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Correctly choosing and building a foundation that is optimal for a certain type and size of a house means providing the building with solid support that will last for several decades. Even a structure designed by a genius will not last even a couple of years if it is installed on an unreliable foundation. Groundwater, seasonal precipitation, changes in soil density and mobility will quickly destroy such a building.
It is advisable to shift the care of choosing and equipping a foundation to professionals who have the proper experience and know how to build a foundation for a house. This will not lead to budget overruns, installation errors and, as a consequence, poor quality of support. Qualified specialists will not only help you decide on the type of optimal foundation, which will reduce the overall costs of building a house, but are also guaranteed to do the work to the highest possible quality.
Sectional view of the foundation
Types of foundations for low-rise construction
Choosing a suitable foundation for a house is the main task with which construction begins. The wrong type will affect the durability of the building, strength characteristics or cause unnecessary costs. Therefore, you should first decide on the type of support. To do this, a number of important parameters are taken into account.
- Depth of groundwater. If they are too close to the surface, an inadequate foundation will lead to flooding and uneven settlement of the building.
- Soil density and composition. Movable soils require one type of foundation, dense soils require another.
- Depth of ground freezing. If you do not take this factor into account, then after each thaw there is a chance of cracks forming in the foundation, walls and ceilings.
Reinforced strip foundation with ventilation holes
In low-rise construction of residential buildings, cottages, bathhouses, sheds and other outbuildings, four main types of foundations are used.
- Tape. It is a continuous structure, which is located along the perimeter of the future building. It can be poured into formwork directly on site or assembled from concrete blocks made separately.
- Slab. It consists of several layers, each of which performs a specific function. The top layer is a solid reinforced concrete slab.
- Pile-grillage. It is assembled from pillars buried deep in the ground, which are connected at the top by a grillage-lintel that evenly distributes the load on the structure.
- Pile. It is erected from supports that are located evenly under the entire area of the house or under places with the greatest load - corners of the house, walls, lintels.
Depending on the above factors, the building material and its dimensions, the final result is determined and a foundation project for the house is created.
Sectional columnar foundation
Columnar foundation for light outbuildings
When building any foundation, the weight of the building must be taken into account. Lightweight outbuildings do not require a monumental foundation, so columnar foundations are most widely used for them. Their choice is due to the following qualities:
- speed of installation;
- low cost;
- ability to provide reliable support.
The columnar foundation is installed on a cushion of sand or fine gravel; in the upper part, the pillars are connected by beams, on which the base will be installed in the future. It is important to take into account the depth of soil freezing and the degree of heaving. This type of foundation is suitable for low-moving soil, otherwise the structure may shift.
Columnar foundation
On our website you can find contacts of construction companies that offer foundation design and repair services. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.
Pile foundation for frame houses
A pile foundation is several piles screwed or driven into the ground (thick metal pipes with an anti-corrosion coating), on which the piping is mounted and the house is built.
Video description
What are the features of concrete driven piles? We'll talk about pile foundations in our video:
Since this technology is relatively new and not all construction companies can boast that they master it perfectly, there are still cases when, some time after construction, a house sags somewhat under some piles. But foreign experience shows that such incidents occur only when the technology is not followed, and if the installation of a pile foundation is carried out according to all the rules, then it will become a reliable support for the house. In addition, piles allow the construction of buildings even on soils with a high degree of mobility.
Foundation for wooden houses made of logs
Buildings made of rounded logs and beams have less weight than brick or concrete, but exceed frame houses, so the best option for them would be a shallow strip or pile-grillage foundation.
The first option allows you to equip a basement, has sufficient resistance to loads and is relatively low cost. To ensure its durability, it is necessary to equip it with high-quality waterproofing and pour a thick sand cushion.
For a pile-grillage foundation, you need to dig holes to the level of soil freezing and connect them with isthmuses. Then concrete is poured into the pits and ditches and a concrete strip is obtained, from which pillars emerge, resting on the soil below the freezing level.
Construction of a pile-grillage foundation
These types of foundations provide the opportunity to equip a reliable and durable foundation that can easily support the weight of a wooden house of one or two floors and will allow you to avoid unnecessary overpayment by equipping an unnecessarily expensive support designed for an impressive mass.
