The minimum height of the basement above the ground of a one-story house. Height, dimensions, waterproofing and insulation of the basement of the house

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.

What is the height of the plinth?

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

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.

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 value (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 possible one if the thickness of the facade walls is small, and also if the project provides for.

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,). 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 concrete or tape - either the upper part of the tape 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.

The choice depends on the characteristics of the soil, the relief, 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.

Increased attention is paid to the 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 system. The maximum height of such a plinth is limited mainly by economic considerations.

It 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 basement insulation outside the 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.

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).

The content of the article

It is known that a concrete foundation of any type must necessarily rise to some distance above the soil level. Thanks to this, it is possible to achieve isolation of the walls of the building from its base. This prevents the harmful effects of capillary processes that constantly feed the building with soil moisture.

The foundation is in conditions of high humidity almost constantly. This is facilitated by precipitation, groundwater, melting snow masses. Therefore, there must be some minimum height of the foundation above the ground, ensuring the safety and dryness of the walls.

What are the functions of a building foundation?

The foundation, raised above the soil level, is not only a support for the entire structure.

In addition to this main function, it also solves certain tasks:

The height of the foundation of a wooden house

For a wooden house, a sufficient base height is especially important, since preventing the bottom row of wood from rotting is an indispensable condition for building a wooden house. Such a foundation can be made of concrete, brick, metal or wood. The type of foundation can be tape, pile or columnar.

An indispensable condition is high-quality waterproofing of the base. As a mandatory waterproofing, coating materials (bituminous mastic, cement-polymer-based slurry), as well as roll materials (hydroizol, stekloizol, roofing material) can be used.

The optimal height of the plinth is selected based on the climatic features of the area. It usually exceeds the average snow depth by 10 cm. It is desirable to protect the foundation for a wooden house from dampness not only from below, but also on the sides. This can be done by laying ceramic tiles or clinker.

The higher the base of the house, the better its thermal insulation will be, and the longer it will stand without complaints.

Strip foundation height

consists of its aboveground and underground parts. The optimal height of a monolithic strip foundation above the ground is about 35-40 cm. In some cases, this value may vary. But its underground depth depends on the properties of the soil.

According to the provisions of SNiP, the depth of the foundation is determined as follows:

• Freezing of non-rocky soil by 2 m or weakly heaving soil by 1 m - the foundation is deepened by 50 cm.
• Freezing of non-rocky soil by 3 m or weakly heaving soil by 1.5 m - the foundation is deepened by 75 cm.
• Freezing of non-rocky soil more than 3 m or weakly heaving soil by 2.5 m - the foundation is deepened by 100 cm.
• Freezing of weakly heaving soil by 3-3.5 m - the foundation is deepened by 150 cm.

The depth of the strip foundation is very dependent on the level of groundwater. When groundwater is located near the surface, it is categorically not recommended to lay poorly buried foundations.

Regardless of the level of soil freezing and soil characteristics. Groundwater contributes not only to the dampening of the base, but also to its sedimentation, distortions and gradual destruction.

How to calculate the height of a slab foundation?

A slab foundation is usually preferred to be erected on weak, unstable, heaving soils. A monolithic slab is able to endure heaving of the soil and its settlement, without violating the integrity of the entire structure. But this does not mean that it can be laid directly on the ground, that is, to make a shallow foundation. In some cases, this is allowed, but only on rocky and non-rocky soils. In all other cases, the reinforced concrete slab must be buried to a certain level.

Socle - an outer wall rising above ground level, which is a kind of transition between the foundations and the facade of housing construction. This upper part of the building can serve as walls for basements, semi-basements and basements.

The design and construction of the basement of the building requires a thorough approach. Of particular note is such a parameter as height. Too low a plinth will not be able to protect living quarters from moisture penetration. This negatively affects the integrity and life of the building, making living impossible.

The height of the plinth depends on the following parameters:

• base type;
• house building project;
• characteristic features of the soil;
• purpose of the basement, if provided.

Important are the building regulations, which should not be neglected.

The cost of building the foundation and basement make up the bulk of the estimate. And if the project does not provide for the presence of a basement, some believe that the base can be made flush with the ground. This, of course, allows you to save money at the construction stage, but inevitably harms the building itself. The basement is an indispensable part of houses, in the construction of which materials susceptible to moisture are used.

