A correctly calculated and constructed foundation is the key to the long-term and safe operation of any building and structure. There is a certain number of types of foundation, but the most popular of all will undoubtedly be tape. For its manufacture does not require additional equipment. Everyone has the power to build a strip foundation (or strip footings) with their own hands: step-by-step instructions for its construction will help in this matter.
Advantages and disadvantages of the strip foundation
It got its name, as it looks like a reinforced concrete tape buried in the ground. The external and internal walls of the structure with their entire lower plane rest on the surface of this tape. By the type of deepening into the ground, the strip foundation is deepened (from 1.45 to 1.65 m) and with shallow deepening (less than 1.4 m).
The first type is being built for large structures and high-rise buildings, and the second for low-rise construction. By structure, it can be monolithic and prefabricated. Monolithic is poured from concrete mortar, and precast is made of separate reinforced concrete blocks .
For the construction of a monolithic foundation, the following materials can be used:
- Portland cement;
- crushed stone;
- shrapnel rock;
- broken brick;
- steel reinforcement;
The need for these materials can be pre-calculated using a calculator for calculating concrete on a strip foundation or manually.
The strip foundation has several advantages that make it truly popular among all other types of bases:
- low susceptibility to heavy loads;
- simple construction without the use of heavy technical means;
- design reliability;
- the possibility of building on non-uniform in density soils;
- the walls of the structure can simultaneously serve as walls in the basement of the house.
He also has disadvantages:
- construction requires a lot of materials;
- waterproofing is required.
With all its advantages and disadvantages, this type of foundation is widespread, especially in private construction.
Useful advice! In order to calculate the right amount of mortar, calculators for calculating concrete on a strip foundation have long been invented. It is enough to enter the parameters of the trench in them to get complete information about the amount of required materials. Using these services, you can also calculate the cost of the foundation .
Strip foundation yourself: step-by-step instructions
Due to the fact that there is no need to use heavy technical equipment for construction, anyone can build a strip foundation with their own hands: a step-by-step instruction for the implementation of work includes several independent steps.
Preparation for work and marking in place
Before proceeding with the construction of the foundation, it is necessary to plan the terrain and mark the axes. Planning means leveling the entire construction site in height. If the height difference in the area is significant, then this circumstance must be taken into account when digging a trench. In higher places you will have to dig deeper, but in lower places the height of the foundation will be greater.
Axes are marked with a triangle with sides 3: 4: 5. The corners should be straight, and all the diagonals equal.
This is digging trenches to the required depth along the marking axes. Its depth depends on the density of the soil, the distance to the groundwater, the weight of the building being erected. For high-rise buildings, it’s 1.5 m, and for private houses 1 m is enough, if the soil allows.
After digging the trench, at its bottom, tamping and drainage is carried out with a layer of sand and gravel. This is called a pillow. The width of the trench depends on the type of materials the walls will be made of. For private houses, 60 cm is enough.
Formwork yourself for a strip foundation
When the trench is ready, begin to build the formwork. Some construction companies have in their arsenal prefabricated reusable formwork, which is very convenient to use. Formwork yourself for the strip foundation can also be made. To do this, you need lumber: bars and tes. Its quantity must be calculated individually.
The formwork has the form of a wooden box installed over the entire trench. Since a liquid solution will be poured there, tightness must be observed. If this cannot be achieved only with the help of boards, then it is possible to sheathe the formwork inside the roofing material.
The design must be rigid enough to withstand the pressure of the poured concrete. For this, the walls of the formwork are fastened together with jumpers after 2 to 3 meters. As you can see, creating a formwork for a strip foundation with your own hands is not so difficult.
Useful advice! In order for lumber used in the manufacture of formwork to be reusable, it is necessary to design it so that when disassembling it does not damage the boards.
What brand of concrete for the strip foundation is used
Before you start pouring a monolith, you need to ask a question: which brand of concrete for the strip foundation is the most optimal. This parameter depends on several factors:
- weight of the entire structure;
- the presence of additional loads on the base;
- what reinforcement is used;
- soil type;
- climatic conditions of the area.
For the installation of a concrete pillow under the main foundation, the M100 brand will be quite enough. For lightweight constructions: panel houses, bathhouses and business buildings, the M200 is suitable. The construction of a wooden house or a building of light blocks requires the use of the M250 brand.
For massive structures and buildings, high-quality concrete of the M350 brand is being prepared, with a strength of 327 kg / cm². Higher concrete grades are used for the construction of geometrically complex structures and construction sites in regions with harsh climates. Knowing these characteristics, everyone can determine for themselves: what brand of concrete for the strip foundation is needed.
Laying reinforcement and foundation pouring
Having decided on the brand of concrete, it is necessary to prepare everything necessary for pouring. Some order ready-made concrete in specialized firms. Most people prepare a solution on their own. To do this, it is desirable to have a concrete mixer. All components are mixed in it. Their proportion depends on which brand of concrete for the strip foundation was chosen.
A steel structure welded from reinforcing bars is laid at the bottom of the trench along the entire perimeter. The more such rods are used and the thicker they are, the stronger the foundation will be.
The prepared concrete is poured into the trench and formwork to the level mark and leveled so that its surface is strictly horizontal and even.
Useful advice! When pouring foundations of large volume, it is necessary to use special vibrators that are buried in the thickness of concrete. They expel air bubbles, making the monolith more uniform and durable.
After the foundation is completely ready, it is necessary to provide waterproofing of its walls with coating materials. A correctly executed foundation will give a long and reliable operation of any object.