Construction of a foundation on a slope, their types and description. Stepped foundation Stepped house

The decision on the type of foundation and its design is made by the designer. He is guided, first of all, by the general principles of their design: the foundation should not be washed away by water, it must be protected from possible sliding, there must be a stable foundation under the foundation.

It is not always possible to build a house on a traditional strip foundation. There are times when it is necessary to make a stepped foundation. At the same time, it is not enough to have a good design for such a foundation. It is also necessary to complete its design without errors.

In areas with complex terrain, the location of the house is determined not by the cardinal directions, but by the direction of the slope of this relief. Experts do not advise neglecting this requirement, since it is much more important to be sure of a reliable foundation under the house than to benefit from better natural lighting. If the foundation structure cannot withstand the loads, then there will be nothing to illuminate.

On a slope, the stepped foundation should be positioned with its long side perpendicular to it to ensure maximum resistance to soil pressure.

Stepped foundations, some of which are laid deep due to the construction of the basement, are exposed to groundwater. To remove water from the foundation structure, it is recommended to install wall drainage. When building a house on a slope or near a slope, the existing hydrological conditions change, and drainage is mandatory. Otherwise, the water, flowing down, will linger on the foundation walls, moistening them. Water can also go under the house, washing away the soil underneath. If you perform drainage, the water will be effectively drained from the house through pipes, and the foundation will thus be protected. It is better to perform drainage before filling the foundation.

For a small cottage, drainage, as a rule, does not cause problems, which cannot be said about draining large areas. They are connected with the fact that some of the elements pass under the building, and this in turn limits the number of wells, which will be much more difficult to clean. Drains under the foundation or during a transit passage through it are laid in special couplings.

It is very important to organize effective drainage of water that flows from the roof away from the walls of the house. In this case, the correct solution would be to build a separate drainage system that is not connected to drainage.

In some cases, drainage alone is not enough to protect the foundation from groundwater pressure, and additional structures are also needed. Their choice is determined depending on the specific hydrological conditions of the site.

Construction of a stepped foundation

The width of the stepped foundation can be in the range of 50-80 cm, and its height - at least 30 cm. As in the case of traditional strip foundations, the width of the stepped foundation is determined in accordance with the bearing capacity of the soil: the weaker it is, the wider the stepped foundation is needed .

An important condition for the stability of the future foundation is a properly executed foundation pit. The method of its formation is largely influenced by the type of soil. The angle of inclination of the slopes must be such that they do not collapse. Sandy soils are less stable, so an angle of 30-45° is recommended for them. You should not make the angle larger if the sandy soil is held almost to a vertical wall. This happens when the sand is wet, but after drying it will crumble very quickly. For clay, the angle of slope is closer to the vertical and is 50-60°, and for hard-plastic clays of glacial origin even 70-80°.

Each stage of the foundation must rest on mainland soil, so a foundation pit is usually dug over the entire area of ​​the house. They begin to remove soil from the slopes along the foundation line, observing the angle of inclination. If you come across soil that does not have sufficient load-bearing capacity, it must be removed to a more durable soil.

They start digging trenches from the lowest point of the marking, going up. In accordance with the project, the length and height of the steps are measured. To avoid soil shedding at the ledge, it is covered with solid formwork, which most often remains there forever.

First, a layer of lean concrete is poured into the prepared and protected from crumbling trench, which should prevent the soil from absorbing cement laitance.

The construction of formwork for a stepped foundation is a very labor-intensive process. For any type of soil, it is more convenient to use solid formwork, so that its vertical elements are easier to install in places of ledges. The foundation formwork is combined with elements for strengthening the walls of the pit, which were installed when digging trenches.

The general slope of a stepped foundation, by definition, corresponds to the slope of the territory or the load-bearing layer of the foundation. For concrete foundations, the height of the ledge cannot exceed 30 cm. Reinforcement of foundation strips is carried out in the traditional way. Additional reinforcement of the step is carried out only on heterogeneous or weak soils at its location. Steps with a height of more than 60 cm are rarely designed. They are made of reinforced concrete, with additional transverse reinforcement.