Slab and strip foundations for stone houses
Buildings made of brick, concrete or building blocks require a strong foundation because they have an impressive weight and are completely devoid of plasticity, which, although to a small extent, is inherent in wooden houses. The slightest movement of the base can lead to the formation of cracks in the walls and ceilings. Therefore, the best option would be a slab or buried strip foundation.
Multilayer slab foundation
The slab base is a multi-level structure that fits into a pre-dug hole, slightly larger than the size of the building under construction. Pcastfoundation for the home consists of the following layers:
- crushed stone cushion;
- layer of sand;
- waterproofing;
- reinforced concrete slab;
- second layer of waterproofing;
- insulation.
This type of foundation allows you to withstand the heavy weight of the building and provides stationary support on heaving soils.
Strip foundation deep laying is mounted at a depth of more than a meter in order to be below the soil freezing level. Depending on the region and average annual temperature, this value may vary. The strip type of base performs a double function; in addition to providing reliable support for stone walls, it allows you to equip a basement, but in this case you will need to spend money on waterproofing and insulation.
Deep strip foundation
Online foundation calculator
To find out the approximate cost of various types of foundations, use the following calculator:
Which foundation for a house will cost less?
When considering how to properly build a foundation for a private house and not spend more than necessary, you should take into account the type of soil, the weight of the structure and a lot of other characteristics, then you will be able to choose the ideal option.
- The lowest cost and time required are inherent in a columnar foundation. But it has two significant limitations: installation only on low-moving or stationary soils and the low weight of the structure. As a result, it is categorically unsuitable for a residential building or heavy construction.
- In second place are piles, but here everything depends on their type. Screw ones are the most inexpensive of all but are suitable for light buildings, bored ones are for brick and concrete, and driven ones provide a high level of stability, but are very expensive.
- Strip foundation. The non-recessed and shallow-depth type will not cost much more than the columnar type, and the deep-laying tape has the highest price due to the increased volume of work and the use of a large number of materials.
- A monolithic slab is the most expensive type of foundation, but provides maximum reliability on heaving soils. In some cases, such a foundation is the only option suitable for the soil.
Video description
What types of foundation are there? How is the foundation built and how much does it cost? See all this and much more in this issue:
As a result, it is far from a fact that a seemingly inexpensive foundation will remain so. Sometimes it happens, for example, that it is more profitable to make a monolithic foundation than to bury a strip foundation to the freezing depth. The choice of foundation should be based on a combination of factors because the price may change depending on the situation.
Slab foundation with bitumen coating for a brick house
Strip foundation - the best option
If the soil does not impose any special restrictions on the choice of foundation, then a strip foundation will be the best option. Its advantages compared to others:
- ensures high stability of a building of any weight;
- universal (depending on the situation, a certain type of foundation is used, which allows you to spend the budget within strictly defined limits);
- arrangement of hydro- and thermal insulation ensures resistance to soil freezing, protects against the formation of condensation and extends the service life of the support.
The only limitation for installing a strip foundation is high soil moisture, but there are few areas with such soils in our country, so in all other cases this type of foundation can be used.
Ready-made shallow strip foundation
Conclusion
The foundation is one of the most important parts of a building. It is stupid to save on it, it cannot be made of low quality, access to it will be greatly limited after the building is built, which complicates repairs. His equipment must be done immediately and well, so such work can only be trusted to professionals.
Foundations on screw piles have many advantages, one of which is the speed of foundation construction and ease of installation.
This article will give an example of calculating the required number of piles for the foundation, as well as the procedure for installing screw supports.
Types of insulation
There is a large selection of insulating materials on the market. Sometimes it can be difficult to understand all this diversity. Some types of insulation are ideal for walls, but absolutely not suitable for foundations.
This article will discuss various types of insulation and provide recommendations for use.
Ventilation holes in the foundation
At the stage of laying the foundation, do not forget about such an important point as ventilation holes or as they are often called vents or vents.
They are necessary to reduce humidity in underground and basement spaces.
Why this is needed, what size the vents should be, how many ventilation holes are needed, we will tell you in this article.
Why insulate the foundation of a house? How to do this correctly?
Insulation of the foundation is one of the most important stages of construction. Insulation protects the base from destruction and makes the temperature in the basement more comfortable.
