Raw brick (another name for this building material is adobe) is an excellent building material. It has long been known to mankind, simple and easy to manufacture and use. More common adobe in southern places, but is sometimes found in the middle lane.
History tour
The first buildings, where raw brick was used, appeared almost six thousand years ago. This is not surprising, since a person needs to live somewhere, and funds for the construction of housing are often insufficient. And it has always been like this: now, a hundred years ago, a thousand ... If we are talking about living near the mountains or in a forest area, then there are a lot of cheap building materials. But what about those who live in the steppes or deserts? There stone and wood were very expensive and not everyone was available. Of course, houses were built from expensive building materials there too, but not everyone could afford such a luxury. And around the fourth millennium BC, a way was found to erect clay buildings mixed with straw.
Properties of adobe, pros and cons
Raw brick with chopped straw is a very convenient building material. Its advantages include extremely low cost. After all, the cost of its production is practically zero, since the feedstock is literally under your feet. Another advantage of the use of this building material is its sound and heat insulation characteristics. Also, adobe is hygroscopic, due to which it has a beneficial effect on the indoor microclimate, absorbing excess moisture and preventing the occurrence of dampness and mold inside. Raw brick, like any building material based on clay, is fireproof and provides significant fire safety of the building.
But this building material has several drawbacks. Walls from raw brick are afraid of moisture, so a good layer of high-quality plaster is required to protect them. In a temperate climate, the brick dries for a long time and slowly gains strength. Also, adobe is unsuitable for construction in the winter. Even in the walls of raw brick, rodents and other pests often like to settle. This can be prevented in advance by using special additives or by properly treating the surface. In addition, the construction of this brick takes a little longer, because the walls need more time to achieve the required strength.
Raw brick and its types
Saman is of two types: light and heavy. For the construction of light adobe brick as such is not needed at all. A mixture of clay and filler is prepared, and the filler is taken proportionally more than clay, and is superimposed on the wooden frame of the structure with the crate. Sometimes adobe is simply laid between the inner and outer wall cladding. The advantages of this method are simplicity and speed. Disadvantages - a lot of wood is required. Heavy adobe - this is the same raw brick with straw. Houses from it are obtained much stronger, more reliable, are built from ready-made blocks. Wall decoration is possible immediately after construction.
Material selection
The firing of raw brick is not done, therefore, in order for it to turn out to be of high quality, and the structure to be strong and reliable, it is necessary at the initial stage to pay full attention to the choice of material, that is, clay. Brick made of unplastic clay will turn out to be brittle, and from very greasy clay it will crack from changes in temperature and humidity. There are many ways to determine its quality. Consider a few of them.
The first method - we mix the clay to the required viscosity, make three small cubes from it with sides of 20 cm each. The first cube should only be made of clay. In the second you need to add about 10% of the sand. And in the last cube you need to add oily clay, also in a proportion of 10-15%. On all the cubes, on one side with a stick or a nail, crosswise diagonally make shallow lines. Their width is approximately 5 mm, and their length is 10 cm. The cubes are dried for a week and a half, and then the lines are measured. That clay, where the lines of steel are shorter by 6-10 mm (compressibility 6-10%), is optimal for the manufacture of adobe bricks.
The second method - clay is well kneaded, a ball is formed from it with a diameter of about five cm and smoothly squeezed with two even planks. Clay of low ductility begins to crack when the ball is compressed to the fifth or fourth part of its diameter. Medium ductility - cracks appear when compressed by a third of the diameter of the ball. High ductility - crack when compressed to half the diameter. Optimum ductility is average. Bring to the required plasticity with sand or oily clay.
The third method - a roller about 20 cm long and 1-1.5 cm thick is formed from well-mixed clay. The roller is wound on a tube with a diameter of 20 cm. Maloplastic clay is very cracked and torn, highly plastic clay remains completely without cracks, and the most suitable clay composition forms mesh of small cracks.
Clay preparation
The best option would be to prepare the clay ahead of time. Fold it in stepped ridges with a width below to two and a half meters and a height of up to a meter. Pour each step layer with water and stand the material for one winter. But you can use clay without preparation. You need to mix such a quantity of clay so that there is enough work for one day. For calculation: to make 1000 pieces of standard raw brick, you need almost 3 cubic meters of clay. It is scattered in layers of 15-20 cm, crushed and mixed with oily clay or sand and with the filler that is selected, that is, with chopped straw, chaff, chopping, etc. Do this gradually and only in a dry state. On the edges of the working platform clay walls are made to hold water. Then they begin to fill the mixture with water. Usually there is water about 20-25% of the amount of clay. The clay is mixed to a homogeneous mixture with shovels, legs, concrete mixers.
Brick making
As a rule, the sizes of adobe blocks are of three types and depend on the climate of the area where the house is being built. The drier and hotter the climate, the larger the blocks are made, as they can dry well and gain the necessary strength. Small blocks have dimensions of 30x14x10 cm. Medium - 30x17x13 cm. Large - 40x19x13 cm. Do not forget that during drying the bricks lose up to 10-15% of the volume. Therefore, the form is made 5-6 cm larger than the future brick. Forms can be made on one, two or four bricks. You can do it without a bottom, or you can do it with a bottom in the form of boxes with handles. For better separation of the finished product from the mold, it is possible to drape its walls from within with dense polyethylene.
Brick blocks are made in the same place where they will subsequently be dried. If necessary, the clay mixture is transported on a trolley, superimposed with a shovel into top forms, rammed with a board, excesses are carefully cut, and the blocks are laid out to dry.
Drying of finished products
The finished adobe brick is pierced in 2-3 places with a thin (1.5-2 mm) wire and held for three days on the molding platform. Periodically, it is turned over for uniform drying. After this period, the blocks are placed on the rib and dried for another 3-5 days. And only then the bricks are stacked in piles with a small gap between them. From above, the blocks are covered with mats, shields, tarpaulins, polyethylene, etc. The main thing is to prevent moisture from entering during drying. The drying process proceeds depending on weather conditions from 2 weeks to a month. The degree of readiness can be determined by looking at the kink. The entire surface of the fracture should be monophonic, without spots in the middle. Also, a brick thrown from a height of two meters should remain intact and put in water for 48 hours should not lose its shape.
We build a house from adobe
As already mentioned several times, during the construction of raw brick, special attention should be paid to the insulation of the walls from moisture.
The foundation for blocks of adobe is preferable to the tape type, centimeters 20-25 wider than the masonry itself. This is done to protect the walls from rain spray. The height of the foundation is 50 cm and above. Material - rubble stone or concrete. A waterproofing layer is required on top of the foundation.
Walls are usually built: external - from 50 cm thick, internal - 30-40 cm. The solution is made of water, one part of clay and one part of sand. Also, the masonry can be reinforced with reeds, brushwood or straw. Do not lay in the rain. You need to immediately cover the walls and wait for the dry weather. You can not build walls in the winter. Immediately after the construction of the walls, they need finishing with plaster. It is better to take gypsum plaster, since cement has an insufficiently good adhesion to raw brick.
The roof is made light to reduce pressure on the walls, and with a large overhang up to 70-80 cm, to push the drain away from the walls. The floor can be insulated with expanded clay, and on top make a boardwalk on the logs.
Conclusion
That's all the main points that relate to the production of raw bricks and what you should pay attention to when building a house from it. Deeply erroneous is the opinion that such a construction is short-lived. A house made of adobe, built in compliance with all technologies, will stand idle for hundreds of years. Such houses are warm in winter and cool in summer. Not without reason interest in houses from adobe blocks returns all over the world.