Steps higher than 30 cm are designed if the angle of inclination exceeds 18°. To increase strength they are reinforced with anchors. If the foundation is large in width, additional longitudinal and transverse rods should be laid in its lower part. For the exact locations of their placement, it is necessary to make a special calculation.

A stepped foundation on homogeneous load-bearing soils can also be made in the form of brick or stone masonry. This design is typical for mountainous areas, where it is easy to find the right amount of stone. Where there is a difference in height, a steel I-beam is embedded in the masonry, and in the ledge area a slope is made at an angle of 30-45°.

The design of foundation walls with a stepped foundation is the same as with a traditional strip foundation. They can be made of monolithic concrete or in the form of brick, rubble, or block masonry.

This is one of the most difficult cases for construction. The success of building a house on a slope depends, first of all, on the thoroughness of preliminary calculations. If everything is done correctly on paper, then planting the house will not cause problems. When designing a house on a slope, you must first examine the slope for its stability, which depends on the type of soil. For sandy soils, a safe inclination angle is considered to be 27-31°, and for hard-plate clays - up to 70°. If this angle is exceeded, there is a high probability of the slope slipping, but the problem can be solved with the help of piles, retaining walls or anchors (they press the moving soil mass against stable rocks).

To begin designing the foundation, you need to obtain all the necessary data on the stability of the foundation. Water protection can be achieved using circular drainage. A slope is considered safe only if it is protected from the influx of water.

When building a house on a slope, stepped foundations are the most common solution. But there is another thing - the construction of a large basement under the entire house, which allows you to, as it were, cut the house into a slope and install it on a horizontal foundation. On the side where the slope is lower, you can build a garage, and higher up the slope there will be a fully or partially buried basement. When choosing such a solution, you need to take into account the cost of the basement floor. It may be justified on a steep slope, where large berms may be even more expensive. If the difference along the slope at the extreme points of the house does not exceed 1 m, then the basement no longer makes sense.

Weak soil, lying in an uneven layer under the designed house, is significantly deformed by loads and this complicates construction. The main danger in this case is the uneven settlement of the building and the application of concentrated loads on the foundation. As a result of uneven settlement of the house, the integrity of the foundation is compromised and, as a result, walls crack and tear off.

If a geotechnical study shows uneven distribution of load-bearing soils, the depth of which does not exceed 1.5-2 m, then a stepped foundation may be the most profitable solution. In this case, it is necessary to determine the relief or slope of the load-bearing soils and, in accordance with this, design a stepped foundation that will not disrupt the continuity of the foundation strip.

An alternative solution for foundations on soft soils with uneven distribution of the bearing layer is to replace areas of soft soil with coarse sand or fine gravel. However, this solution is quite expensive, especially if the volume of replacement is significant. Sometimes it is much more profitable to use downwells, micropiles (made of lean concrete, reinforced concrete or sand in a geotextile shell). These are cases when the foundation, due to weak soil, is made wide or must be laid deep, and this entails large volumes of excavation work, the need for additional reinforcement of foundation walls or the construction of retaining walls. The optimal decision in this case is made by a qualified geotechnician.

Laying a foundation on an area with an uneven surface is associated with certain difficulties. First of all, for the correct calculation and design of the foundation of a house, a geodetic survey of the construction site will be required, which will reveal the degree of slope of the site, and geotechnical surveys, which will determine the composition of the soil being developed. There is no point in saving on such work, although it does lead to considerable additional financial costs.

Principles for the construction of strip foundations on sloped areas

When starting to design the foundation of a future building, it is worth considering that the higher the level of difference in surface heights, the more complex and labor-intensive the required set of work will be. Modern technologies for constructing a foundation on a surface with complex terrain provide several options for its construction, of which the most applicable are recessed and shallowly recessed strip-type foundations. Their mutual use for buildings on slopes does not create problems during the further operation of the building and ensures high reliability of the structure.