How to properly insulate a foundation, what materials are best suited for these purposes, how thick the insulation should be and how to calculate it - you will get the answer to these and many other questions by reading this article.
Installation of insulated blind area
An insulated blind area will not only protect the foundation from various precipitation, it will also help retain a significant part of the heat in the house, helping the heat to remain indoors.
In this article we will look at several options for insulated blind areas and their design for various foundations. We will also advise what material to use for insulation and what brand of concrete to pour.
Construction of a slab foundation for a house
A slab foundation is one of the universal foundations that can be laid on any type of soil and at high groundwater levels.
The main advantage of such a foundation is its high load-bearing capacity. This is achieved due to the large area of the slab.
This article will consider the construction of the foundation, in the form of a monolithic insulated reinforced concrete slab, which was laid under a small house made of aerated concrete.
Strip foundations are characterized by the same cross-sectional shape along the entire perimeter of the house. Despite the high consumption of materials, significant labor intensity and a large volume of excavation work, thanks to simple technology this type of foundation is widespread in individual construction.
Types of strip foundations
According to construction technology, there are 2 types of strip foundations for a house:
- monolithic - a continuous reinforced concrete strip reinforced with a steel rod structure;
- prefabricated - from factory-made blocks (brick, reinforced concrete blocks) or rubble stone.
General diagram of the construction of this type of foundation for a house:
- earthworks - digging a trench;
- installation of formwork – removable, non-removable;
- pouring concrete mortar or laying individual elements with mandatory reinforcement;
- dismantling of formwork, moisture protection.
To do the right thing for your home, it is better to involve professionals in its design. Based on geodetic studies of the soil, technical characteristics of the house and climatic conditions, specialists will prepare the necessary design documentation, including an estimate of construction work. The costs of services are fully recouped - savings in materials, time, and no problems during operation.
In the case of independent planning, it is necessary to study the relevant GOSTs and SNiPs: for example, SP 70.13330.2012 indicates not only how to select building materials.
The advice of “experienced people” and the experience of neighbors can be taken into account, but only if the house on a foundation built using the recommended technology has been in operation for at least 5-10 years.
When planning work, all stages of construction, as well as related activities, should be considered in detail:
- transportation and storage of building materials, equipment, tools;
- organizing the access of special equipment and garbage removal.
It is necessary to take into account the possibility of changing weather conditions.
The choice of a specific technology depends on the design of the house and the available construction equipment.
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Territory marking
If you plan to make a foundation for a small house, you will need:
- pegs;
- cord;
- roulette;
- rectangle - you can make it yourself.
First, the location of the first corner of the house is marked and a line is drawn perpendicularly from it to the second, and a cord is pulled over the pegs. Then the second and third corners are also outlined. A regular rectangle has equal diagonals.
Having retreated from the external markings by the width of the foundation, you need to make internal markings.
To build large foundations, it is better to use a level (you can rent it).
At the same time, an area is marked out for storing building materials, installing a concrete mixer, and communication lines (water supply, drainage).
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Excavation
You can dig a trench for the foundation by hand or with an excavator. The first option is suitable if you plan to build a small wooden house on a shallow foundation or if there are no access roads to the construction site for specialized equipment.
First, the entire site is cleared of vegetation: bushes and trees are uprooted, and the top fertile layer of soil is removed. Soil stability and the depth of groundwater are of great importance. When clayey, silty and sandy soils are watered, their load-bearing properties are significantly lost. for a house can turn into underwater concreting if water enters the trench through a cut waterproof layer or from an underground source.
Clay soil can settle over several years, and the volume of porous organic soil (peat) decreases greatly when drained. Therefore, before starting work, you should assess the distance to the nearest buildings and, while digging a trench, organize monitoring of the stability of their structures and soil in the surrounding areas.
The depth of the trench is the depth of the foundation plus the thickness of the gravel-sand cushion. The count should start from the lowest point on the surface.
When planning the operation of a basement, for example for storing winter supplies, in some cases it is more convenient to excavate the soil before making the foundation.
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Preparing the trench
Preparing a trench for pouring concrete or laying individual elements is practically the same.
