What does the width of the base affect? The optimal height of the basement of the house above the ground

Does the house need a basement?

The basement is the above-ground part of the foundation. This is a rather complex unit where the vertical (basement, walls) and horizontal (floors and ceilings) structures of the house converge and adjoin each other. Correct device, waterproofing and insulation of the basement are necessary conditions for building a durable, economical and heat-saving house. The figure below clearly shows what will happen if the house has a very low base.

A base with a height of at least 20 cm protects the walls from moisture (in the picture on the left). A low base and lack of a base leads to moisture in the wall of the house (in the picture in the center and on the right).

The height of the base of a private house must be at least 20 cm. With a low base, there is a high risk of the house wall becoming wet. The walls will be moistened by 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.

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

• Increase the height of the base in order to remove the walls of the house as far as possible from the ground, the source of moisture.
• They waterproof the walls of the house and the basement in the dangerous zone of exposure to moisture.

A high base increases the cost of building a house. Therefore, depending on the design of the walls and foundation of the house, they try to find a reasonable compromise between the size of the base and the level of waterproofing. Be sure to install a horizontal layer of rolled waterproofing between the base and the wall of the house.

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. In a sinking plinth, the outer surface of the wall protrudes beyond the border of the plinth by approximately 50 mm. The water falling on the surface of the wall flows down and falls from the wall past the base onto the blind area. This solution prevents water flowing down the wall from reaching the horizontal waterproofing and flowing along it into the wall. For better outlet water along the lower edge of the wall is fixed with a drip line.

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

Correct base houses with single-layer external walls.

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

The outer surface of single-layer walls is less protected from moisture than multilayer walls. Therefore, it is recommended that the basement of a house with single-layer external walls be at least 50 cm high.

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

• In the wall, above the first or second layer of masonry made of aerated concrete or porous ceramic blocks, another layer of roll waterproofing is laid.
• 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 waterproof plasters when finishing the wall. It is better, but more expensive, to line the base and lower part of the walls with a material with low water absorption, for example, basement siding, clinker tiles.

The design of the plinth for a single-layer wall of a house with a basement or a house on a slab foundation can be found here.

Dimensions of the basement of a house with two-layer external walls.

Minimum height plinth for a two-layer wall insulated with polystyrene foam 20 cm. For a wall insulated with mineral wool, at least 30 cm is recommended. (in the left picture). A low base will lead to moisture exterior finishing and soaking mineral wool insulation (in the picture on the right).

In a two-layer wall, with plaster over insulation, the polymer insulation does not absorb moisture and serves as an additional barrier to water, protecting the wall from moisture.

Mineral wool insulation for external walls, as a rule, has a hydrophobic (water-repellent) impregnation. However, they are able to absorb some moisture. For walls with mineral wool insulation, the height of the plinth should be increased - the height of the plinth is recommended to be at least 30 cm.

A low base leads to moisture and rapid destruction of the outer wall finish. As in the case of a single-layer wall, with a plinth height of less than 50 cm, the exterior finishing in the lower part of a two-layer wall must be additionally protected from moisture by vertical waterproofing. The role of the drip line in a two-layer wall is usually played by the starting strip, on which the bottom row of insulation boards is installed.

Height and waterproofing of the plinth for a three-layer wall.

In a three-layer wall, water may appear at the border of insulation and cladding. For protection, drainage holes and additional vertical waterproofing.

In a three-layer wall with brick cladding or with a ventilated facade, water may appear at the border between the insulation and the cladding. Water appears when water vapor condenses, as a result of the vapor permeability of the wall material, or enters from the outer surface of the cladding when it is moistened, for example, by slanting rain. Emergency soaking is also possible for various defects in cladding, roofing, etc.

For the reasons stated above, water can appear at the boundary of the insulation and cladding, both in walls with and without a ventilated gap. Both in walls with polymer insulation and in walls with mineral wool insulation.

Drops of water flow down and collect on horizontal waterproofing base The design of the cladding should allow water to drain out of the gap. To do this, for example, in brick cladding, part of the vertical joints of the lower row of masonry is not filled with mortar. Drainage holes left in the masonry every 0.8 - 1 m. Water through these holes has the opportunity to drain out without accumulating on the horizontal waterproofing of the base.

If there is a ventilated gap between the insulation and the brick lining, these same holes also serve to allow air to enter the ventilated gap. To prevent water from the horizontal waterproofing of the base from leaking into the house, it is recommended to additionally install vertical waterproofing between the insulation and the wall to a height of approximately 15 cm.