It should be taken into account that in areas with a large difference in height (more than 2.5 meters), strip foundations are not economically profitable. In this case, a pile type foundation is used.

The construction site is protected from the upland side of the slope in order to prevent it from being flooded by rainwater. To do this, a temporary earthen rampart is erected or a drainage ditch is dug, which, after pouring the foundation and making the blind area, are replaced with permanent storm drainage trays. The further volume of work performed depends on the degree of slope of the earthen surface.

Areas with a slight slope

With small unevenness or a small height difference of no more than 10-20 cm, the area can be taken as horizontal. Excavation of soil for a pit or trench should begin from the most elevated part of the site. The deepening is carried out at the same level and does not change along the entire perimeter of the foundation. In this case, it is necessary to take into account the depth of the fertile layer. If its lower boundary in some part of the developed area exceeds the calculated depth of the foundation, then it is necessary to increase the depth of the trench at the highest point, which is calculated by the formula:

Ht = Hpv + Hps, where

Ht – calculated depth of the trench or pit;

Hpv – height difference at the construction site;

Hps is the value of the fertile soil layer.

In some cases, you can get by by cutting off part of the surface of a slight natural slope or adding soil in the lowlands of the construction site. In this case, the fertile layer is first removed and it is strengthened by careful compaction using silicates.

Areas with a medium slope

If the height difference is more than 20 cm, it would be wrong to start developing a trench for the foundation from the highest part of the site, since in this case the base of the foundation at the lowest point may end up on the ground surface or even higher. The lowest part of the site is taken as the base level from which to start.

Digging a trench in the lower part is carried out to the calculated depth, taking into account the possible impact of frost heaving forces, but not less than the thickness of the fertile layer. The entire remaining perimeter of the excavation for the foundation is made at this level. In situations where the difference in heights on the site is greater than the depth of the foundation, the size of the trench to be torn off is taken to be equal to the difference. But in this case, the consumption of concrete when pouring the base of the building will increase significantly. In order to save money, the width of the foundation base can be slightly reduced, but to reasonable limits.

At the end of the work, the finished foundation is backfilled with non-heaving soil, which is carefully compacted layer by layer. Around the building, the soil surface is planned towards the natural slope and a blind area is made.

Areas with a high slope

With significant differences in height - from 1 meter or more, the most economical option for installing a strip foundation is considered to be its stepped laying, which provides for the individual construction of foundations for each specific section.

Before starting work, the construction site is divided into parts to allow the construction of horizontal terraces at different levels, while the height of the ledges should not exceed half a meter. A landslide wall is constructed for each zone. They begin digging a trench from the lowland part, having previously removed the plant layer of soil. Further deepening at each level is carried out according to design calculations.

The stepped construction of a strip foundation requires the mandatory installation of high-quality drainage, since the natural movement of groundwater from the side of the mountain slope after the construction of the structure will become difficult. The possible accumulation of excess moisture will have extremely negative consequences. In this regard, the drainage system is designed in advance. It is installed around the entire perimeter of the house with deepening to the lower level of the trench, taking into account the sand cushion.

It is advisable to carry out this option for constructing foundations only in areas with a large slope, since the cost of such work is extremely high. They can only be entrusted to highly qualified specialists.

Factors to consider when pouring

When constructing foundations on uneven areas with a surface slope, it is imperative to follow building codes and adhere to technology. But a better solution would be to involve professionals. The construction of such foundations has some distinctive features, mainly related to preparatory measures and additional work.

The following important factors that you should pay special attention to will help you get rid of unpredictable consequences in the future.

1. A competent foundation design is a necessary condition for the construction of a facility on uneven sites. It includes calculation:

• base dimensions;
• weight load of the building on the foundation;
• exerted specific pressure on the ground at various points;
• temporary loads.

The hydrogeological assessment of the site allocated for construction and soil analysis are of great importance. To do this, in most cases they resort to drilling exploration wells.

It is worth noting that the construction of foundations on slopes is advisable only on non-heaving soils.

