Before you start building a house from foam blocks, you need to take into account various factors that affect the load-bearing capacity of the foundation. This will help you choose the right type of foundation, because, as you know, a solid foundation is the key to the longevity of the house.

The advantage of a house made of foam blocks

If we compare a block house with a brick one, it has several advantages. Thus, it is distinguished by good heat and sound insulation properties. In addition, walls made of foam concrete with a thickness of 0.3 m can be compared in terms of their thermal insulation properties with brick walls having a thickness of 1.0 - 1.5 m. Foam concrete is also non-flammable and is considered an environmentally friendly material.

Large block sizes help speed up the wall construction process

On the other hand, foam concrete products also have disadvantages: a higher moisture absorption coefficient than brick and fragility, depending on the lower density coefficient of the material due to the porous structure. And houses made of foam blocks require mandatory finishing and leveling of surfaces.

But all of the above are trifles compared to the affordable price and speed of construction. The main advantage is the lighter weight of the structure compared to brick.. Based on these considerations, many land owners select the foundation for their future home.

Choosing a foundation

The type of structure being built will depend on the load on the foundation - for example, a one-story house on a site with a low groundwater level will suit a shallow strip foundation, and for a two-story house, the best option would be a monolithic slab with good waterproofing and insulation.

This type of foundation is practically indispensable for foam block houses with varying levels of groundwater.

Three types of construction can be considered - columnar, strip and slab.

1. Columnar is erected from round or rectangular pillars - always at the outer corners of the house, at the junction of two walls and along the entire perimeter of the house under load-bearing and non-load-bearing walls.

   Suitable for soils with uneven terrain

2. The tape stretches continuously along the entire perimeter of the house and under the load-bearing walls; it can be arranged shallow or buried.

   Is the best choice when constructing a basement

3. The slab is poured onto a bed of gravel and sand under the total area of ​​the house. It is considered the most reliable of the above, but also the most labor-intensive and costly.

   The slab foundation is usually poured onto permanent formwork.

Features of the construction of foundations of various types

Since foam blocks are a relatively light material, the choice of base will be based on the type of soil, terrain, depth of groundwater and level of soil freezing.

Table: comparative analysis of foundation types

Type of foundation	What type of architecture is it suitable for?	What type of soil is it suitable for?	Construction options: depth, inter-step distance
Columnar	One-story house with relatively light weight	Heaving or peaty soils, soft soils, uneven terrain (height differences between adjacent pole supports may vary)	Possibility of using reinforced concrete pillars or piles or installing brick support pillars; interstep distance - up to 2.5 m, laying depth - to the depth of soil freezing (but not less than 1 m)
Tape	Two or more storey house	Non-heaving soils	Shallow; height of underground and above-ground parts - 0.5 m each
Monolithic	One-story house of small area	Any type of soil (with good waterproofing), but preferably rocky soil	Shallow; laying depth - up to 0.5 m

Since the structure of foam blocks is porous, the base under the house must be well waterproofed. To do this, the surface of the foundation is either covered with a waterproofing layer (liquid waterproofing can be used), or the base is covered with a layer of film before erecting the wall.

Photo gallery: types of foundation waterproofing

Clogging into the pores of the foam blocks, liquid waterproofing fills the voids and prevents moisture from entering there. Not only the base of the house is insulated, but also the floor under the foam blocks. The insulating material is a covering one - film or roofing felt. A layer of roofing felt is laid on the inside of the formwork structure.

What to consider when choosing the type of base

When choosing the type of foundation, we first of all take into account:

• type of soil, level of groundwater, depth of soil freezing;
• the total load of the house structure and the number of floors;
• budget and construction time.

First of all, it is necessary to conduct a soil analysis. At this stage of construction, wells can be drilled in several places on the site to a depth of 2 - 2.5 m. Where water flows at a depth of 2 meters and below, a shallow strip-type foundation is suitable.

If groundwater flows at a level of 0.5 - 1 m, then you will have to build a monolithic, non-buried foundation made of reinforced concrete with mandatory waterproofing of the structure.

For strong, non-heaving soils with a depth of 2 meters and below, the best option would be to install a columnar foundation. This type of base is also suitable for areas with complex (uneven) terrain - with the help of pillars you can adjust the height difference.

Next, you need to calculate the load on the foundation of the house, which will consist of the weight of the walls, ceilings and roof. It should be assumed that the mass of 1 m 2 of a foam block wall is approximately 0.9 tons. By adding here the weight of the floors (as a rule, monolithic slabs are used) and wooden beams for the roof, we get the total weight of the house.

As for the construction time frame and budget planning, the first place is rightfully given to the columnar foundation. The determining factors are speed and lower construction complexity compared to other types of foundation. The most difficult thing is to install ready-made pillars on the site without special equipment; in addition, there is a need to strengthen the structure with a grillage, subject to the construction of two or more floors. The construction speed is a week, the costs are associated only with the purchase of ready-made poles and the rental of special equipment, additional expenses for pouring and reinforcing the supports.

Pouring the foundation for a house made of foam blocks with your own hands

Having determined the type of soil and prepared the construction site, you can begin laying the foundation, having first marked the site.

Video: do-it-yourself foundation marking

Features of laying the foundation depending on its type

Each type of foundation has its own characteristics in terms of the amount and structure of work performed.