Insulation of the basement of the house.

Developers usually always pay enough attention to insulating the external walls and floors of the first floor of the house, but often neglect to eliminate the cold bridges in the basement through which heat escapes from the house.

In the basement of the house, a cold bridge may appear through the base and load-bearing part of the wall, bypassing the insulation of the wall and floor.

When building a house on heaving soils, it is recommended to insulate the base and underground part of the foundation to a depth of at least 0.5 - 1 m from the outside with a layer of insulation. This insulation option is for different designs the wall is shown in the pictures above.

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 base is raised to the same level. 2 - waterproofing; 4-5 - plaster on mesh; 8 - finishing; 9 - floor on the ground.

Insulation of the base and foundation allows you to eliminate or reduce the depth of soil freezing in the basement space with wooden or concrete floors on the ground, as well as under the base of the foundation. This reduces the impact of frost heaving forces on the house structure.

If we supplement the vertical thermal insulation of the foundation with a horizontal thermal insulation skirt, we will get the design of a thermally insulated foundation - the best for a private house. In addition, the thermal insulation of the base eliminates the cold bridge through the base and the load-bearing part of the wall, bypassing the thermal insulation of the floor and wall.

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

To eliminate the cold bridge 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 outer wall. This is sufficient, since the material of a single-layer wall has low thermal conductivity.

The load-bearing part of two- or three-layer walls is usually made of material with high thermal conductivity. To eliminate the cold bridge in two- or three-layer walls, you can cover only the upper part of the base with insulation, approximately 0.5 m below the 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 multi-layer walls, to eliminate the cold bridge, cover one outer or both sides of the base with thermal insulation (for houses with an unheated basement or floors on the ground).

For multilayer walls, another way to combat the cold bridge is used. The lower rows of masonry of the load-bearing part of the wall are made of wall material with low thermal conductivity. The floor level is raised in the same way as for a single-layer wall.

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

Convenient to insulate strip foundations. The design of pile foundations with bored (including TISE) or screw piles is more suitable for a cold base. Insulation of such foundations is quite problematic and expensive. The basement space of houses with pile foundations is usually not insulated. The construction of the basement and floor of the first floor of the house on pile foundation are chosen taking into account this circumstance.

The plinth is the outer wall of the foundation on which the façade rests. At the same time this top part basement walls, if one exists. The height of the plinth depends on the type of base, common project house, the nature of the soil, the purpose of the basement. There are certain building regulations in this regard.

How tall should the base be?

Some homeowners believe that if there is no basement, then there is no need for a basement; they can make the foundation flush with the ground.

This is mistake. The main task of the plinth is to isolate the façade from contact with the ground. And to prevent soil water from rising from the ground through the concrete by capillary action, a layer of roofing felt is laid between the façade and basement walls.

The base must be high enough regardless of the facade materials: wood, foam and slag concrete, and brick are equally affected by 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 ground, the lower part of the house suffers from it to the greatest extent);
• protects the casing from mechanical damage ( plinth cladding orders of magnitude stronger than the façade);
• compensates for shrinkage due to the load from the house;
• isolates the basement ceiling (most often wooden) from harmful influences;
• increases thermal insulation characteristics basement;
• gives the appearance of the house aesthetic completeness.
• provides its full value (usually located in the basement of the foundation);

When designing a plinth, the climate (average temperature in cold weather) and average annual precipitation should be taken into account. You can determine the minimum height of the plinth for your site empirically: measure the depth of the snow cover over several winters and add 10 cm of reserve 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 preferred distance from the ground surface is from 50 to 90. If there is a basement floor, the recommended height of the basement can reach 2 meters.

A high base is more expensive than a low one due to the increased volume of concreting work. But when calculating, savings come in second place, strength and durability come first. performance characteristics, which largely depend on the façade material.

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

• recessed - the plane of the base is recessed inward relative to the facade. 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.

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

Options for foundations according to the height of the base in a private house

There are design differences between plinths on low foundations (strip, pile-strip, slab) and elevated ones (pile,). In the first case, no air gaps there is no gap between the ground and the first floor ceiling, the internal space is completely covered with concrete or 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.