2. Creating an effective drainage system requires careful preliminary calculations. Accumulating moisture is the main source of many troubles, which can lead to slipping and even collapse of the soil in the mountainous part.

3. Mechanical soil consolidation is an important addition to the drainage system when terrain slopes are more than 10 degrees. The most affordable and simplest option is the so-called weight - a bulk layer of denser soil rocks. The additional mass will prevent possible soil movement. In addition, such work makes it possible to form and partially level the construction site, preparing it for digging a trench or foundation pit.

4. The construction of appropriate formwork consists of the complexity of its preparation in the conditions of existing elevation differences on the site. To maintain the horizontal level of the foundation being poured, the formwork at the lowest point of the site is made higher than at the top.

5. Reinforced foundation reinforcement increases the strength of the foundation. For the frame, metal reinforcing bars of large diameter are used or their number is increased. In this case, special attention is paid to the corners of the assembled frame structure, and the lattice elements are placed at a distance of no more than 15 cm from each other.

6. In order to properly fill the foundation with concrete mixture, it is necessary to ensure its continuous supply. When constructing a base on an uneven surface, this factor is of particular importance. Increased loads during the further operation of the building categorically do not allow the underground part of the structure to be poured in several stages, since it is guaranteed to lead to ruptures at the boundaries between the set layers. In addition, careful compaction of the concrete mixture is required during the filling of the formwork in order to prevent the formation of cavities.

The above measures, which must be taken into account when constructing the foundation of a house on areas with an uneven surface, entail increased financial costs. However, the additional work carried out significantly prevents the threat of soil sliding or washout, being a reliable guarantee for the construction of a high-quality foundation and long-term operation of the entire structure.

Buildings have to be erected under different conditions. The design of the foundation part of the house is directly influenced by the composition of the soil layers, the level of their freezing, the height of groundwater and the terrain. The type and technology of the foundation, the depth of the base and the uniformity of its placement relative to the horizon depend on these factors.

What is a multi-level foundation?

The definition of a multi-level foundation is interpreted differently. The marks of the underground structure may be different:

• on the upper cut;
• at the level of the sole.

In the first case, the zero mark is leveled using the basement of the house. The second option involves the construction of a stepped foundation using a certain technology. The presence of such a structure in a project may be due to the construction of a house on a slope or to the presence of a basement only under part of the building, and not under its entire area.

In fact, a multi-level foundation has several ledges in height. It is erected during the construction of a facility on a site with uneven terrain, but in the absence of steep slopes.

The design of the underground part of the house under consideration significantly saves material investments, since the deepening of each section or block is carried out taking into account the optimal design values. With this method of constructing a foundation, it is not necessary to dig too deep trenches in an elevated area, bringing them to the level of the base of the underlying foundation. The laying is carried out in stages, based on the terrain, since the installation of inclined surfaces when constructing the supporting part of the house is not allowed.

Foundation of a single buildingcan be located at different levels, but only in horizontal planes.

Rules for placing a multi-level foundation

The height of the ledges should correspond to the natural topography of the area. The base of the foundation should be deepened, focusing on the slope of the site. In other words, its lowest level will be at the lowest point of the site being built.

The most reliable and stable position of the tape is to place its long side perpendicular to the slope. This condition is considered important for the design of a multi-level foundation, so it should not be missed. Such marking of outlines in plan allows for effective resistance to ground loads.

The direction of the slope of the site is considered a fundamental factor when designing a house on a slope. In this case, the orientation of the building to the cardinal points and wind rose fades into the background. The main thing here is sustainability, and not the principles of indoor lighting.

Construction of a trench and installation of formwork

To erect a strip foundation, it is necessary to dig trenches with the steepness of the slopes specified in SNiP III-4-80*. It depends on the type of soil lying on the site. The width at the bottom of the excavation is calculated taking into account:

• thickness of concrete strip or prefabricated blocks;
• size of formwork with struts;
• distance allowing workers to move along the trench without violating the integrity of the structure being constructed.