Strip foundation

1. First, places for external and load-bearing walls are marked, then, following the marking, a trench is dug at least 0.5 m deep, the width of which will depend on the thickness of the walls. For example, if the thickness of the wall is 300 mm (i.e. the length of one brick), then the width of the foundation should be taken equal to about 500 mm (here it is important to take into account not only the thickness of the wall in the light, but also additional layers of heat and waterproofing layers and finishing).

   After marking the construction site, the second stage of laying the foundation for a block house will be digging trenches for the foundation

2. A cushion with a layer height of 20–25 cm of a mixture of sand and crushed stone is placed at the bottom of the dug trench, after which formwork is installed (removable for the above-ground part of the foundation, non-removable for the underground), and reinforcement is laid in the trench to strengthen the strength of the future foundation.

   For reinforcement, you can use rods with a diameter of 10 mm

3. After laying the reinforcement, the trench is filled with concrete. It should be remembered that the filling is carried out simultaneously throughout the entire trench.

   The foundation is poured simultaneously throughout the entire trench

The base must be left until the concrete has completely hardened within a month - only after this period can you begin to build walls, since during this time the concrete will gain its original strength. If pouring occurs in the summer, it is recommended to wet the foundation several times a day to prevent premature drying of the structure.

The upper (above ground) part of the strip foundation must have a standard height of 0.5 m above the ground surface.

It is also necessary to take into account the groundwater level - if it is high, then the structure must be additionally waterproofed!

As a waterproofing layer, you can use roofing felt, which is fixed to the inside of the formwork structure.

If the formwork is removable, then it is removed after the concrete has completely hardened - dismantling should be done carefully, without damaging the roofing material.

Columnar foundation

Video: how to build a columnar foundation with your own hands

A monolithic foundation resembles a sandwich made of reinforcement, concrete mortar, sand and waterproofing.

A shallow slab foundation will become a solid foundation for a house made of foam blocks

1. For a monolithic foundation, a pit is dug in which a sand and gravel cushion is placed - with a layer height of 40 cm (25 cm - sand, 15 cm - gravel).

   Depending on the type of soil, you can build a foundation pit or not - it is enough to build a formwork structure

2. A waterproofing layer is laid on top of the pillow, thanks to which it is possible to protect the base structure from the effects of groundwater.

   Geotextiles, layers of roofing material or very dense film are suitable as waterproofing materials.

3. After waterproofing, reinforcement is laid on the bottom. According to the rule of reinforcement, rods should be taken with a cross-section of 8–10 mm, laying them crosswise in two layers with a step of 25 cm. This method of laying can increase the strength of the base: the total load of the structure is evenly distributed over the entire area, which preserves the integrity of the slab.

   Reinforcement of a monolithic foundation is carried out in two rows - to enhance the strength of the structure

Video: how to build a foundation for a house made of foam blocks

Setting up a solid foundation for a house made of foam blocks is not a difficult task, and you can cope with it on your own. The main thing is to correctly determine the type of soil and take into account all recommendations for selecting the type of foundation.

In the process of building a house, every stage is important. This statement takes on particular significance when it comes to the foundation. It is the foundation laid for the future building that is one of the most important elements of the overall design. The foundation must take over and compensate for all the negative factors that are concentrated in the soil, and become a reliable base for the construction of the building.

One should not think that lightweight wall materials, which include foam concrete, do not require special attention. A house made of foam blocks has specific characteristics, such as fragility, and they cannot be ignored. Therefore, the foundation base for such a structure must provide a perfectly level base. But due to the fact that the recommended height of a foam block house is no more than 3 floors, and cellular concrete itself is a lightweight wall material, there is no need to weigh down the foundation. This will have a positive impact on the overall construction cost.

Experts highlight the following as the best options for a house made of foam blocks:

• tape (depth depends on soil characteristics);
• columnar;
• monolithic slab.

The pile type of foundation is rarely used.

Choosing a foundation for a house made of foam concrete blocks

In order to correctly determine the appropriate type of foundation base, you need to take into account the following parameters:

• soil characteristics;
• number of storeys;
• climatic conditions;
• construction time;
• financial opportunities.

The decisive factor influencing the choice of an individual developer is the soil on the site. It is advisable to analyze the soil for its type and chemical composition. It is also necessary to determine the level of freezing in winter and the location of groundwater. Without these studies there is no point in starting construction.

Of course, the price for the services of organizations conducting soil analysis will cost a pretty penny, but in problem areas it is better to pay the specified amount and build the correct foundation than to then constantly spend money on major repairs.

What does the soil hide?

• Close location of groundwater.
• Flowability.
• Difficult terrain.
• Water saturation (“wet” soil).

In each of the above cases, a balanced approach is needed. You cannot rely on the experience of neighbors on the site, because even 20 m between buildings is a decent distance, and the soil may have completely different characteristics. When starting construction, the owner must personally conduct research on which foundation is best for a house made of foam blocks. To do this, one or two wells are drilled to a depth of 2 m exactly on the site where the house will be located. Soil samples are taken every 20-25 cm.

Relationship between soil type and foundation type

On non-heaving (slightly heaving) soils, where the freezing depth does not exceed 1 m, and groundwater is below 2 m underground, a shallow strip-type foundation is selected and installed. If the water is located higher, then there is a need for drainage measures, which significantly increases the cost of the foundation.

It is known that the belt type loses a percentage of reliability in direct proportion to the groundwater level. If the indicator is only 0.5 m, then a foam block house will need a foundation in the form of an unburdened reinforced concrete slab. This design resists heaving and soil heterogeneity and evenly distributes the loads from a building of 2-3 floors onto the ground. The slab foundation protects the walls from cracks and the openings from deformation. A popular modern option is the Swedish stove. This is an insulated type of base, designed specifically for foam concrete blocks. The warranty period is 100 years.