The slopes and bottom are leveled using plumbs and a building level. The shortages are removed, and the excesses are replenished with crushed stone, sand, and a gravel-sand mixture. The bottom is compacted using mechanical or manual tampers. Next, the pillow is placed under the foundation:
- geotextiles prevent mixing of the sand layer with the soil and siltation of the cushion when the groundwater level rises;
- sand – coarse or a mixture of coarse and medium coarse;
- gravel, crushed stone – fraction 20-70 mm;
- a layer of concrete about 5-7 cm - waterproofing.
The thickness of the sand layer is from 20 cm to 3/1 relative to the width of the shallow foundation. Sand is compacted by pouring water and compacting. When walking on a sandy surface, there should be no traces left. Carefully leveled.
The thickness of the crushed stone layer is about 20-30 cm. It is leveled, compacted (rolled, rammed).
The concrete layer should mature in 10-15 days, then it is coated with bitumen and covered with roofing felt.
After this, the formwork is installed:
- removable - any sheet materials or construction formwork for foundations (can be rented);
- non-removable - blocks made of factory-made extruded polystyrene foam.
The further course of work is determined depending on the chosen type of foundation - monolithic or prefabricated.
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Monolithic foundation
When building a house, the next stage is reinforcement.
The reinforcing structure can be installed directly in the trench or in blocks on the ground surface. The connection of reinforcement elements is carried out by welding and wire bonding. In the first case, it is necessary to purchase a reinforcing bar, the marking of which contains the letter “C” - weldable. Unified standard welded mesh can be used.
Before starting work, all metal elements are cleaned of dirt and rust. It is prohibited to make the foundation of a house using scrap iron as reinforcement.
The thickness of the protective concrete layer for the reinforcement frame must be at least 40 mm on all sides. Typically, a metal system consists of 2 vertical rows connected to horizontal ones: the number is determined by the depth of the foundation. The step for installing the reinforcing bar is from 10 to 25 cm:
- vertical rods – smooth or ribbed, diameter from 10 mm;
- transverse reinforcement – smooth or ribbed rod, diameter from 10 mm;
- longitudinal rods – ribbed, diameter from 12 mm
The maximum number of errors when reinforcing monolithic foundations for a house is allowed at junctions and corners. Simply crossing the rebar in these areas is not enough! In practice, this is a rupture of the reinforcement, the result is the formation of cracks at the corners and delamination of the monolith.
The correct options for laying the reinforcing bar are shown in Figures 1 and 2.
In the conditions of a construction site, it is difficult to comply with all the requirements for the composition of the concrete mixture and the technology for its preparation. It is better to make a foundation using factory-made mortar.
When preparing concrete yourself, you must follow several rules:
- use only clean sand and crushed stone of fractions 1.2-3.5 cm and 1-8 cm, respectively;
- the ratio of cement, sand, crushed stone is 1/3/5.
First, the dry ingredients are mixed, then water is added to them. The addition of plasticizers will provide the concrete with the necessary fluidity, which will greatly facilitate the work. Manufacturers usually indicate instructions for using the additive on the packaging. The use of household chemicals as plasticizers is unacceptable!
Concrete is poured into the trench in horizontal layers with mandatory compaction of each layer. If necessary, the foundation can be poured in parts. To ensure tight adhesion of the new layer to the already set concrete base, the following is required:
- clean it of debris and dirt;
- remove the surface layer of cement laitance with an iron brush or other available means;
- remove dust from the surface.
Filling ends at a level of 50-70 mm from the top edge of the formwork. Until fully matured, the concrete is protected from moisture (from rain) and from losses: it is covered with polyethylene and wetted. The minimum ripening period is 28 days.
The most popular type of foundation in private construction is considered to be a strip foundation. This is due not only to its excellent technical characteristics (high load-bearing capacity, mechanical strength, reliability, durability, etc.), but also to its much lower cost compared to other types of foundations for low-rise buildings. Another significant advantage of such structures is that you can build them yourself, saving a certain amount of money on the services of a construction team. Let's look at building a strip foundation with your own hands - step-by-step instructions, photos and diagrams.
Design and types of strip foundations
The strip base is a reinforced concrete strip of a certain thickness and height, which is installed along the perimeter of the future building, as well as under all internal walls (Fig. 1). The poured foundation is made from a concrete mixture of grade B22.5, for mixing which M200 cement, coarse sand and gravel are used in a ratio of 1: 2: 2.5, respectively. To give the structure the required strength and reliability, reinforcement is made along the entire perimeter with steel rods with a diameter of 8-12 mm (Fig. 2).
When planning to build a private house with your own hands, you need to take a responsible approach to choosing the type of strip foundation.
The following parameters are taken into account:
- expected loads on the future foundation;
- soil characteristics at the construction site;
- groundwater level;
- freezing depth.
According to the type of connection between concrete and soil, strip foundations are divided into:
- shallow;
- deep;
- pile-tape.
The first type is used in the construction of one-story buildings on stable soils. Shallow foundations– an ideal solution in terms of price and quality when building a log house. The main feature of such foundations is that they are located much above the soil freezing level. The advantages of shallow foundations include their low cost and ease of excavation work. The disadvantage is that it cannot be used on many soils and for the construction of two-story buildings.
Deep foundations are considered more durable and reliable, since they are not subject to seasonal swelling. However, filling them requires more time, effort and money. Such foundations are perfect for the construction of large brick houses.
When choosing the depth of the strip foundation, take into account the nature of the soil at the construction site. On heaving soil, it is recommended to use a pile-strip foundation.
Pile-strip foundations In addition to reinforced concrete strips, they are additionally equipped with screw, bored or driven piles. This design makes it possible to improve the mechanical properties of the base and increase its adhesion to the ground. This type is the optimal solution for private construction on heaving soil.
Stages of construction of a strip foundation
The entire process of creating a strip foundation can be divided into several stages:
- marking the work site;
- excavation;
- formwork design;
- reinforcement;
- pouring concrete.
Marking the site and digging a trench
Before proceeding directly to pouring the base, it is necessary to properly prepare the work site. It is cleared of trees, roots, bushes, large stones and other obstacles. Then, according to the existing house plan, markings for the foundation are applied to the site using stakes and a cord. The marking of the work area should be done carefully, since even small deviations from the plan can lead to distortion of the future structure, additional costs and other unpleasant moments.
If the work site is level, then there should be no difficulties with marking. If you have difficult terrain, it is advisable to have a laser level on hand. Be careful when marking corners, they must be strictly straight.
Once the markings are completed, you can begin excavation work. Digging a trench is done manually or with the help of heavy equipment. It all depends on your budget.
When choosing the width of the tape, you should take into account the type of future structure and soil characteristics. Thus, for the construction of a bathhouse or utility building on solid ground, the minimum permissible foundation width is 25 cm, and for silty or sandy soil - 50 cm. For the construction of one-story houses, it is necessary to pour a strip foundation with a width of at least 40 cm for hard soil and more than 80 cm for silty soils.
If you plan to make a shallow foundation, then the depth of the trench should be about 60 cm. The depth of a deep foundation is selected 25-35 cm more for the depth of soil freezing. At the same time, it is allowed to build a foundation of less depth under internal walls and partitions.
After the trench is dug, its bottom and walls are checked for horizontal and vertical evenness using a building level. Next, a gravel or sand cushion is installed at the bottom of the pit and carefully compacted.
The recommended thickness of this ball is 15-20 cm. A ball of waterproofing material (thick polyethylene film, roofing felt, etc.) is placed on top of the pillow. This helps protect the foundation from groundwater and reduce the loss of moisture from the concrete during setting.
Formwork for strip foundations
The formwork for a strip foundation (photo above) can be assembled from boards more than 4 cm thick, as well as from wooden, metal panels or polystyrene foam boards. Which formwork option to choose depends only on you. To fasten the boards together, wooden beams with a cross-section of 5 cm are used. Screws or nails must be screwed in from the inside of the structure so that the heads are recessed into the wood.
To give the formwork the required rigidity, the walls from the outside are additionally fixed with supports, and between themselves - with vertical jumpers in increments of 50-100 cm (Fig. 3). To prevent concrete from penetrating through the cracks between the boards, the inside of the formwork is covered with a layer of waterproofing material. The formwork should be 0.3-0.4 m above ground level. The above-ground part will be the base of the house. When assembling the formwork, you need to immediately cut holes in the boards and lay drain pipes, since this will be difficult to do after pouring the concrete.
Reinforcement and pouring of concrete
Reinforcement of a strip foundation is a mandatory procedure, the correct implementation of which determines the strength characteristics of the entire structure. Metal rods 8-12 mm thick are used as reinforcement. They are cut into pieces of the required length and laid along and across the foundation. If the depth of the base is more than 40 cm, then the rods must also be mounted vertically (Fig. 4).