In the case of constructing a stepped foundation, soil excavation is carried out manually in tiers, starting from the bottom mark. In this way, continental soil will remain under the base of each ledge. To avoid its collapse, the vertical soil wall separating the steps is strengthened with formwork panels related to the temporary structure. They are removed after concreting the foundation.

You should not dig a trench along the entire perimeter of the building at once. The work is being carried out in stages!

The formwork is installed according to the working drawings. In this case, you will need to strictly observe the dimensions of each step. The boxes are made solid - with end elements, spacers, struts and vertical reinforcing posts. In places of ledges, permanent shields are constructed, so they are cut to the height of the concrete strip.

Drainage of the site

The construction of a multi-stage foundation assumes that there is a large difference in elevations between the lower and upper tier of the foundation. Deep placement of the first stage requires wall drainage, even if the low groundwater level makes it possible to avoid this stage of work. The fact is that precipitation and melting snow will flow down the foundation walls, forming not only trickles of water, but entire streams at the base.

In the absence of a drainage network that collects and discharges water outside the building, erosion of the soil under the foundation base of the lower steps will occur with further settlement and structural deformation of the house. Its restoration will cost much more than performing high-quality drainage. It is necessary to understand that saving in this case will be an unjustified decision.

Secrets of reinforcement and concreting

The underground part of the stepped structure requires specific reinforcement. If the height of the ledge is more than 30 cm, then the frames of two adjacent sections are tied together with vertical rods and additional clamps (at least at two points). In this case, the condition must be met that the reinforcing bars enter the body above the located step. The reliability of the structure is ensured by fixing the curved ends of the rods to adjacent reinforcement cages. This strengthens the foundation and protects the concrete strip from being cut at the junction of multi-level sections.

The location and connection of the reinforcement is indicated in the working drawings.

With a ledge height of up to 30cm, adjacent sections of the foundation overlap each other. The amount of approach is determined by calculations. The steps are connected using anchors or rigid fixation of the frames with vertical rods.

In the case of a multi-level foundation made of prefabricated blocks, the bandaging of the top element should be at least a quarter of its length. In addition, a monolithic concrete belt with mandatory reinforcement will need to be poured around the perimeter. Completing this stage allows you to reliably strengthen the structure.

Concreting of a stepped foundation is carried out in stages. First you need to fill the lower element, and then wait until it gains strength. Only after this can you proceed to concreting the upper area. Otherwise, the pressure of the concrete mass on the fragile step will lead to a violation of the integrity of the laid monolith. For the same reason, dismantling the formwork of a multi-level foundation is allowed only after the final curing of the concrete.

Related works

When constructing a stepped foundation, one should not forget about waterproofing. The technology for its implementation is practically no different from laying roofing felt under a single-level concrete strip. The canvases are laid in the formwork with an overlap of at least 10 cm so that the edges of the insulating material protrude beyond the upper limits of the box.

Foundation walls are mounted on a multi-level tape in the traditional way. They can be made of monolithic concrete or prefabricated blocks.

In conclusion

A stepped foundation is a more expensive structure compared to screw piles. It is not recommended to build it on unstable soils and steep slopes. The optimal width of the tape is 50-80 cm, and the height of the ledges is no more than 30 cm, although these dimensions are not fundamental. They are taken taking into account the bearing capacity of continental soil. The lower it is, the wider the steps become.

The operational qualities of the structure directly depend on the correct construction of the multi-level concrete monolith.

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How to overcome soil disturbances, their types

If you need to build on the shore of a reservoir, certain difficulties may arise due to possible landslides and the steepness of the slopes and ravines.

Construction on slopes is associated with certain features, which consist in ensuring the necessary rigidity of the entire structure of the installed metal frame based on the reinforcement of the mounted frame.

Construction on slopes and soils is determined by a number of specific features that require mandatory adherence to important points in order to obtain the most reliable structures. The steeper the slope, the greater the likelihood that the ground will collapse. If the slope on the site is up to 10%, then the soil is more stable. The following types of soil stability disturbances can be distinguished:

If the slope of the site is less than 10%, then the soil is more stable.