The main function of the basement part of the building is to protect the facade from contact with the ground. A barrier to soil water, rising through the capillaries from the base, becomes waterproofing, which is laid directly between the walls of the facade and the plinth.

Along with isolating the building from the effects of groundwater, the following functions are assigned to the base:

• protection of the facade from pollution;
• protection of the skin from mechanical damage;
• compensation for shrinkage under the weight of the structure;
• isolation of basement floors from negative influences;
• ensuring full ventilation and improving heat-insulating qualities;

In addition, the basement gives the house an aesthetic appeal and a complete look.

In order for the basement part of the building to perform all the functions assigned to it, it must have sufficient height. Otherwise, moisture will penetrate into the living quarters, and the facade of the building will remain unprotected from pollution and mechanical stress.

According to building codes and regulations (SNiP), this parameter should not be less than 20 cm. This is the minimum figure. It is better not to save money and build a plinth with a height of 30 to 40 cm. Structures built of wood are more susceptible to moisture, so the distance above ground level for the lower part should be at least half a meter and reach 90 cm.

The parameter from 20 to 90 cm is the recommended basement height for buildings in which there is no basement in the project. If housing construction is being built with a basement, it can reach 2 meters. To calculate a more accurate indicator of the required height allows taking into account climatic conditions and the average level of precipitation.

Doing it yourself is quite difficult, but possible. For this purpose, the average depth of snow cover over several years is calculated, and 10 cm is added to the obtained value. These data can be obtained by analyzing weather forecasts.

The main types of plinth

The construction of a high basement leads to an increase in the cost estimate. This is not a reason to save. The main thing is that the outer wall, rising above ground level, be strong and have high performance properties.

The height indicator depends not only on the soil, foundation, project, but also on the position of the base relative to the facade wall. It can be done in one of the following options:

• sinking. The outer wall is located inside the front part. This option is suitable for buildings with fairly thick walls.
• Speakers. The plane of the base is pushed forward. This solution is the only possible option for buildings with thin walls and a basement.
• Level. The basement part of the building smoothly passes into the facade, that is, both the upper and lower parts are located in the same plane.

Each type has its own characteristics that affect how the base will be.

How does the type of plinth affect the height?

The protruding plinth is the most expensive option, but it is necessary in cases where the project provides for an exploitable basement. The height in this case should be maximum. Otherwise, it is impossible to achieve good thermal insulation characteristics. There can be no savings in this case.

For buildings that do not have a basement and a basement, it is best to choose a sinking option. The facade overhanging wall becomes an ideal protection for the base of the house from mechanical damage and adverse atmospheric precipitation. The height of such a base is made minimal. The larger it is, the lower the degree of protection.

Plinth height and foundation type

The basement part of the building on a low foundation (slab, tape, pile-tape) is made of bricks or blocks. The first option is less reliable. Blocks allow you to achieve a higher level of security.

Both plinth options require a high-quality finish that provides protective functions. If the groundwater is close, equip the drainage, and if low - blind area. The height of the basement is made no less than the minimum recommended if there is no basement. The minimum figure is taken solely to save money.

The pile foundation is low if the grillage is directly at ground level, and elevated. The most unstable is columnar, requiring mandatory compensation for heaving of the soil. For this purpose, a height of at least 20 cm is made.

The gaps formed between the pillars or piles are laid with bricks, closed with shields or asbestos-cement slabs. The basement cannot be too high due to the design features of the foundation itself.

The height of the basement in the construction of buildings with a basement or basement

Buildings with operated basements are most widely used in private housing construction. The rationality of such a decision is due to the ability to use this part of the building both for household needs, placing a laundry, pantry, boiler room, cellar in the basement, and for expanding the living space, equipping an office, bedroom, gym, and so on.

Sometimes both of these appointments are combined. It all depends on the proposed building area. The main thing is that this approach is more cost-effective than adding an additional floor above ground level. The total height of the base here is much greater than in buildings without a used basement. It, according to SNiP, is at least 250 cm.

The amount by which the basement will rise above ground level depends on the purpose of the basement. If it is supposed to be used as a utility room, it is allowed to take the minimum limit. You can’t save on the basement floor for living rooms, so a small margin must be added to the recommended height.