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

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

Increased attention is paid exterior decoration, not so much for aesthetic reasons, but for protective reasons. In any case, a blind area is performed (at least to remove it from the base atmospheric waters), and with a high occurrence of groundwater - the 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 high. Columnar, usually elevated. Since it is considered the most unstable, the height should be at least 20 centimeters (to compensate for soil heaving). To ensure sufficient thermal insulation of the interior of the house, the gaps between the pillars/piles are bricked and closed asbestos cement slabs or wooden/plywood panels.

example of insulation of the base and trim pile-screw foundation

example of basement insulation outside a pile foundation

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

What is the optimal height of the basement?

All of the above does not depend on the presence of a usable basement. The basement floor is an important decision from the point of view of rational space planning in the house and on the site. Suitable for solving almost any problem: if desired, you can equip here not only a cellar or boiler room, but also a study, home theater, or bedroom. Even taking into account additional expenses on the foundation high plinth height for one-story house will cost less than installing a second floor.

Floor characteristics according to standards:

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

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

Usually project documentation The height of the basement of the house has also been approved, however, in an effort to reduce costs for the foundation, the owners of the future building doubt the advisability of this size if they are not going to use it, that is, build a basement or furnace room. However, this important point for the entire facility, on which not only the quality and stability, but also the durability of the entire building depends. Below are recommendations for optimal solution in terms of determining parameters.

Base - purpose and types

The ground floor, or as it is commonly called, the basement, is the above-ground part of the foundation that carries great importance both in design and operational terms. The following points depend on it:

1. Protecting the house from interaction with soil moisture.
2. Stable position of buildings with more than one floor.
3. Compensation of the load of the entire object on the ground during shrinkage.
4. Possibility of placing boiler rooms and cellars with an indispensable condition of ventilation. In this case, the height of the base wooden house must take into account the dimensions of the equipment inside the ground floor.
5. Individuality in the matter of architecture.

The types of plinth differ according to the architect's plan in relation to load-bearing walls and there are:

1. Speakers. This is a classic form that provides stability to the entire building, however, such a base must be protected by ebbs for water drainage.
2. Level with the walls. It is inexpressive in appearance and does not receive protection from humidity.
3. Falling, that is, the walls go beyond their edges. For ignorant people, the shape evokes the opinion that the residential structure as a whole is unstable, although it is reliably protected from moisture.

Not installing a base means dooming the wooden object to rapid decay and, as a result, destruction. The savings on the basis will be mythical.

Determining the dimensions of the plinth

The structure of the above-ground part of the foundation is influenced by many factors. What height of plinth is preferred depends on the purpose and conditions of existence of the object.

The ratio of heights to a specific level is established by the design bureau in agreement with the customer, however, the following are strictly taken into account:

• The depth of the foundation.
• The capriciousness of the soil and the level of occurrence of aquifers.
• Climatic conditions of the area and freezing.
• Installation of heating devices in the basement floors or for other purposes.
• The overall height of the object.
• Ventilation of the ground floor.

The specific regulation for the minimum size of such a parameter as the height of the base, SNiP provides for at least 20 cm for monolithic slab. But based on the fact that the strip foundation has become widespread, and the snow cover in middle lane Russia is approximately 1 m, then the ground floor cannot be less than this. Plus a blind area of ​​0.2 m.

It becomes clear that the total height will be 1.2 m. For wooden log houses made of light beams, an increase in height is recommended.

Features of the base and its height during construction

They are based on the prevention of capillary processes and heat conservation - this is important qualities for any structure, and for wood they are also life-determining, taking into account the hostility of moisture and building material. So:

At the design stage, all ideas and changes should be included in the drawings - it is quite difficult to bring sudden desires to life during the construction process. Also, you should not redo the package of sketches and architectural documents yourself - arbitrariness is fraught. In the design bureau, on the contrary, specialists will take into account all the nuances, the implementation of which will only benefit the object.

Always before purchasing materials and starting construction of a building, a plan is created. When designing, it is especially important to choose the right type of foundation, materials for its manufacture and the desired height. Next, we will dwell on the last question in more detail and consider what the height of the foundation can be, the requirements of SNiP and why there should be a certain height for different structures.

Why is the height of the base given so much attention?