A house on clay soil requires a columnar foundation underneath. A similar type is needed on peat-type soils and loams. If the non-heaving layers lie deep (2 m or more) or the area has complex terrain, a pile foundation will be required. The piles are mounted at intervals of 1 m, then it is necessary to perform a good monolithic piping. Pile foundations are installed for small buildings. Mostly these are one-story cottages, less often – houses with two floors. A foundation on screw piles is quite expensive compared to a traditional strip foundation, but in some situations you cannot do without it.

Technologies and construction time

• Shallow tape.

The cheapest arrangement option. For such a base, a flat area with water depths of 2 m or more is suitable. Trenches can be dug manually to a depth of only 0.5 m. The height difference is checked with a water level. The width of the tape should be 10 cm larger than the future walls.

A cushion of sand and gravel (crushed stone) is formed at the bottom of the trench. The sand and gravel base of the foundation must be well compacted to prevent subsidence. Next, the formwork is created and reinforcement Ø10 mm is laid. Concrete is poured in one go.

The foundation must stand for at least 10 days, only after that can you begin laying the walls. But it is better if the foundation hardens for the required 28 days (4 weeks).

• Tape recessed.

Well suited for a house with a basement. Compared to the previous type, it requires more consumables. Otherwise, the arrangement technologies are very similar.

• Columnar.

It is used on clay, peaty, heaving soils, as well as when the soil freezing level is from 1.5 m. The height of the pillars must be at least 1 m and correspond to the freezing depth. Reinforced concrete supports are mounted in the corners of the building, at points of greatest load, under load-bearing walls. The standard distance between posts varies in the range of 1.5-2 m.

This option has an undeniable advantage - the shortest construction time. It is quite possible to complete all the work in 3-4 days, but provided that the height of the building is one floor. For more bulky buildings, the time frame will be increased due to the need for grillage.

• Plate.

It is also called a floating foundation. This type of foundation can be installed on any soil except clay. The rigidity of the structure is achieved through reinforcement. The depth of the foundation depends on the project (house with or without a basement). An important point is waterproofing. In most cases, this type of foundation is performed by a team of specialists on a turnkey basis. The disadvantages are the long hardening time and significant financial costs for materials.

• Pile.

A house built from foam blocks, although lightweight, requires the right foundation. In recent years, builders have decided that the best foundation on sandy soil (after slab) is a pile foundation. The piles are quickly installed. They are an excellent solution for relief areas with problematic soil.

The pile foundation for foam concrete blocks, regardless of the type of supports used (hanging, screw or rack piles), is strengthened with a grillage. Of course, this increases the cost of construction. The obligatory hiring of a team of specialists with equipment can also be considered a disadvantage.

Prices for turnkey foundation installation

By ordering a service from an organization that deals with foundations, the developer ideally receives an excellent foundation for a future house made of foam blocks. At the same time, the owner of the site does not delve into the technology, relying on the experience of professionals.

The brigade undertakes:

• site preparation;
• delivery of necessary materials;
• excavation;
• marking;
• installation and dismantling of formwork;
• reinforcement;
• concreting;
• backfill.

Companies use various methods to set prices for their services. Calculations are used per 1 m2, per 1 m3 or per 1 linear meter. Installation of piles is estimated individually; on a large site, a system of discounts is usually provided.

How much will the work of specialists cost:

View	Cost per linear meter	Price per square meter	Price per cubic meter, rubles
shallow belt	2 600
deep belt	7 800		4 000 — 5 000
monolithic slab	3 200	3 200	3 500 — 4 500
columnar	1 000	1 000
columnar monolithic reinforced concrete			4500 — 5500
pile-screw		775
preparatory work			850 — 1500
Pile installation price (RUB/piece)
bored	1000 — 1500
screw	from 350

Houses made of foam blocks are becoming quite popular, due to the speed of wall construction, high performance characteristics and low material costs. But already at the beginning of construction, most people are faced with the problem of choosing the optimal foundation option for a house made of foam blocks.

Choosing a foundation for a house made of foam blocks

Foam blocks are a high-quality material that can withstand large temperature fluctuations, as well as high degrees of humidity, while maintaining its thermal insulation qualities. But how to choose the right foundation for a house made of foam blocks so that it does not crack over time?

Since foam concrete is light in weight, the foundation for such a house may be less thick, but you need to take into account the size and number of floors of the future building

Since this material is quite light, building a house does not require the construction of a complex and expensive foundation. The type of supporting structure is selected based on the following parameters:

• soil quality (soil type, its composition, groundwater level, maximum freezing depth);
• the total load of the building itself, including the above-ground and underground parts, the weight of the objects located in the house (furniture, engineering systems, residents, etc.);
• degree of secondary loads (snow, wind, rain);
• timing of masonry work and costs of foundation installation.

Soil analysis

Before choosing a foundation for a house, it is necessary to conduct a geological analysis of the soil, the results of which will influence the choice of supporting structure.

The soil may have the following characteristics:

1. Flowability. Usually characterizes weak soil, on which the walls may warp, the building may sag on one side, and the foundation may deform.
2. Water saturation. For this type of soil, it is necessary to carry out drainage work, including drainage of water during the construction period, as well as the installation of a permanent drainage system.
3. High level of groundwater. Here it is necessary to keep in mind that water will wash away and destroy the supporting structure.
4. Difficult terrain. In such conditions it will be very difficult to install some types of foundations.

