer external walls must be at least 50 cm.(shown on the left) Or for plinth height less than 50 cm, but not less than 20 cm., additional waterproofing of the walls is required. (pictured right)

The outer surface of single-layer walls is less protected from moisture than that of multi-layer walls. Therefore, the basement of a house with a height of at least 50 cm.

If the plinth of a single-layer wall is below 50 cm., then arrange additional waterproofing in two places:

1. In the wall, above the first or second layer of masonry of aerated concrete or porous ceramic blocks, another layer of rolled waterproofing is laid.
2. The outer surface of the wall, in the area of ​​the lower rows of masonry, is protected from water by a layer of vertical waterproofing. To do this, it is enough to use hydrophobic primers and water-resistant plasters when finishing the wall. It is better, but more expensive, to clad the plinth and the lower part of the walls with a material with low water absorption, for example, clinker tiles.

Plinth construction for a single-layer wall basement houses or at home on foundation - slab can

Dimensions of the basement of a house with two-layer outer walls

The minimum height of the plinth for a two-layer wall insulated with polystyrene foam is 20 cm. For a wall insulated with mineral wool, at least 30 cm.(in the left picture) A low plinth will lead to wetting of the exterior finish and soaking of the mineral wool insulation (in the picture to the right)

Besides, thermal insulation of the plinth eliminates the cold bridge through the plinth and the load-bearing part of the wall, bypassing the thermal insulation of the floor and wall.

In a single-layer wall, the floor is raised to the level of the second or third row of masonry. The vertical waterproofing of the basement is raised to the same level. 2 - waterproofing; 4-5 - plaster on the grid; 8 - finishing; 9 - floor on the ground

If on site or weakly heaving, then the task of combating the forces of frost heaving is not worth it. In this case, it is necessary to get rid of only the cold bridge through the base and the bearing part of the wall.

To eliminate the bridge of cold in a house with single-layer walls without basement insulation, it is necessary to raise the floor to the level of the second or third row of masonry blocks of the outer wall. This is sufficient, since the material of a single-layer wall has a low thermal conductivity.

The bearing part of two- or three-layer walls is usually made of a material with high thermal conductivity. To eliminate the cold bridge in two-three-layer walls, only the upper part of the basement can be covered with insulation, by approximately 0.5 m. below floor level. This will increase the length of the heat flow path along the base.

If the basement space under the house is not heated, then the basement is covered with thermal insulation on both sides.

In multilayer walls, to eliminate the cold bridge, one outer or both sides of the basement are covered with thermal insulation (for houses with unheated basement space or floors on the ground)

For multilayer walls, another way to deal with a cold bridge is used. The lower rows of masonry of the bearing part of the wall are made of wall material with low thermal conductivity. The floor level is raised, similar to how it is done for a single-layer wall.

For insulation of the basement and the underground part of the foundation, extruded polystyrene foam slabs (penoplex, etc.) are best suited.

It is convenient to insulate strip foundations. The design of pile foundations with bored (including TISE) or screw piles is more suitable for a cold basement. Insulation of such foundations is quite problematic and expensive.

The basement space of houses with pile foundations is usually not insulated. The design of the basement and the floor of the first floor of the house on a pile foundation is chosen taking into account this circumstance.

Next article:

Previous article: