What is a strip foundation? A properly calculated and installed foundation of the structure is the key to a safe and high-quality construction for any building. There are several varieties of the foundation at once, but the tape is considered the most popular and convenient to operate. To create it, you do not need to use additional devices. Anyone can recreate the tape foundation with their own hands, and step-by-step instructions will help to deal with this issue quickly and easily.
The main pros and cons
What is a strip foundation? Why is he called that? The strip foundation for the house got its name because of the reinforced concrete tape at the base, which is buried in the soil at a certain depth. The external and internal walls of the building throughout the lower cavity rest on the surface of such a tape. By the type of penetration into the ground, the strip foundation can be buried (from 1.45 to 1.65 meters), as well as with shallow burial (not more than 1.4 meters).
The first variety is used, as a rule, for large buildings and high-rise buildings, and the second - for the construction of low-rise buildings. In its structure, the foundation can be precast and monolithic. Monolithic is poured with a special concrete solution, and the precast is created from separate reinforced concrete blocks.
To create a monolithic correct strip foundation, the following types of materials are used:
- sand;
- crushed stone;
- water
- broken brick;
- Portland cement;
- shrapnel rock;
- steel reinforcement.
With an independent erection of the structure, you can contact the construction company and order a turnkey strip foundation.
Main advantages
Now it’s clear what a strip foundation is? It has a large number of advantages that make such a device truly popular among other types of bases:
- minimal susceptibility to high loads;
- simple creation without the use of heavy technical devices;
- fortress of the finished structure;
- when using such a foundation, it is possible to build on soil mixtures of a heterogeneous density;
- construction walls can play the role of walls in the basement of a house.
The small width of the strip foundation is an additional advantage of such a basis.
It is important to remember that such a system has its drawbacks:
- construction requires the use of a large number of materials;
- without fail you need to carry out waterproofing on the site.
What is a strip foundation? With all its pros and cons, this type of foundation is considered widespread, especially when built in the private sector.
To correctly calculate the strip foundation, you should use a special calculator for calculating concrete. In such a calculator, you just need to enter the parameters of the trench to get as much information as possible about the amount of required materials. Also, using such a device, you can easily determine the entire cost of the foundation.
DIY creation
How to make a strip foundation? Due to the fact that to create such an object it is not necessary to use heavy technical equipment, anyone can easily build it on their own.
For this, a special step-by-step instruction will be presented below. The strip foundation can be erected by any man with minimal skills in construction.
Site preparation
Before you start creating a foundation, it is important to carefully plan the site and mark the axes. Planning means alignment of the site along the entire perimeter and construction in height.
If there are strong elevations in the territory, then it is important to take this into account when digging a trench. In higher areas, digging will have to be much deeper, but in the lowlands, the height of the foundation will be greater.
The layout of the slabs of the strip foundation is carried out by means of a special triangle with sides 3: 4: 5. The angles in this case should be straight, and all diagonals equal.
Earthworks
After the preparation of the site and careful planning, digging of the trench to the desired depth begins along certain marking axes. Its depth will directly depend on the density of the soil, the total distance to groundwater, and the weight of the future building. For a house with a large number of floors, 1.5 meters are used, for a private building only one meter is enough, if the soil allows.
At the end of digging a trench at its bottom, it is necessary to ram the soil and drain it with layers of rubble and sand. This layer is also called a pillow. The width of the resulting trench will directly depend on the material from which the walls will be created. For private construction, a width of 60 centimeters is enough.
Do-it-yourself formwork
After the trench is finished, the construction of the formwork begins. Some construction companies have reusable precast formwork, which is very simple and comfortable to use. Also, such a formwork for a strip foundation can be easily created with your own hands. To do this, prepare bars and tes. Their number will depend on the scale of construction.
The formwork is a wooden box installed above the trench. Since a liquid solution will be poured into the trench, it is important to strictly follow the tightness rules of the building. If you can’t close it with just boards, then the formwork can be sheathed from the inside with the help of roofing material. The finished structure should be distinguished by its strength and rigidity, which will help it withstand the concrete pressure normally. To do this, the walls of the structure are fastened between each other with special jumpers every few meters. To create a formwork for a strip foundation with your own hands is quite simple and will not be difficult.
So that the lumber used to create the formwork can be used again in the future, it is important to create the structure so that when disassembling, not a single board is deformed.
Concrete brand selection
Before you lay the slabs of the strip foundation, it is important to decide which brand of concrete is best suited and can withstand heavy loads. The choice of concrete will depend on the following factors:
- weight of the finished building;
- the presence or absence of additional load on the base;
- type of soil;
- climatic conditions in the place of residence.
The choice will also depend on the reinforcement used in the construction.
In creating a concrete cushion under the base, you can use concrete of the strip foundation of the M100 brand. Under constructions of a lighter type, for example, a bathhouse, outbuildings, sheds, it is best to use the M200. The construction of a wooden house or the construction of lightweight blocks requires the use of concrete of the M250 brand. For larger buildings, high-quality concrete with special characteristics is used - the M350 brand, its strength reaches 327 kilograms per centimeter square.
Higher concrete grades are used to create buildings that are complex in terms of geometry, as well as in areas with fairly severe climatic conditions. If you take into account all the described characteristics, then everyone will be able to easily choose for themselves the right brand of concrete for the implementation of the strip foundation.
Pouring foundation and laying reinforcement
After the owner has chosen a brand of concrete, he needs to prepare everything necessary for pouring. How to make a strip foundation? Some, in order to facilitate their work, pre-order ready-made concrete in special firms. The rest of the builders prefer to make a solution on their own. To do this, it is best to use a concrete mixer. It carries out the mixing of all components. Their ratio will directly depend on the brand of concrete used, as well as on the design of the strip foundation.