Conducting soil geological exploration is expensive, so most people do not carry out this procedure, trusting their neighbors who carried out such work before building their house. But you need to know that the type and composition of soil can be completely different even over a short distance.

Therefore, you should make a well about 2 meters deep on your site and then take soil samples every 0.2–0.3 meters.

Soil quality indicators can change even over a short distance

For non-heaving or slightly heaving soil with a groundwater flow depth of more than 2 meters, the best option would be to construct a shallow strip foundation. It must be borne in mind that strip support becomes impractical at higher groundwater flows.

Before installing the foundation, it is necessary to determine the heaving of the soil, the degree of its freezing and the level of groundwater.

If groundwater is located at a depth of 50 centimeters, then a strip reinforced concrete foundation is not suitable, since the work will be complicated by the additional creation of a drainage system. In this case, a support made from a non-buried reinforced concrete slab is best suited.

Sometimes complications can arise when the soil in the area is very poor, and the non-heaving layer lies quite deep (at a distance of more than 2 meters). Here the issue of choosing a base will be acute. If you choose piles, you need to build them in increments of at least 1 meter, and then create a monolithic concrete frame. It is possible to build a columnar structure made of concrete with technological calculations for the maximum load-bearing capacity of the building.

Determination of the degree of load

Foam concrete blocks are a porous and lightweight building material, so a building erected from them will be twice as light as a brick one. The most optimal support option for such buildings in private construction is considered to be a durable solid or strip structure, since it can withstand the heavy load of even high-rise structures. The columnar version is mainly designed for small-sized one-story houses.

The choice of a solid foundation for various foam block buildings is considered individually, since it will depend not only on the main, but also on secondary factors.

Time frames and costs for foundation construction

The columnar foundation structure is the fastest to build, and the entire process can be completed independently in about 3 days of productive work. A longer period will require the installation of a strip or reinforced concrete base, due to complex excavation work, construction of formwork, metal frame and concrete support. In addition, it will take 2 or 3 weeks for it to acquire a sufficient degree of strength.

If we consider the foundation based on the price of materials and the complexity of the work, then the slab and strip foundations are considered the most expensive. A columnar support structure will cost much less depending on the number of elements purchased.

Types of foundation for a building made of foam blocks

There are several types of foundation structures that are used for modern construction of foam concrete houses.

Strip foundation

This type of foundation is a foundation buried in the ground, which is designed to support the entire above-ground structure (up to 3 floors). The interior space of the base can be used as a basement or semi-basement. Features of deepening the strip foundation are as follows:

• a buried foundation is usually installed on viscous clayey or other shallow and dusty soils. The optimal laying depth should be no less than the maximum freezing depth of the soil;

  A buried strip foundation is constructed if a basement is planned under the house, as well as when constructing a two- or three-story house

• The shallow foundation is intended for the installation of a supporting structure on coarse-grained sandy and gravel soils. The recommended laying depth is about 50–60 cm with a backfill of sand and gravel (about 20–30 cm) or sand and crushed stone (about 10–15 cm).

  A shallow strip foundation has a shallower depth and can be installed in strong, non-heaving soil

In order to calculate the volume of such a base, you should know the length, width and height of the planned structure. The width mainly depends on the area of ​​the support and on average ranges from 45 to 50 cm. The height of the structure for a 2-story building will be about 1.5 m.

We calculate the length as the perimeter of the base of the house. So, for example, for a building 6x9 meters with one load-bearing wall, 7 meters long, the perimeter is 37 meters (7+(6+9)*2).

With a foundation width of 0.5 meters, you will need 27.75 m 3 of concrete solution (0.5 * 37 * 1.5).

Slab foundation

A slab foundation is a monolithic reinforced concrete structure that is poured into the ground and is recommended for the construction of buildings on unstable sandy soils.

A slab foundation has a high degree of strength, but is much more expensive than a strip foundation.

The foundation in the form of a monolithic slab can be installed on almost any soil, except clayey

Typically, the thickness of the slab is from 15 to 18 cm. With a house area of ​​54 m2, 972 m3 of concrete solution (54 * 18) will be required. For greater strength of the slab, “stiffening ribs” are installed over the entire area in increments of 2 or 2.5 meters.

Pile foundation

This type of support is usually erected on unstable soil with a large degree of deformation or on sloping terrain. Piles can be of various types.

• screw piles with a thickness of 108 mm and a strength level of 5 to 7 tons are used to build foundations for 1 or 2-story houses made of foam blocks. The distance between supports is at least 2 meters;

  The blades of screw piles ensure entry into the ground with minimal resistance, similar to a corkscrew

• hanging piles ensure the strength of the house due to the frictional force between them and the soil during the process of driving them;

  Piles are called hanging piles, since the supports do not rest entirely on solid layers of soil

• rack piles go deep into the ground to the level of denser soil layers. Such piles are very reliable and can withstand a high degree of load without changing their performance over time.
  

  Rack piles rest on hard soil layers and are able to withstand heavy loads

For all types of pile foundations, formwork is laid on top and an additional grillage of concrete with a metal frame is poured.

Video: calculation and installation of a foundation made of screw piles

Columnar foundation

This type of foundation is usually used to build supports for houses on viscous clay or fine silty soils with a freezing depth of 1.5 to 2 meters. To install such a support, factory poles are usually used or they are poured into pre-dug holes with metal reinforcement.