The requirements of SNiP quite clearly regulate the requirements for the foundation. It performs the task of supporting the entire structure and if constructed incorrectly, the latter will not be able to guarantee safe conditions for people during operation. In addition, the foundation is constantly affected by destructive factors, and especially in its outer part: winds, rains, snow masses, sun, etc. Therefore, it must not only protect the structure from subsidence, but also raise the wall material two-story house or any other structure to a safe height. Let's take a closer look:

• It’s great to use a raised base as a plinth. In any case, there must be an elevation of the walls above ground level regulated by SNiP. The advantages of using a plinth combined with a foundation are obvious - the structure of the structure will be more holistic and stable.
• Some SNiP of certain materials require their distance from the aggressive influence of the earth: moisture, precipitation, etc. Otherwise, the lower layers of the walls may be destroyed, which can harm the entire building (especially in the case of a two-story house). As for the exact requirements, the base should be 10 cm higher than the calculated level of the maximum possible snow mass in winter period. Simply put, if a lot of snow falls, then the foundation should not be hidden under it. As for the strip base, the minimum height of the foundation above the ground is 30 cm.
• In some cases, the elevated base is a continuation of the basement walls of a two-story house. Similar to the plinth analogy, joint construction will provide many advantages.
• It is possible to create a high base as a measure to combat shrinkage, which is typical for some soils. Experienced planners always take into account all the features of the land at the site where the future building will be located.
• Characteristic elevations are within 20-30 cm for pile foundation, as well as in cases of constructing a one- or two-story wooden house - the tree does not tolerate exposure to moisture.

Please note that even reliable waterproofing walls on the base side will not protect them from moisture and the only way out is to make a base with a sufficient height to protect it from moisture.

Height of strip base

It must be taken into account that the entire height of the foundation consists of 2 parts: underground and aboveground. If you listen to the recommendations of experts, then it is optimal when it rises 40 cm from the ground. This indicator can also be influenced by the amount of precipitation and the material for laying the walls. For example, when using structural aerated concrete, a significantly lower elevation is required than in the case of cinder block.

If there are no special requirements for height requirements, then SNiP documentation should be taken into account when determining the depth. It indicates the freezing levels of the main types of soil and the recommended base heights in each situation:

• The soil is slightly heaving: freezing is 300-350 cm - recommended foundation depth is 150 cm, 250 cm - 100 cm, 150 cm - 75 cm, 100 cm - 50 cm.
• Non-heaving: more than 300 cm - 100 cm, up to 300 cm - 75 cm, 200 cm - 50 cm.

Also, when determining the depth, the level is taken into account groundwater.

Determining the height of a monolithic base

It is worth considering some points:

• SNiP rules regulate the minimum height of such a base at 20 cm. To be more precise, this is exactly what the height of the base should be. But in regions with uneven rainfall, this figure in the case of building a two-story wooden house is increased to 40 cm - this allows you to protect the tree from moisture.
• Also, in cases where the soil freezes to 1 m, the base should be installed deeper.
• The advantages of a monolithic slab include its complete insusceptibility to displacements of soil masses. But in the case of construction in areas with characteristic seismic activity, the width of the foundation should be increased.

General results

• The minimum height of the strip base is 30 cm above ground level;
• It’s great if the foundation performs the task of the base;
• The wall material should be protected as much as possible from moisture;
• It is necessary to make such a foundation that at maximum precipitation it is 10 cm higher than the snow.

Approach the design correctly and it does not matter whether the construction of a two-story house, bathhouse or utility room will be carried out. A well-chosen foundation height above the ground will extend the life of the structure for a long time.

House foundation height updated: February 26, 2018 by: zoomfund

The plinth is the outer wall of the foundation on which the façade rests. At the same time, this is the upper part of the walls of the basement, if it exists. The height of the base 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 there is no need for a basement; they can make the foundation flush with the ground.

house design without a basement

This is mistake. The main task of the plinth is to isolate the façade from contact with the ground. And to prevent soil water from rising from the ground through the concrete by capillary action, a layer of roofing felt is laid between the façade and basement walls.

Base diagram

The base must be high enough regardless of the facade materials: wood, foam and slag concrete, and brick are equally affected by 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 ground, the lower part of the house suffers from it to the greatest extent);
• protects the cladding from mechanical damage (basement cladding is orders of magnitude stronger than façade 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.
• ensures its full ventilation (vents are usually located in the basement of the foundation);

When designing a plinth, the climate (average temperature in cold weather) and average annual precipitation should be taken into account. You can determine the minimum height of the plinth for your site empirically: measure the depth of the snow cover over several winters and add 10 cm of reserve 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 preferred distance from the ground surface is from 50 to 90. If there is a basement floor, the recommended height of the basement can reach 2 meters.