1. Liquefaction due to high humidity.
2. Sliding along soil rock that is under pressure from the thickness of its own layer.
3. Sliding along a curved line.
4. Sliding down a slope at a speed that is less than that of the layers below.
5. Splitting as a result of destruction of the base of the slope.

Installing screw piles for a reliable foundation of the house can help overcome all violations. This will allow you to cope with weak soil, increasing groundwater levels and hard-to-reach areas.

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Slope strengthening methods

In order to strengthen the slopes, various materials are used, taking into account all the features of the relief, slope and depth of groundwater. If the slope is up to 8%, then it is strengthened by plants and trees, the root system of which has a vertical and horizontal strengthening effect on the slope. Plants can be planted in special slope-strengthening structures. The landslide process will be stopped by intertwining plant roots and fastening elements.

If the slope is less than 8%, it is strengthened with the help of the root system of trees and plants

The modern construction industry offers various materials for strengthening slopes. For example, if water flows down a slope, a special tray will direct it in the right direction. The use of logs and stones will prevent landslides on the steepest slopes. It is possible to use artificial structures - geogrids, biomats and lawn gratings. Ceramic and concrete blocks are also used if it is not possible to strengthen the slope with plants. All methods of strengthening slopes are based on various methods of internal reinforcement associated with the “implantation” of the structure frame for the purpose of strengthening it into the soil layer.

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Placing the foundation on a slope

You can build a foundation on a slope by providing a basement floor. In this case, there is no need to install a level platform under the house. To construct the lower floor, the land mass on the required section of the slope is cut out. You can also build an underground garage if vehicle access to the slope is possible.

When constructing it, it is imperative to apply a layer of waterproofing, that is, tar, roofing felt, etc., to the surface of the base of the house from the outside. Laying the waterproofing layer can be done even before pouring the structure. Experts recommend on slopes for terraces located at different levels. After construction, the foundations for the recreation areas continue for the house itself, based on terraces secured by retaining walls with steps.

When the slope angle is more than 15%, the installation of retaining walls made of brick, concrete or boulders is carried out so that all vertical seams that are located in the rows of stones do not coincide. If the walls are high, then the stones are held together with mortar. When laying rows of stones taking into account the internal slope, the reliability and strength of retaining walls increases. Along all boundaries of the territory, the slope should be reinforced with stones, the best of which are granite, limestone and sandy rocks.

A well-designed house can be built on a mountain, the main thing is not to be afraid to do the installation yourself. When placing the base of a house on a slope, it should be ensured that the façade of the house faces an open area so that the whole house looks exclusive and unique. It’s good if a beautiful landscape opens up from the slope.

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What type of foundation is best to choose?

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How to determine the cost of building the foundation of a house

You can determine the costs of what’s to come on the slope based on all the costs that depend on:

1. The required amount of materials for (crushed stone, sand, concrete, piles, etc.).
2. The cost of earthworks.
3. Payments for rental of special equipment.
4. Fees for conducting an examination of the soil composition of a construction site.
5. Costs for and strengthening systems.

Building a house on a slope is not the most convenient option, however, there are some advantages, namely that the building will be protected from seasonal flooding from the slopes. Resistance to windy weather is also an important reason for building the foundation of a house on a slope for its subsequent construction.

To achieve high strength of the structure being built, it is necessary to lay a reliable foundation, which will be one of three types:

1. Stepped.
2. Pile.
3. Tape.

Each of the above options is practical for installing it on a slope.

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Recommendations for constructing different types of foundations on a slope with your own hands

Experts recommend installing a strip foundation if the angle of inclination is not too large. If, after an examination of the soil, no contraindications are found, then the shallow option can be used during construction.

The construction of a stepped foundation will be a more rational option when the slope is steep and there is no possibility of leveling it. When laying the foundation, it is built up in the form of steps towards the slope.