Mounted at intervals of 2 meters from each other. Also, supports should be placed in the corners of the house and in places with a high degree of load. The depth of laying the pillars should be approximately 15–20 cm lower than the freezing level of the soil. First, a sand cushion is laid under them, and then a special formwork with a bottom, into which a concrete solution with reinforcement is poured.

It is advisable to use a columnar foundation for small one-story buildings

Video: types and properties of foundations

Installation of a shallow strip base

In modern construction, this type of foundation is an economically feasible and reliable technological solution.

Materials and tools for work:

• concrete grade 200;
• metal fittings D 12 or D16;
• wooden pegs and construction twine;
• shovels for digging trenches;
• geotextiles;
• coarse river sand;
• boards or plywood for formwork - thickness 20 mm;
• building level;
• rule;
• vibrator for concrete;
• wire for tying reinforcement;
• nails and hammer.

Strip foundation construction technology

1. We remove the top layer of soil and mark the site, installing wooden or metal pegs along the entire perimeter of the future structure and pulling construction twine. We accurately measure the corners and check the distance between the load-bearing walls with the approved house design.

   According to the markings, all work related to the creation of the foundation will be carried out.

2. Using the markings, use a shovel to dig a shallow trench measuring 50x70cm. We start digging from the lowest point of the terrain and then level the “horizon” of the entire trench. We make the walls strictly 45°. If the site mainly contains loose soil, then wooden supports can be installed.

   Trenches must be located in the locations of all walls, both external and internal

3. We lay geotextile fabric at the bottom of the trench, which will prevent soil particles from getting into the sand “cushion”. We lay it so that it extends beyond the edges of the finished trench.

   Geotextiles will provide drainage for the future shallow strip foundation

4. Pour sand into the bottom. The backfill is carried out in several layers, each of which is poured with plenty of water and compacted well. The height of the pillow should be about 20 cm.
5. We install formwork from plywood or unnecessary wooden boards. We knock them down with nails or twist them with self-tapping screws so that they do not go inside the boards, otherwise it will be difficult to disassemble it later. We make precise markings on the boards inside the formwork for subsequent pouring of concrete.

   The boards must be located above ground level

6. We lay the fittings inside. We saw off the rods to the size of the formwork walls and put them in a grid of reinforcement. We tie it with special wire. We tie all the corners and joints of the walls with reinforcement rods to maintain their strength during the movement of soil layers. If the height of the foundation structure is more than 30 cm, 2–3 rows of iron reinforcement should be laid. It is impossible to weld rods, since at the welding site there will be an area that is not resistant to rust, and the hardened metal will lose its strength.

   Reinforced formwork will give the base additional strength, reliability and resistance even to mechanical stress

7. We pour the bottom layer of concrete and carefully distribute it along the entire perimeter of the formwork, using a concrete vibrator, or simply pierce the solution with a rod to remove air. Pour the next layer after the previous one has set. We level the top layer of concrete according to the markings, smooth the surface with a flat board and sprinkle with dry cement. This is necessary for high-quality hardening of the solution and to prevent the occurrence of cracks during its drying.

   For pouring, either ready-made concrete mortar or one made independently from cement and sand can be used.

8. Depending on the weather, concrete can take up to 28 days to mature. After the solution has completely dried, you can begin laying foam concrete blocks.

To ensure a strong and high-quality foundation, you must follow the following recommendations:

Video: pouring a shallow strip foundation for a house made of foam concrete blocks

In the process of erecting any building from lightweight foam blocks, the main thing is to choose the right type of foundation so that the building can stand for many years without distortions or tilts. Compliance with rules, technologies and construction standards, as well as a well-developed design of a house made of foam blocks, is the main factor in the construction of any type of structure for this type of structure.

Instructions

Choose the foundation that is optimal for your conditions, taking into account all possible factors. Usually these are the characteristics of the soil, the number of floors of the future house, its size according to the project.

Check the composition of the soil intended for construction. If there is a large amount of clay, loam or peat, this means that the soil is very weak. In this case, arrange a columnar foundation for the house. Use it even if the soil is heaving.

Place reinforced concrete pillars in corners, in places where load-bearing walls will be erected, in areas of heavy load. Maintain a depth of at least a meter. Maintain a distance of one and a half to two meters between the pillars. Attach the reinforcement cage using tying wire to the mounting loops on the posts. The rods should be 8 mm in diameter, concrete grade M200.

Determine the depth at which groundwater is located. If their depth is more than three meters, a shallow strip foundation is perfect. It will require a trench 50 centimeters deep, which is dug along the perimeter of the future foam block structure and under the designed load-bearing walls. Arrange the base so that it is 10 centimeters wider than the walls. Place a cushion of crushed stone and sand on the bottom. Each layer should be 100 mm thick. Install the formwork and lay the two-layer reinforcement cage. For it, the rods must have a diameter of 10 mm. Concrete pouring will need to be done once, filling the entire trench at once.

If your site has a different type of soil, a monolithic slab foundation may be better than other options. It can be installed on any type of soil, except clay. Such a foundation is called floating - its design is such that the foundation can move along with the ground. At the same time, the walls of the future house made of foam blocks receive good protection from damage and cracks. You will need to build a pit under the entire area that the house will occupy according to the project. Its depth should be 60 cm. More than half of this will be used for the pillow - 25 cm of the pit should be occupied by a layer of sand, 15 cm by a layer of crushed stone. After this, install waterproofing and a frame made of reinforcement. It must be composed of two layers of reinforcement, the diameter of which is 8 mm; keep a step of 25 cm between the rods.