It is not recommended to use welding to connect reinforcement, because such connections are hotbeds of corrosion.
The rods are attached to the formwork and connected to each other with steel wire. It is not recommended to use a welded connection, as this will eventually lead to corrosion of the metal and deterioration of the mechanical properties of the base. After the reinforcement is finished, you can begin mixing and pouring the concrete solution. To remove bubbles from it, use a vibrating machine or compact the poured mixture with a wooden block. The top layer of the mixture is leveled with a rule or trowel.
10-15 days after completion of the work, the wooden formwork is dismantled, after which the outer walls of the foundation are treated with liquid or film waterproofing. This will protect the foundation from the destructive effects of groundwater. At the last stage of the work, backfilling is carried out using sand.
Features of a do-it-yourself pile-strip foundation
Pile-strip foundation is one of the types of strip foundation. It consists of a continuous shallow structure, on which the walls of the building rest during operation, and piles installed in the ground below the freezing depth (Fig. 5). This design allows not only to reduce the cost of building a foundation, but also to increase its adhesion to the ground.
Below is a step-by-step instruction for a do-it-yourself pile-strip foundation:
- Site preparation. As in the case of a strip-type reinforced concrete foundation, the construction site is cleared of debris, leveled and marked.
- Land works. A trench is dug under the tape up to 50 cm deep. The bottom of the trench is filled with gravel or sand and compacted. Then, holes for piles are drilled in the corners of the future structure, at the junctions of the walls and every 200 cm. The depth of the wells should be 30-40 cm greater than the freezing depth. The cross-section of the holes is chosen so that the piles fit into them without much effort.
- Installation of piles. Metal or asbestos-cement pipes are installed in the prepared wells, after which they are reinforced and concrete mixture is poured into them.
- Formwork design, reinforcement and concrete pouring. This stage is performed in almost the same way as for the strip base. The only difference is that the reinforcement of the piles is necessarily connected to the reinforcement of the grillage.
To make the foundation correctly, you need to carefully study the options for construction types and their features. The construction of the underground part is carried out taking into account the following requirements:
- economic expediency;
- reliability;
- strength;
- durability;
- sustainability.
Before starting construction work, a soil study should be carried out. The choice of the right type of foundation is influenced by the total weight of the house, the strength of the soil and the groundwater level. A foundation that is carefully made and built in compliance with technology will last a long time and will not cause problems during operation.
Preparatory stage
It’s worth starting with pits or drilling. The main goal of this activity is to find out what soils are located on the site, as well as to find out the level of groundwater. The foundation must be laid in compliance with the rule: the mark of the sole must be at least 50 cm above the level of the water horizon.
How to do soil testing correctly? Two methods are used for this:
- excerpts of pits (deep holes, dimensions in plan are usually 1x2 m);
- manual drilling.
In the first case, the soil on the walls of the pit is examined. They also check to see if water has left the bottom. In the second option, the soil on the tool blades is examined.
Once you have determined what kind of soil is on the site, you will need to find its strength indicators. This can be done using special tables.
The cost of laying the foundation for a house can be up to 30% of the estimate for the entire building. To avoid cost overruns, you need to perform a calculation that will allow you to find the optimal design parameters that will simultaneously guarantee minimum costs, strength and reliability. For your convenience, you can use online payment.
Types of foundations
Building a foundation with your own hands involves the use of several technologies:
- ribbon;
- combined options.
Columnar supports have a low load-bearing capacity. It is possible to install monolithic pillars or assemble them into compact concrete blocks. Both options are great for DIY projects.
There are three types of pile foundation for a house:
- driven (not recommended for private buildings due to the need to attract equipment);
- (suitable for building a brick or concrete house);
- (ideal for light wooden buildings).
Piles make it possible to reduce the amount of excavation work. There is no need to dig trenches or a foundation pit or transport large amounts of soil outside the site. Thanks to this quality, installing this type of foundation is a very economical choice. The main disadvantage will be the impossibility of equipping a basement or underground for utilities. In this case, the base of the building is covered with decorative materials.