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

When building your own house, the height of the basement above ground level is often paid 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.

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).

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.

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 provided even before the start of construction work, 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.

How high should the basement of the house be and what does this indicator affect? How to determine the optimal height of the plinth for a wooden house?

Many owners, when building a house with their own hands, doubt whether it is worth paying attention to the height of the basement. Some even believe that it is enough to simply raise the base to ground level, after which walls can be erected.

In reality, this is not enough. It should be understood that, to prevent the occurrence of capillary processes in them. The fact is that the humidity of the lower part of the house and the upper one can vary significantly due to the proximity of groundwater, snow melt and many other factors.

As a result, low-lying walls made of wood or porous materials will get wet, which will not only worsen their thermal insulation qualities, but also reduce the life of the entire structure. The high base of the house will just prevent this process.

standard height

The optimal height of the basement of a residential building is 35-40 cm. For wooden buildings, it is better to make it higher - 50 - 90 cm. For buildings with basement floors, this value can reach two meters.

When determining the height, it is necessary to take into account climatic conditions, such as the average temperature level during the heating season, the amount of snow, etc.

Main functions

Now let's look at all the functions that the above-ground part of the base of the house performs in order to understand what role its height plays:

Note!
The height of the plinth of a wooden house is especially important, since rotting of the lower crown is an eternal problem for houses made of logs and timber.
Therefore, it is necessary to build a foundation from damp-resistant materials.

The only drawback of a high base is that the cost of construction increases. Therefore, many developers, for reasons of economy, are trying to reduce it. However, such savings are not justified.

Types of plinths

Depending on the type of foundation, the methods of erecting the basement may vary.

Consider its device on two types of base:

• Tape;
• Svain.

On the tape

In the first case, the following types of base are usually made:

• Monolithic - the aboveground and underground part of the foundation is a monolithic concrete wall. It is erected simultaneously with the pouring of the foundation.
• In the form of masonry - in this case, the foundation is raised to the level of the soil, after which masonry is made of brick or other material. This design is less protected than a monolithic wall, therefore, it needs additional finishing.

On a pile

As a rule, the greatest difficulty in construction is the construction of a basement on a pile foundation. Its height is determined by the above-ground part of the piles.

According to the type of device, such a base is of two types:

• Hinged structure;
• On a strip shallow foundation.

The easiest and cheapest way is to make the foundation of the first type. It is based on a crate, which is attached to piles around the perimeter of the building. It can be made from wooden beams or metal elements. Further, the crate is sheathed with facing material, for example,.

Note!
The height of the columnar foundation must be at least 20 cm in order to prevent the possible impact of heaving soil on the building.

The second type of foundation is more difficult to manufacture and costly. Its principle is to arrange a strip foundation around the perimeter of the room, on top of which masonry is performed. The advantages of this design include the fact that it insulates the structure much better.

In the photo - a plinth sheathed with siding

Finishing the above-ground part of the base

Despite the fact that the high plinth itself performs a protective function, in order to make the structure more durable, it is necessary to finish it. This will prevent the negative impact of precipitation and, moreover, will make the building more beautiful. As an example, consider plinth siding, as the most popular material.

Brief installation instructions are as follows:

• Work begins with the preparation of the walls - it is necessary to eliminate irregularities. If the geometry of the walls is severely disturbed, then it is more expedient to perform a crate than to align them.
• Then the starting strip is mounted, which is installed strictly horizontally, at a height of 40 mm above the lower point of the future lining.
• Then the panel is installed in the guide bar and fixed with self-tapping screws.
• Next, the second panel is inserted and shifted to the previous one. At the joints, it is necessary to leave a small gap, which will allow the material to expand freely with temperature changes.
• Further, the entire remaining area is sheathed in the same way.
• At the end of the work on the panels, the finishing bar is installed.

Advice!
To insulate the building, heat-insulating material can be laid under the cladding.

Now the lower part of the house is not afraid of any precipitation and other atmospheric phenomena.

Conclusion

From all of the above, it follows that the higher the base, the less problems there will be in the future with heat leakage and the safety of the walls of the house. However, the height must be reasonable, as it increases the cost of the building. At the same time, it is necessary to take care of protecting the base itself by finishing it with reliable material.

For more information on this topic, see the video in this article.