Video on the topic

note

If work is carried out in the summer, the concrete will dry out quickly, so its surface must be moistened and covered with film after it begins to set.

Helpful advice

In private buildings, a strip shallow foundation is considered to be the most suitable for the device - it can perfectly withstand the weight of the foam block structure. Its advantage is that it is possible to arrange a basement under the house, but it is not always possible to arrange this particular type of foundation due to the type of soil.

Tip 2: Which foundation is best for a foam block house?

For houses made of foam concrete, you need to choose a foundation that can stabilize any ground movement. This is important due to the characteristics of this material: hygroscopicity and tendency to crack.

Instructions

The main problem of houses made of foam block is the high hygroscopicity of this material. If this feature is not taken into account when choosing a foundation, there is a high risk of deformation, cracking and destruction of the blocks. Such buildings require a foundation with high-quality waterproofing, the base of which is located below the zone of ground movement. Compliance with these conditions will minimize the risk of deep cracks in the walls of the house.

Features of foundations for houses made of foam concrete

For buildings made of foam blocks, the optimal solution would be “floating” foundations. Such foundations are capable of absorbing even significant soil movements. Since houses made from this material are light in weight, you can opt for a shallow strip foundation. This is the most quickly erected foundation that does not require significant material and other costs. But it must be “floating”. That is, the height of the sand “cushion” under the sole of the tape should be increased from the standard 15-20 cm to 40-50 cm.

The correct arrangement of such backfill is as follows: sand should be laid in layers, with mandatory horizontal leveling using a hydraulic level. It is necessary to spray the “cushion” with water from a hose and thoroughly compact it with a vibrating plate, garden roller or some homemade device. Particular attention should be paid to the waterproofing of the foundation. Before starting to form the sand backfill in the trench, you need to lay sheets of roofing material so that its sheets are overlapped. It is recommended to coat the seams with bitumen.

After pouring the tape, the concrete must be protected from moisture: treated with bitumen mastics or covered with water-repellent material. A well-waterproofed foundation will serve as a reliable barrier to moisture penetration into the building. If groundwater in a construction area comes close to the soil surface, it is advisable to lay drainage pipes through which excess water will be drained outside the site.

Which foundation is better for houses made of foam concrete on moving soils?

For heaving soils, the optimal solution would be a columnar strip foundation. Supports should be installed below the freezing point of the soil. Under each of them there should be a sand “cushion” of appropriate thickness. Pillars “tied” with a grillage provide a more stable base that can minimize the impact of tensile and pushing forces that arise during soil freezing. This creates optimal conditions for comfortable operation of a house made of foam blocks.

When choosing a foundation for a house made of foam block, you need to pay attention to many factors - the groundwater level, the type of soil, the weight of the structure taking into account all the loads, as well as the depth of soil freezing.

Instructions

The stability of the foundation and the house built on it depends primarily on the condition of the soil. To determine the type of soil, it is best to hire qualified specialists who will take samples and prepare a conclusion. However, this procedure requires material costs, so few people resort to it.

You can independently drill several wells 2-2.5 m deep in the area and try to determine the type of soil. If the groundwater level is below 2 -2.5 m, the soil is considered to be slightly heaving, its freezing depth is no more than 1 m. As a rule, a monolithic strip of foam blocks is built on such soil; it is also possible to lay a shallow strip foundation.

When groundwater is located high enough, the soil is considered heaving. In this case, the construction of a strip foundation without appropriate drainage to remove moisture will be ineffective. Creating high-quality water drainage is fraught with significant material costs; the most suitable foundation for such soil would be a monolithic slab. It can be made as a slab foundation with stiffening ribs or in the form of an ordinary solid monolithic slab up to 0.4 m thick under the entire building.

Sometimes the top layers of soil are weak, but at a depth of 1.5-2.5 m there is strong and reliable soil. In this case, you can ignore heaving at such a depth and build a deep strip foundation with a base on dense layers of soil.

However, it should be taken into account that the strip foundation will be subject to lateral heaving forces that act tangentially on its walls. If a foam block house is light enough, lateral forces will be able to move it vertically. Such processes adversely affect the walls of the house.

Considering the light weight of foam blocks, it is recommended to build a pile columnar foundation on soft soils. The bases of the piles are laid in solid soil at a depth of 2-2.5 m. However, it should be borne in mind that this design is ideal for buildings with a small base that are minimally subject to deformation. When using a pile foundation for foam block houses, you should be careful, make accurate calculations and reduce the distance between the pillars to a minimum.

If it is impossible to do without a slab foundation, but its cost is too high for you, it is worth considering the option of constructing a slab foundation with stiffeners, this will slightly reduce costs.

Helpful advice

When constructing a strip foundation for a house made of foam blocks, try to make its walls as smooth as possible, this will reduce the effect of heaving forces. When using a columnar foundation, it is necessary to firmly connect the pillars using a strong monolithic grillage.

Sources:

• Build a house yourself, Foundation for a house made of foam blocks on various soils

The decision to choose a foundation for construction is influenced by many factors, including the type of soil and the load on the foundation. Foam blocks are a fairly popular building material with a cellular structure, characterized by lightness, strength and reliability. Building a house from such a material makes it possible to obtain a building with a small static load, so when designing, you can pay attention to lightweight foundation options.