The use of a pile foundation is necessary on soils that have increased mobility and high groundwater levels. Sometimes a combination of pile and strip foundations is used.

Before starting construction, you should make sure that the bearing capacity of the soil on the slope allows you to build a foundation on it. The slope must also have maximum stability. If the slope angle parameters are about 27-31 degrees, then such a slope has sandy soils that are safe for construction. On soil of glacial origin and hard-plastic clay soils, it is possible to build a foundation, even if the angle of inclination is up to 70 degrees.

Construction on a slope is carried out taking into account the following characteristics:

1. The slope angle as the main parameter during construction, on which the type of foundation should depend.
2. The composition of the soil, which determines the depth of the foundation and the features of the drainage system.
3. The height of groundwater, which determines the depth to which the future foundation will be laid. It also determines the choice of type of waterproofing system.

Particular attention should be paid to how the drainage system is created.

Building a house on a slope poses some difficulties. Among other things, the choice of foundation becomes difficult. This issue must be approached with full responsibility, since over time, all errors during construction can lead to negative consequences, for example, subsidence of the foundation, shedding of soil, and flooding of the house. That is why a strip foundation on a slope must be built in compliance with precise technology.

Characteristics of strip foundation

This type of base can be chosen only when the slope is insignificant. It is also worth considering possible contraindications from surveyors. If there are none, then a shallow strip foundation is quite suitable for use.

If the slope is significant, then it is better to choose a stepped strip foundation. Its advantage is the fact that it is constructed in the form of steps that rise in increasing height, depending on the slope. This will help you create a fairly strong foundation with your own hands, which can withstand a significant load that comes from the side of the slope.

But in areas characterized by increased mobility, it is better to avoid using this type of house foundation altogether.

Installing a strip foundation on a slope requires taking into account some important points. In particular:

• slope angle, which is the main parameter when choosing a certain type of foundation;
• soil composition, which affects the depth of the foundation, as well as features of the drainage system;
• groundwater level. This parameter will affect the level of laying the foundation, as well as the features of the arrangement of the waterproofing layer.

Particular attention should be paid to the arrangement of drainage, since the main cause of damage to the foundation located on a slope is water that comes from above and can wash away the foundation of the house.

Preventive measures

Before constructing a building on a site with a slope, you should think about preventive measures. Special measures taken to strengthen the foundation will help to avoid soil shedding. Often the choice is made from two possible options:

• strengthening by mechanical method. To do this, metal spacers are used that are dug into the slope;
• plantings of plants that have a sufficiently developed root system. This method is the most effective and cheapest, which, in addition to its practical function, also performs a decorative one.

Before the actual construction of the foundation, it is advisable to make sure of the high bearing capacity of the specific soil of the site, as well as the level of stability of the slope. According to the standards, a safe slope is an angle from 27 to 31 degrees for sandy soils and up to 70 degrees for clay soils.

Required tools and materials

Regardless of what type of strip foundation you plan to build yourself, whether shallow or stepped, the list of necessary materials and tools is not much different. So, you will need:

• shovel;
• wooden pegs;
• sand, you can use wet;
• cement;
• gravel;
• roulette;
• reinforcing bars;
• welding machine;
• trowel;
• material for arranging a waterproofing layer;
• building level.

Construction planning

This stage of work is the most important, since the quality of the construction will completely depend on the quality of the calculations performed. On the diagram it is necessary to clearly place the diagram of the house. To do this, you need to find the lowest point of the soil. From this mark the foundation itself will go down just below the freezing point of the soil. To this value you need to add about 50 cm for a layer of crushed stone, sand and gravel.

If the land plot is located in an area where strong winds or frosts are often observed, you need to take into account the need for a trench of about 2-2.5 m. The upper part of the foundation should be located slightly above the ground surface.

The main stages of construction of a strip foundation

For independent effective construction of a strip foundation on a slope, there is a certain technology that requires a clear implementation of the stages of work.