A high base is more expensive than a low one due to the increased volume of concreting work. But when calculating, savings come in second place, in the first place are strength and performance characteristics, 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:

• recessed - the plane of the base is recessed inward relative to the facade. 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 façade walls is small, and also if the project provides for a basement floor.

The advantages of the third option are increased thermal insulation characteristics (a necessary property when constructing a functional 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 recessed base should be minimal, because as it increases, the degree of protection decreases.

Options for foundations according to the height of the base in a private house

There are design differences between plinths on low foundations (strip, pile-strip, slab) and elevated ones (pile, columnar). In the first case, there are no air gaps between the ground and the ceiling of the first floor; the internal space is completely covered 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 of a house with a pile foundation

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

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

diagram of a brick plinth on a strip foundation

Increased attention is paid to external decoration, not so much for aesthetic reasons, but for protective reasons. In any case, a blind area is performed (at least to divert atmospheric waters from the base), and in case of high groundwater levels, a drainage system is installed. The maximum height of such a plinth is limited mainly by economic considerations.

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

example of base insulation and piping of a pile-screw foundation

example internal insulation pile foundation plinth

example of basement insulation outside a pile foundation

example of finishing the plinth of a pile foundation

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

What is the optimal height of the basement?

All of the above does not depend on the presence of a usable basement. The basement floor is an important decision from the point of view of rational space planning in the house and on the site. Suitable for solving almost any problem: if desired, you can equip here not only a cellar or boiler room, but also a study, home theater, or bedroom. Even taking into account the additional costs of the foundation, a higher basement height for a one-story house will cost less than installing a second floor.

note

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

Floor characteristics according to standards:

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

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

• Tags: plinth height snip plinth basement floor

The plinth 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 covering is at risk from mold and rot and retains heat less well inside during cold periods. The main condition for a brick plinth on a strip foundation is high strength. Its structure must support the entire mass of the walls of the building. They will help you achieve the required indicator quality materials With high level resistance to frost, moisture and pressure resistance.

Types of plinth used in construction

Today, there are three options for the base that are used in the construction of residential premises:

• Outgoing base. From the name you can understand that this coating extends beyond the outer walls of the house. This type of plinth will be used if they want to achieve additional heat resistance during frosts or if the style of the building itself requires this, because from an aesthetic point of view this option more attractive. To prevent water from remaining on the surface of the base, it is usually equipped with grooves or a drainage system.
• The base is butted with the outer walls in Lately used extremely rarely. Conditioned this fact, first of all, by the absence of any useful properties in this type of base.
• Recessed plinths are used in the construction of residential buildings. Built 6 cm deeper than the plane of the external walls, this type of plinth can save money on organizing water drainage and will also ensure the safety of the waterproofing layer.

What should be the width of the plinth

The dimensions of the plinth directly depend on the material from which the walls of the building will be constructed. 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 installing 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 brick is used as decorative element, built on top of walls made of foam concrete blocks, the thickness of the base increases by another 22 cm, after which it will be at least 60 cm.

Deciding on the height

Until now, construction workers do not have a clear answer to the question of what the height of the basement covering should be. As the level at which the top point of the masonry should be located, it is best to take the height of the fallen points within a few recent years atmospheric precipitation. This masonry technology is the most reliable and guarantees that a future building erected on a strip brick foundation will long term operation.

But in practice, most often, basement masonry is found with a height equal to the floor of the first floor of the building. This technique also applies to structures with ground floor. Fashion and style trends in our time imply that the house has a high and massive base, which can highlight the living space, giving it elegance and elegance.

Insulated brick plinth on a strip foundation

We remind you that all work on organizing the plinth is carried out on an erected strip base.

Marking 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 determination of the angles of the structure. Negligence in this matter will certainly lead to curvature of the surface of the walls, which will ultimately lead to their partial or even complete load-bearing capacity.

To correctly set angles, several technologies are used, but the following method is considered the simplest:

1. A row of bricks is laid out at all corners of the base of the building without using cement mortar. In this case, the planned width of the future structure must be observed. The corners are inserted using a 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 taken using a tape measure or twine.
3. It wouldn’t hurt to check the future walls again for any irregularities. The same twine is used for this.

Waterproofing the base surface

In order to ensure reliable protection to protect the basement 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 bitumen mastic, burner or heated bitumen. Also used as a waterproofing layer are glass insulation, euroroofing felt or an improved type of roofing felt, which is based on cardboard - rubemast.

