When can I build a shallow strip foundation?
Folk love this kind of sole received, thanks to an ideal set of useful characteristics:
- Simplicity of the device. The depth of the shallow basement is only 50-70 cm, which allows to finish the work of the zero cycle in a very short time and without much trouble.
- Save money. This is the cheapest base for a heavy building, since for the construction of underground tapes a minimum amount of consumables is required.
- Reliable bearing. Despite its compactness, the sole completely copes with the task assigned to it, that is, the built house is tightly connected to the ground.
But, it must be remembered that not every site is suitable for the construction of a shallow basement foundation. If neighboring neighbor has favorable conditions for its construction, this does not mean that nature has endowed your scrap of earth with such a "winning ticket".For the final diagnosis, geological prospecting is carried out, and if it is determined that on the site:
- a uniform sandy( rocky) soil type;
- the groundwater table is below the soil freezing level by at least 40-50 cm;
then you just got lucky. You can safely build a shallow ribbon foundation yourself and not worry about the future of the building.
How best to build a shallow strip foundation?
The strongest and most reliable foundation is a monolith, which, thanks to the lack of seams in the structure, has the longest warranty period of "life"( from 150 years).But, self-delusion always has problems in designing this type of foundation, because it's right to determine the proper iron "stuffing" for concrete, oh, how not easy. The thickness of the reinforcement is proportional to the future loads in the system, and you can learn them only by performing a series of complex mathematical calculations. But, even correctly picking the diameter of the metal rods, you can make mistakes when they are mated. An incorrect "cage" in the reinforcing grid threatens the appearance of a tense section in the foundation. Sooner or later this flaw will break the integrity of the concrete, and a crack will appear at the base, which will hurt the "health" of the ground part of the building very painfully.
You will greatly simplify your task by choosing for the device a shallow deep foundation foundation method of butane-concrete masonry. And if near the construction site you get a boot( river stone), then the main building material actually lies under your feet. The main thing is to correctly choose it:
- Quarry stone is a flat cobblestone with approximate dimensions of 20 cm by 30 cm( width / length).All elements of the masonry should be approximately( but not strictly!) The same.
- For construction use only whole samples without visible cracks. Also, stones should be thoroughly cleaned of dust, sand and dirt.
- You can check the quality of the boot by the sound: hit it with a hammer and if you hear a clear, sonorous sound, then you have the right material in front of you. Its strength index is 1000 kg / cm2.
- Stone stonework has no stitching. The main thing is to ensure the free "floating" of the buta in the concrete.
The width of the shallow basement is chosen as follows: on each side of the future wall of the house there should be a ledge of at least 6-8 cm. Then the desired size of the buta is determined by the ratio:
Maximum width of the stone = 1/3 of the width of the base strips
Concrete mortar for work is kneadedrecipe: cement / sand / gravel in the ratio - 1 /3/ 5. The mixture must be "heavy", so choose cement grade M-400( M-500), crushed stone - not larger than 30 mm and medium-grained sand.
Water is added slightly more than with a standard casting of a monolith with a reinforcing cage( where the proportion of cement / water is 1 to 0.68).The mixture should be more liquid, so that the stones could safely dive into it with a "head".
How to build a shallow band foundation of buta?
Works of the zero cycle begin traditionally: the site is cleared and deprived of vegetation cover( 5-8 cm).Then make a marking of the base and dig trenches( with a margin for the parameters of the bands of 20 cm).After laying the drainage cushion( 15 cm sand + 5 cm crushed stone), waterproofing and installation formwork, proceed directly to the pouring of the base.
For those who want to build a self-supporting concrete strip foundation with their own hands, we offer a description of the correct technique for performing shallow masonry:
- A 15-centimeter clean concrete layer is poured into the bottom of the trench. It will cement the bottom of the masonry and prevent the cobblestones from pressing into it a "hole".
- After the first setting of the starting layer, another solution is poured into the trench( at the level of 20 cm) and carefully pressed to remove air bubbles. Then immediately begin to lay stones, half immersing them in concrete. The distance between adjacent masonry elements should be 4-5 cm.
- A portion of concrete 20 cm high is poured again and the entire process is repeated.
Such a device of a shallow foundation with its own hands is especially advantageous for buildings with a minimum height of the plinth( 15 cm).The strength of the sole is impressive: it can be safely set up a two-story brick house with a mansard. Just remember that butobeton is "afraid" of the cold. Careful warming of the blind area and the side surfaces of the base - always!
Some "craftsmen" change the technology of concrete cladding, first installing stones, and then pouring them with concrete. With such a sequence of works, the probability of the appearance of air "pockets" in the base is great, since the bottle will prevent the working solution from qualitatively "repelling".