1. Preparatory work. Before directly laying the strip foundation, it is necessary to drill so-called exploration wells. They perform several functions simultaneously. First of all, they are a source of water, and at the same time they indicate the level of groundwater.
2. Foundation calculation. To carry out this procedure, it is necessary to determine the possible weight of the building, the snow load, the possible pressure on the ground, as well as the dimensions of the foundation. Afterwards you need to correct all the data. To obtain the weight of a house, you need to calculate its volume mathematically, even if the shape of the future structure is quite complex. As a result of the calculations, you will get a certain number in m3. The amount of building materials is calculated, which will allow us to determine their specific gravity. Knowing these two quantities, it is quite easy to determine the weight of the overall structure. You need to take into account all the equipment that will be located in the house, as well as, in the case of building a garage, the entire car. This quantity is called the payload. The depth of the foundation must be determined based on the soil on the site. If the main soil material is sand, the depth should be at least 0.7 meters, non-heaving soils - 0.5 m, clay soils - more than the depth of soil freezing.
3. Construction of the trench. In order to carry out all the work efficiently, it is necessary to strictly follow the procedure for constructing such a foundation. The depth of the trench depends entirely on the type of soil that predominates in the area being built. If the main soil material is sand, the depth of the trench should be at least 70 cm. In general, we can say that the depth should be about 20-30 cm below the possible level of soil freezing. However, if construction takes place on dry soil, the depth may be slightly higher. But still the minimum size remains 50 cm. The width of the dug trench should correspond to the width of the wall and be slightly wider. Under no circumstances should the bottom of the pit be made at an angle; it must be level. In addition, the trench should not be located in close proximity to pits or cliffs, since such a location can cause shifting, and as a result, destruction of the entire building. In case of a strong surface slope, it is recommended to build a stepped foundation, but the instructions require a strictly horizontal base. If a monolithic structure of this kind is planned, it is necessary to carry out reinforcement. The lower rods must be placed separately on the lower step, and the vertical ones must be placed so that they practically rise to the upper level of the foundation. In addition, it is necessary to additionally add two load-bearing levels to ensure a rigid structure.
4. Installation of sand cushion. This element is required. The main function of the sand cushion is to distribute the load. The thickness should be about 10-15 cm. The laid sand must be carefully leveled, then moistened and compacted properly. In situations where the base of the structure is slightly higher than 40 cm, the sand layer must be additionally covered with a layer of gravel or crushed stone. The thickness of this layer should be identical to the thickness of the sand layer.

   

5. Concreting process. After the reinforcement process, you can proceed to the actual concreting of the foundation. The optimal choice would be cement grade M200, no lower. The process of pouring formwork must be continuous, otherwise the reinforced concrete strip will become very vulnerable at the boundaries of the bays. Particular care must be taken to remove air bubbles from the solution. This can be facilitated by the use of a deep vibrator. After the concrete is poured, you need to give it time to dry completely. This usually takes at least a month. And only after this can we proceed to the construction of the building itself.
6. Waterproofing the base. Despite the fact that the strip foundation on a slope is made of concrete, it needs high-quality waterproofing. As a rule, for these purposes, a hardened concrete foundation requires coating with welded, coated, sprayed waterproofing. It is also possible to use roll waterproofing. Also, do not forget about the design of the drainage system. The concrete strip will prevent the possible movement of a certain amount of groundwater from the hill, which can cause moisture accumulation. The drainage system will prevent erosion of the foundation. When installing a drainage system, it is necessary to take into account the layering of the soil, as well as the size of the slope of the site. In some situations, it will be sufficient to install the system only from the side of the hill, but for higher reliability and confidence that there will be no erosion, it is better to install a drainage system around the entire house. A long service life of a building is only possible if the drainage is of high quality.

A shallow or stepped strip foundation, which was erected without violating building codes, can provide sufficiently reliable support for your home or garage, which is located on a site with a slope, which will serve for a long time. All work can be done without the help of specialists; the main thing is to strictly follow all the advice of professionals in this matter.