Bricklaying

Having provided the surface of the foundation with a waterproofing layer, you can begin laying the brick plinth. To fasten the bars, a solution of cement, sand and water is used. When constructing the basement, only red brick without holes or cavities is used.

They begin 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 rads, the surface is checked with a level.

Having reached the minimum height of the plinth, which is 4 rows of standard bricks, you can begin to build walls. Finish the surface of the base decorative stone or siding. It is not uncommon to resort to decorating the base with finishing tiles. Using a base covering, the strip foundation is leveled with bricks.

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

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%, so if you want to save on this part, you must still comply with the minimum height of the base, as necessary condition long service life of the building. The elevation of the supporting structure above the ground surface performs a number of important functions, and it is provided for in all types of foundations. A correctly made plinth performs its tasks regardless of whether it contains a basement, a cellar, or just pillars covered with siding for light household the buildings.

Problems of the basement elevation

To the height of the base above ground level at self-construction own home often pay less attention than to the depth of the foundation. It is not standardized as strictly and is not described in such detail in the GOST requirements.

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

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

The capillary rise of moisture through materials (concrete, brick, wood) is prevented by laying waterproofing along the upper plane of the base. The height to which the basement wall is raised protects against water falling on the outer surface of the building in the form of secondary drops, contacting snow cover, soil deposits and debris, as shown in this figure:

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

Insulation

No matter, cottage or has several tiers, wooden or brick, the base is combined into a single whole with the underground part of the foundation with thermal insulation and waterproofing coating.

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

In this example, the base is raised above the zero mark by 0.6 m, since the thickness of the floor slab is 0.2 m. The second component of 0.4 m can be determined by the thickness of the snow cover characteristic of the area and the size of the vents, which are located 0.1 m above the snow.

Concrete strip built on brick

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

At the same time, you should not unnecessarily build a high base (with a margin), since the cost of insulating the base 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, uninsulated base made of concrete, brick, or rubble stone, this value can increase up to 40%.

The influence of the blind area

In the design of a light or medium weight house, the base part is usually a continuation of the underground support made of the same material. The minimum height above the ground allowed by SNiP is 0.2 m. Support belts measuring 0.4 - 0.7 m work practically effectively. An insulated blind area around 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 foundation is the depth of soil freezing in a given climatic region. The indicator is given in the following reference table:

The overall height of the support (ribbon, pile, pole) in the project will be 0.5 m larger (standard requirement).

Minimum base

Accepting a smaller depth of house support allows for the option of local insulation installed under concrete blind area around the building.

With appropriate insulation thickness, absence in the construction project basements in most areas, to obtain a stable capital support for a cottage, you can limit yourself 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 effective protection from moisture flowing down the wall during rain to the base. It will depend on the selected type of interface between the wall and the base:

1. Speaker. The basement part of the foundation is wider than the walls and requires additional installation a visor along the upper edge, protecting the surface located underneath from flowing precipitation. Another function of such a visor is decorative decoration facade of the building.
2. Sunken. Most reliable option, in which the junction of the outer wall and the plane of the base is made by a step. The stones come off the edge without wetting the foundation, which increases the safety of operating conditions for the base material in combination with the waterproofing coating. This type does not require the installation of bumpers for drains.
3. In the same plane as the wall. It is not popular, since it still requires the construction of a protective canopy that protrudes on the surface.

To make clear the need for this measure (protection from water from the walls and its drainage along the blind area into the drainage), you can calculate the average number of flowing liters in your area: average rate precipitation × wall area × 30%.

Useful plinth

If desired, you can arrange a cellar or a large basement in the underground space of the foundation, if the result of the survey of the engineering and geological characteristics of the construction site allows.

For specific construction conditions, you can calculate how to equip utility room even for a private house located on screw piles, support in the form of a slab, flooded soils or flood rises of groundwater to a level less than 2 m from ground level.

SNiP 31-01-2003 of the Russian Federation considers a basement floor to be a room located 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 structure of such a foundation with a basement level differs little from conventional burial.

View base concrete slab is poured to the calculated depth and walls are erected on it. The strip base is made monolithic or from foundation blocks, its solid underground part evenly passes into the basement wall with windows and 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, you can take hollow blocks with low mass. Their main advantage is low thermal conductivity, which reduces heating costs when building a usable basement level.

To obtain useful premises for various needs without increasing the area allocated for the construction of a private house, a foundation with a technical room, cellar or garage, included in the terms of the assignment at the stage of drawing up the project, allows.

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