At the bottom of the perimeter of the structure, steel material from reinforcing bars is laid. The larger the number of such rods and the greater their thickness, the stronger the foundation.
The created concrete is poured into the trench and formwork to the level mark and is carefully leveled so that its surface becomes more even and horizontal.
More experienced builders recommend using specialized vibrators when pouring a large foundation, which deepen into the thickness of the concrete itself. They help eliminate air bubbles, making the foundation more uniform in consistency and strong.
After the foundation has completely hardened and is ready, it is important to waterproof its walls with specialized coating materials. A properly created foundation will help ensure safe and long-term operation of the building.
How long can it be used?
The service life of the strip foundation will directly depend on the material used during operation. For example:
- monolithic concrete and rubble strips on cement mortar continue to remain intact for 150 years;
- brick tapes - from 30 to 50 years;
- prefabricated concrete - 50-75 years.
If we consider the design of the finished foundation, then it can be divided into:
- Monolithic - used at the construction site itself.
- Prefabricated - when creating, reinforced concrete typical blocks are used, created at the factory and mounted at the construction site by means of a crane. The prefabricated foundation is created from reinforced concrete slabs - concrete blocks and pillows.
Distinctive features of each type
Depending on the load, builders divide the strip foundation into deep and shallow. The shallow and deepened monolithic foundation is a strong reinforced concrete frame extending over the entire area of the future construction, which helps to provide the houses with good stability when building on low-grade and heaving soils. In this case, you should focus on the principle of "price-strength". The cost of such a foundation will be low - only 15-18 percent of the entire building.
A recessed type of strip foundation is used in the construction of houses with heavy walls or coatings, as well as with heaving soil. It is also important to use a deep foundation when the owner of the house plans to finish the garage or basement in the future. The depth of the foundation will be up to 20-30 centimeters below the depth of freezing of the soil. Such a base needs to use more material. Under the walls located in the building, you can draw a foundation of lesser depth - 40-60 centimeters.
A deep foundation, when compared with a shallow one, is distinguished by its strength and special stability due to the fact that its lower part is located below the level of freezing of groundwater and is not subjected to a deforming process. But it is important to remember that when it is created, the amount of consumables and the complexity increases significantly.
The described types of foundation are usually laid in the summer. When creating them, it is not necessary to use expensive devices, the builder will have enough concrete mixers and a little mechanization.
On sandy or dry soils, a strip foundation is allowed to be laid above the level of soil freezing, but not less than 50-60 centimeters from the soil level.
On deep-frozen ground, a strip-type foundation is rarely used because of its poor resistance to low temperatures.
Pros and cons of precast foundations
Prefabricated strip foundations are often used not only in industry, but also in the creation of private houses and cottages.
The main advantages of such a foundation for a house include fast construction and the ability to load the finished structure after mounting after a certain amount of time. It is important to remember that the cost of this type of foundation will be much higher. During its construction, you will have to use the help of professional builders and lifting equipment.
The main disadvantages include the following factors: strength characteristics of the composite material (with the same thickness) is 20-30 percent lower than that of a monolithic one. The foundation created using prefabricated blocks is not as rigid as monolithic, since it includes many individual parts. The prefabricated foundation cannot be strengthened by means of additional reinforcement, since the blocks will be located according to the standard design. It is possible to strengthen the prefabricated foundation only by means of nets laid between rows of sides, but this will not provide the desired effect.
It is possible to reduce the cost of materials for a foundation of this type by laying the foundation wall blocks and pillows not with a continuous row, but with a certain distance - an intermittent foundation. A base of this type will save about 25 percent of the blocks, which will reduce the cost of the entire building.
Any builder should remember that if there is peaty, silty soil with weak bearing capacity on its site, then it is forbidden to use an intermittent foundation as the foundation of the building.
The strip foundation, consisting of prefabricated materials, loses in its strength and operational characteristics to a monolithic one.
What errors can occur?
The errors described below can adversely affect the quality of construction of absolutely any foundation, including strip:
- During the survey, the characteristics of the soil, its subsidence and heaving, were not considered. The level of groundwater and the depth of freezing of the land are inaccurate. Due to the mistakes made in the project, mistakes are made from the very beginning that adversely affect the state of the finished building - the foundation begins to crack, and sags greatly over time.
- During the work, low-quality building materials were used.
When considering poor quality work, special attention should be paid to:
- wrong axis - the angle of the building is less than or greater than 90 degrees;
- skewed foundation;
- the foundation pit was not dug to the desired level;
- the thickness of the pillow in the trench was not taken into account;
- when the concrete solidified in cold weather, the builders did not maintain the optimum temperature - the concrete did not warm up, which led to a decrease in its strength and strength.
Communications device
Some people who want to independently build the foundation for a future home often encounter when working with utilities. Underground utilities - linear installations with technological devices that are needed for transporting gas and liquid, as well as energy transfer. They include piping for supplying hot and cold water, gas, telephone lines and electrical wires.
In order to understand what kind of communications are of this type, it is important to contact the state institution at the place of residence and get a topographic survey of your site, on which all the main underground communications will be indicated.
In the event that the building to be rebuilt falls into such communications, the builder will have to transfer or use the other technology to bind the house to the site. It is important to remember that the construction of a private facility nearby or above underground utilities leads to the appearance of an additional load on the structure, which can provoke a man-made accident and lead to tragic consequences.
Most often, communications of this kind pass through the site when it is in the village or on the outskirts of the city. If the construction project was created by a specialist in this matter, then all possible methods of solving the problem will be discussed in advance.