Types of foundations for foam blocks

A heavy foundation for the construction of a building made of foam blocks will lead to unnecessary expenses that will not justify themselves. Therefore, already at the initial stage of building a house from such material, the benefits are quite obvious. Three types of foundations are considered the most suitable: strip, columnar and slab.

Each type is used depending on the structure of the soil, the value of its heaving, and the depth of groundwater. For example, if groundwater is located at a depth of three meters or more, a shallow strip foundation is suitable for a house made of foam blocks. Its difference is that the trenches for such a foundation go deep into the ground to a distance of 50 cm, so one person can dig such holes.

Strip foundation

Trenches 50 cm deep are located around the entire perimeter of the house and under the planned load-bearing walls. The base of the foundation must be made wider than the walls themselves by 100 mm; a cushion of sand and crushed stone should be laid at the bottom in 2 layers, the thickness of each of which is approximately 10 cm. Then the formwork is installed and a two-layer reinforcement frame is laid. Metal rods with a diameter of 10 mm are suitable for it. Concrete is poured into all trenches at once. To prevent concrete from drying out quickly in summer, its surface is watered and covered with a film after it begins to set. The hardening of the foundation continues for a month from the date of pouring. When building on a site with a high level of groundwater, the foundation is protected with waterproofing material.

Columnar foundation

A columnar foundation for a foam block house is used on soft soil, mainly consisting of peat, clay or loam. Also, this type of foundation for a house is used on heaving soil with a freezing depth of 1.5 m. The pillars for this type of foundation are made of reinforced concrete. They must be located under load-bearing walls, corners of facades and other places with heavy loads.

The depth of reinforced concrete pillars is equal to the depth of soil freezing, but it cannot be less than 1 meter. The distance between the pillars varies from 1.5 to 2 m. If the planned house consists of three floors, this type of foundation for foam blocks is usually reinforced with a reinforced concrete grillage. Formwork in a columnar base has a bottom supported by special supports that are installed in the ground. The reinforcement frame is attached to the mounting loops of the posts using a special knitting wire. Concrete grade M200 and rods with a diameter of 8 mm are used.

Slab foundation

A slab foundation for the construction of a foam block foundation is installed on any type of soil with the exception of clay. This type of foundation is called floating because of its ability to move along with the soil, preventing the walls of the house from collapsing. When constructing a floating base for foam blocks, a 60 cm pit is dug under the entire surface of the house. Of the entire depth of the pit, 40 cm is allocated for a cushion of sand and crushed stone, the thickness of the layers is 25 and 15 cm, respectively. After this, waterproofing is carried out and the frame is installed. It contains two layers of reinforcement with a diameter of 8 mm and a pitch of 25 cm between the rods. Such a foundation has great strength due to rigid reinforcement.

Results

The information presented above about the types of foundations gives a brief idea of ​​their characteristics, which allows you to make the optimal choice of the type of foundation, taking into account the structure of the local soil, the number of floors and the size of the foam block house itself. There are other types of bases, but they are used for heavier materials. As a rule, in private construction it is considered optimal to build a strip shallow foundation for a foam block house. One of its advantages is the ability to build a basement.

Foam block is a lightweight material, so such houses can be built on the simplest foundations: strip and columnar. The level of deepening of the base base depends on how close to the surface of the earth the groundwater lies and how far the soil freezes. If the TPG (soil freezing point) is below 1 m, and the GWL (groundwater level) is high, it means that during the freezing-thawing of the soil it will exert significant pressure on the foundation. Therefore, regardless of the type of base chosen, it will need to be buried below the TPG by 20-30 cm.

The simplest solution for a house made of foam blocks in regions with a warm climate and subject to stable soil is a columnar foundation. The supports can be built from ready-made factory products (reinforced concrete pillars or piles) or poured independently using asbestos-cement pipes as formwork. A columnar foundation can also be prefabricated: built from foundation building blocks (FBS). But this type of foundation will be more expensive, since the installation of reinforced concrete stones will require the use of lifting construction equipment.

Another type of foundation that is suitable for a house made of foam blocks is a columnar foundation with a grillage. It is a reinforced columnar base, the supports of which are connected by a concrete strip. Such a foundation is chosen in moving soil, and it is very convenient for those developers who want to make a basement with a separate entrance from the street.

If the terrain of the site is complex, with significant differences in elevation, the optimal choice is a foundation on screw piles. This base is also suitable for areas with marshy soil. Screw piles are mounted using a hole drill. The supports are buried below the TPG, so heaving forces will not have a negative impact on the foundation. Before installation, screw piles must be additionally treated with anti-corrosion compounds.

For a house made of foam blocks, high-quality waterproofing is very important. Therefore, any foundation of a building must repel moisture and prevent it from reaching the walls. If a strip foundation is being poured, its surface is covered with roofing felt; it is better to treat the pillars with bitumen or mastics. The same applies to reinforced concrete slabs. This type of foundation is chosen in the most difficult conditions, when only a “floating” monolith can provide immobility to the foundation: if the soil is unstable, the groundwater level is high, and the TPG is below 1.5 m. In this case, it is also necessary to install a drainage system: ring or wall drainage.

An important criterion for choosing the type of foundation for a house is the type of soil lying on the territory. Construction on clay often requires additional costs. One of the options for building a house on clay is to cut out all the bad soil and then fill the pit with draining soil and compaction.

This procedure requires a large amount of excavation work and entails an increase in construction costs. To increase the reliability of the foundation on clay, it is necessary to take additional measures.

Types of clay soils

Before you decide which type of foundation to choose, you need to know the type of underlying soil and its characteristics. For this purpose, engineering-geological surveys with laboratory soil tests are carried out. The geological report will describe which soils predominate in the construction area.

