With the increase in the number of private cars, amateur harboring is gaining momentum, and most motorists are trying to build a cheap and at the same time very robust box for transport storage. Considering the desire to keep the machine and the structure from possible problems with soil subsidence, and taking into account the complete lack of information about the nature of the soil on the site, in most cases a decision is made-the best foundation will be a monolithic slab for the garage.
Preparation of an excavation for pouring a slab under the garage
Technologically, the preparation and manufacturing of a concrete slab base for the construction of a garage is no different from the arrangement of a shallow foundation, the difference is only in the scope of work:
- The exact position of the future plate is marked on the site, planning works are performed, soil and soil are removed to a depth of 40-50 cm;
- The pillow of several layers of sand-gravel mixture is laid and tumbled, the film, insulation and waterproofing are laid;
- Installed formwork, laid two layers of bar reinforcement, the bottom layer at a distance of 3-4 cm from the waterproofing, the top - 3 5 cm from the final top surface of the plate.
Thus, it is possible to effectively use the excess stiffness of the plate to strengthen the garage box. Stacking the fittings in the garage walls will make the whole structure much stronger and stiffer. If the ceiling is planned in the form of a plate casting, the reinforcement will only strengthen the walls of the garage and, possibly, in the manufacture of the reinforcing belt there will be no need.
First lay out and bandage the bottom layer of the reinforcement. After laying the "frogs" or standard cups attach the reinforcement of the second layer. It is necessary to knit the rods, and not to weld them. Most experts recommend knitting with a soft wire, motivating the recommendations so that the protective layer on the armature is not violated. In reality, knitting with wire allows to get a strong and simultaneously movable reinforcement skeleton. In the process of pouring the formwork, the fittings will not move, and when the foundation of the garage is hardened, the ligation of the bars will allow to level and compensate the stresses in the concrete.
How to fill the stove under the garage with your own hands
Standard strength calculation using software packages gives the optimal value of the thickness of a solid board for the foundation of a one-story garage of 120 mm. For the bottom of the garage box with a size of 6x4 m it will be about three cubic meters of concrete solution.
In reality, the thickness of the slab base is selected somewhat higher than the calculated value:
- At first, there is a desire to raise the floor of the garage above the ground level, at least 10 cm. Most often in private garage use a swinging garage door. Therefore, a gap is required to ensure a normal opening of the gate even in winter, with plenty of ice and snow in front of the entrance;
- Secondly, melt and rain water should not get inside the garage, even with oblique showers;
- Thirdly, a high stove guarantees a normal use of the garage even in unforeseen situations, for example, subsidence of a part of the foundation or punching of the ground before entering the room.
It is advisable to fill concrete with a slab base under the garage foundation in one step, if the volume of concrete solution in the mixer is not enough, the pouring must be performed with a difference in time not more than 3 hours.
After pouring it is necessary to level the surface of the concrete solution with the ironing device. Thus, a very smooth and solid foundation is obtained.
Methods for optimizing the form of the basement under the garage
The thickness of the slab in 120 mm is sufficient for strength, but not enough to build a high foundation. Filling a foundation of half a meter thick in order to raise the floor level is expensive and pointless. For a slab of 0.5 m, at least 12 cubes of concrete or 26-30 thousand rubles of additional costs will be required. Therefore, often resort to an unusual foundation of the foundation - sectoral.
The construction of such a plate can be compared with several parallel ribbons of a shallow foundation, on top of which a full-fledged thin monolithic slab is cast. The layout of the reinforcement is no different from the standard version.
The technology of assembling such a foundation is carried out in the following sequence. On the perimeter of the garage and inside the contour a trench, 50 cm deep, is pulled out. Within the contour one is made, more rarely two longitudinal and one transverse strips of a shallow foundation. There is a gravel-sand cushion, waterproofing, EPS. The space between the tapes is carefully compacted and sanded off, followed by the laying of waterproofing and insulation. The ribbons are reinforced in the bottom and upper part of the straps of two bars. Monolithic slab has its own reinforcing frame in one layer.
After the formwork has been installed, the total slab of the slab and MZLF will rise above the ground to a height of about 20 cm. At the same time, the monolithic slab itself is thin and at the same time high, raised above the ground due to the layered EPS. The result is a thin monolithic garage foundation, reinforced with stiffening ribs.
Pour any variant of the foundation plate only in one sitting with one volume of the mixer. The estimated version of the concrete solution will require about 5 cubes, which corresponds to the standard charge of a concrete mixer based on KAMAZ.
Features of the monolithic basement under the garage
The main and main positive feature of the slab is that, in the case of the proper formation of a foundation pie, even on weak and wet soils, the monolith cement and strengthen the entire garage box, even if it is made up of aerated concrete blocks. In addition, the garage is not a residential building, but more often, just a storage place for a vehicle, tools, spare parts and unnecessary trash.
What is the stove under the garage is different from the basement of the apartment house
The stove under the garage works under more severe conditions than the foundation of a residential building, it is rarely heated. Due to specific use, a number of additional requirements arise:
- Often, the garage space is not heated, accordingly, a solid plate is fundamentally heated by internal heat. Therefore, if a box of a building does not cost a wall to the wall in a close row of garage cooperative buildings, the slab foundation must be thoroughly insulated;
- A monolithic slab is often called a floating slab, but this does not mean that the slab foundation is capable of standing unproblematically in any conditions. It works perfectly under conditions of a heavy brick boxed house, but it can fall under the weight of a light garage due to the powerful punching of soil and high groundwater;
- Strangely enough it sounds, but with the arrangement of the slab you can not just fill the formwork with reinforcement with concrete mortar and get the best foundation in the world. The load on the part of the foundation plate under the front wall of the garage with the gates and on the other sections is different, primarily because of unequal operating conditions.
Why it is necessary to strengthen the front edge of the plate under the garage
If the garage foundation plate is made in the standard version, without reinforcing belts and stiffeners, the load from the car can cause a small, sometimes even a fraction of a millimeter, deflection of the base. The strength of a properly reinforced slab 100-120 mm thick will be enough to withstand the deformation without breaking.
The main danger is not this. If the cushion under the basement is not properly constructed using dirty clay sand, or the tampering technique is broken, then periodic tilts of the front edge of the base cause increased compaction of the soil and cushions, and over time a small cavity is formed under the plate. Over time, during the rainy season, the cavity will be filled with water, and after the onset of frost, due to the formed ice, it will begin to lift the base plate.
If you do not take measures, a thin and flexible plate will continue to "break" the walls of the garage until the appearance of full-fledged cracks. In this case, the armature released from the slab base when pouring the foundation of the garage is very useful.
The main condition of plate conservation is effective drainage and proper blind area
Rarely, when so lucky that on a site for building a garage under a layer of soil is a rock, and the slab can be cast simply into the excavated pit after laying the waterproofing. Often found opposite - you have to remove a large amount of clay, pour gravel, lay geotextile, a layer of sand, and only after that pour the concrete. In this case, before laying the sand cushion, it is necessary to make a branched drainage system from perforated pipes.
At a minimum, two pipes must be laid under the front part of the plate foundation and under the concrete area at the entrance to the garage. In this case, it is usually possible to effectively remove groundwater and surface water and completely avoid the risk of swelling.
An effective drainage system avoids 99% of the problems associated with deformations and destruction of the soil soils capable of breaking reinforced foundation plates up to 25 cm thick. The water collected in the tank can be very useful for household needs, for example, for washing the car.
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