Another advantage of piles is the possibility of using them in wetlands. Even if the groundwater level is located close to the ground surface, the supports provide the necessary load-bearing capacity.
The next option is tape. It can be made monolithic or from blocks. The second option is rational to use for mass construction. Strip foundations are:
- recessed (for buildings with a basement, brick and concrete structures);
- (for wooden and frame houses);
- non-buried (technology of pouring foundations for small buildings on a solid foundation).
Before making a tape, it is worth checking the groundwater level and compliance with the rule that the sole cannot be closer than 50 cm to the groundwater horizon. Otherwise, there is a high probability of flooding of the basement, reducing the load-bearing capacity of the foundation and destruction of the materials of the supporting part of the building.
What to do with high groundwater level? If the structure is made independently from brick or stone, screw piles will not be suitable, and for bored piles it will be necessary to lower the water level. An excellent option would be filling. In this case, a non-recessed or slightly recessed base is made. The thickness of the slab is determined depending on the load, on average 300-400 mm.
How to pour a foundation for a house
Monolithic foundation type is the best option for private housing construction. In this case, laying can significantly save on transportation and installation of structures. There is no need to hire a crane to install elements in the designed position or a KamAZ truck to transport concrete blocks and slabs.
Monolithic foundations can be made from factory-made concrete or you can mix the solution yourself using a concrete mixer. The first option is recommended. The fact is that it is very difficult to strictly observe the proportions of the composition in artisanal conditions. For factory-mixed concrete, such a guarantor will be a passport, which indicates the verified indicators of the material.
To make the material yourself, you will need to prepare clean water, cement, sand and crushed stone (or gravel). They are mixed with each other strictly observing proportions, which depend on what grade of concrete needs to be obtained. If you add a little more sand or crushed stone to the composition than required, the strength of the supporting part of the building will suffer.
To properly pour the foundation, you need to familiarize yourself with the basic rules of concreting:
- Concrete must be poured in one go at time intervals of up to 1.5 hours. If you take long breaks in work, the solution sets and concreting joints form, which weaken the structure. The technology allows making horizontal seams if absolutely necessary. It is unacceptable to install vertical seams on a monolithic foundation, since in this case the support of the house will not be able to resist soil deformations.
- The class of concrete is chosen depending on the type of supporting part. For a columnar or pile foundation, class B 15 is sufficient. For tape, grades from B 15 to B 22.5 are needed. Construction of a house foundation using slab technology requires concrete grades B 22.5 or B 25.
- After pouring, the material should gain strength. On average, this takes 28 days. Construction work can continue after the structure reaches 70% of its original strength.
- It is better to carry out work in warm, dry weather. The ideal average daily temperature for concrete hardening is +25°C. At temperatures below +5°C the material practically does not harden. For normal hardening in this case, special additives and heating are used.
- The concrete must be maintained within 1-2 weeks after pouring. It involves wetting the surface with water.
- To mix the mixture yourself, you will need cement, sand, crushed stone (gravel) and clean water. The proportions depend on the strength class. The material is delivered from the factory using a concrete mixer truck - it allows you to extend the life of the solution and deliver it over relatively long distances.
How to pour the foundation correctly? In general, work is performed in this order:
- installation of formwork and reinforcement cage;
- laying waterproofing material in formwork;
- pouring concrete;
- its compaction by vibration or bayonet;
- curing;
- stripping works (if necessary).
To quickly complete the work, it is recommended to order a concrete pump together with a concrete mixer. Concrete manufacturers are usually willing to provide this technique. In this case, it is necessary to use a concrete mixture of grades P3 or P4 in terms of mobility. Otherwise, the equipment breaks down.
Step-by-step instructions for pouring a strip foundation
Concreting is considered using the example of a monolithic tape. To erect the supporting part of the structure, construction is necessary. To do this, use cast-offs and construction cord. You need to show the edges of the tape.
After marking, the soil is excavated. If there is no basement, it is enough to dig a trench. At its bottom you need to make a sand cushion. It performs several functions:
- ground leveling;
- prevention of frost heaving;
The edges of the trench must go exactly along the cord Next stage - . For this purpose, the material included in the estimate is used: boards (removable type) or polystyrene foam (non-removable). The second option serves not only as a form for pouring concrete, but also as insulation of the underground part of the building. When installing the formwork, I raise the base to the desired height.