Sandy loam - soil with a clay content of 10 percent

The type of soil, its moisture content and the percentage of sand particles influence the choice of foundation. According to the regulatory literature, clay soil is divided into:

1. Clay. Here its content in pure form is more than 30%. This soil can be used for the foundation if it is homogeneous in composition and the freezing point of the ground is located above the groundwater layer. It is characterized by high flowability and plasticity.
2. Loam. It is sand with clay admixtures. Its content in the soil is no more than 30%. Loam is also divided into light, medium and heavy.
3. Sandy loam. Here the presence of clay does not exceed 10%. This type of soil is almost never used in construction, due to the high probability of its movement under the influence of groundwater.

Depending on the origin and location, glacial and alluvial clay are distinguished. Glacial soils are characterized by high bearing capacity compared to other soils of this type. If the layer is large and deep, it can be used under the base. As the depth decreases, the plasticity of the clay increases.

Alluvial type of clay soil predominates in lowlands, near water bodies. Due to its high plasticity, its use in construction is very limited. Such soil can float, which will lead to the appearance of cracks in the building.

Choosing a clay foundation

When choosing a foundation for a house, you need to determine the soils that lie on the construction site, as well as several very important parameters:

1. Soil water content.
2. The percentage of clay particles.
3. Ground water level.
4. The depth at which the soil freezes.

To find out the water level in the soil on a site, you can look into a well or do geotechnical surveys. Each region has its own freezing depth of the ground, so to determine this parameter it is necessary to use the regulatory literature and select it from the tables given in it.

Different types of foundations can be built on the same clay soil. The main criterion for choosing a foundation is the material of the walls, the number of storeys of the structure, and the presence of a basement. For buildings with a heavy load (wall material brick and concrete) on any type of soil (sandy loam, loam, clay) and the presence of a basement, a recessed strip foundation is used.

Types of bases

When the water level in the ground is below the freezing point of the soil, a monolithic strip foundation with an enlarged base is used. The support area becomes larger, which allows the pressure to be evenly distributed. It is necessary to drain water from the strip foundations by laying a sand cushion and drainage pipes.

Another option is a shallow strip foundation. This type of foundation is best used for lightweight wooden houses. The soil should contain a minimum amount of clay particles and the groundwater level should be below the base. This is tied into a rigid structure to distribute the impact of the soil along the entire length of the tape. With this option, large bending forces arise, so two reinforcing belts are installed. The shallow strip base is a general floating system that is immune to minor soil disturbances. Watch a video of how a strip foundation is built on clay.

If there is high pressure from the future house, the presence of heaving soils and low groundwater levels, a slab foundation is chosen. In most cases it is expensive, but also the most sustainable. This type of foundation is a floating slab on which a large house can be built. It is possible to make a floating slab in the form of a concrete strip.

Well suited for construction on clay. The load from the house is evenly distributed, and when the ground erodes or shifts, the entire slab will shift completely. The floating slab is not placed deep, but must be placed on a sand and gravel bed.

If groundwater is located close to the surface of the earth, then it is better to use a pile foundation on clay. Piles are driven or screwed to the depth of hard rock. Supporting the piles on dense rocks ensures the stability of the foundation, and therefore the building as a whole. It is worth remembering that if the choice fell on this type of foundation, then the owner of the house will have to build the house without a basement.

To fix the piles, they are tied with a beam or channel. Timber is used for wooden houses, the walls of which are made of logs or timber. If the walls are brick or foam concrete, then use channels. A special head is put on the piles, and the timber is tied using holes in it.

Not everyone decides to choose a floating columnar foundation for a building on clay. It can only be used for wooden houses. Instead of a monolithic structure, FBS blocks or masonry from wall blocks are used. Due to the small supporting surface of the log, the lower crowns of the log house are made of timber, reducing the pitch of the pillars, preventing the wood from collapsing. For this configuration, both a floating slab and a concrete strip are used. Watch the video on how to build a concrete slab on clay.

The construction of houses from foam blocks has become widespread. It can be classified as a lightweight material with minimal pressure on the soil compared to brick or concrete. For houses made of foam blocks, shallow strip and pile foundations are used.

Causes of foundation deformations and measures to prevent them

When building a house on clay, you should be aware of their features. Depending on the type of clay, the content of sand particles reaches a minimum of 5%. Under the influence of groundwater, sand can be washed out, which will lead to subsidence, heaving and plasticity.

The most common causes of damage to building foundations due to clay:

1. House subsidence. When the sand component is washed away by groundwater, cavities appear, which leads to subsidence of the house. This is typical when groundwater is located high and there is high pressure on the foundation.
2. Heaving. It appears when building a foundation above the freezing level of the soil, which contains loam or water-saturated clay. When water freezes, it increases in size and affects the base from below.
3. Impacts on the foundation from the side. The deeper it is, the higher the load. Clay, due to its plasticity, acts on the base from the side, which entails the possibility of cracks or splits.

To take into account the influence of the earth from below, it is necessary to lay a reinforcement cage throughout the entire volume, which connects the top and bottom of the base.

To minimize lateral impact, the sole of the base is made wider than the top. For waterproofing, it is advisable to cover the sides with machine oil or wrap the base with film. When the area of ​​the base decreases on the side, the effect of forces during soil heaving decreases.

The depth of soil freezing can be reduced to a lesser extent by insulating the soil with special materials around the building.