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Cellars and undergrounds are best suited for storing crops. But the underground can not be made in every house, but you can make a cellar even in a site with a high level of groundwater. It is important to know where and how.
Choosing a place for the cellar
The optimal place for a cellar is on a natural or man-made hill. If there are no drops on the site, you need to find the “driest” site with a low groundwater location. You can determine by the vegetation – where it is the smallest, there is water far away.
Ideally, if you have a geological study of the site (ordered when planning a house). There, with sufficient accuracy, the occurrence of aquifers is indicated. If there is no such study, the approximate level of groundwater can be determined by the depth at which the water mirror is located in the wells.
Another option is to drill a well at a depth of about 2,5 meters in the proposed location. If there is no water in it, you can make a cellar, buried 2 meters or a little more. It is necessary to drill either in the spring, after the snow melts, or in the autumn after heavy rains. At this time, the highest level of groundwater and surprises in the form of flooding, then you will not have to be afraid.
Based on the results of the research, they are determined with the type of cellar:
- If the groundwater level is below 1,5 meters from the surface, a deep cellar can be made.
- If the water is at the level of 80 cm, you can make it semi-submerged.
- The ground cellar is rather a vegetable store. It requires a lot of work and is rarely done in the private sector.
There is another type of cellar – an underground, which is arranged under the house, if the house has a sufficiently high base (1,5 meters and above). Then they dig a small pit about 2 * 2 meters in size, deepening no more than a meter. At the bottom, with entry to the walls of the pit, waterproofing is laid, gravel (10-15 cm) is poured, and a plank floor is laid. If the water is already close, it is better to pour a concrete slab using standard technology.
The walls are laid out with bricks or a log house is made of impregnated timber, they are well insulated from the outside. The cover of the cellar under the house is made below the floor level, also insulated. A slightly larger cover is arranged in the floor. This completed the construction of the subfloor. This type of cellar makes sense only in a house of permanent residence – it will always have a positive temperature. In houses of seasonal residence without heating in winter, it will freeze, so it makes no sense to cost such a cellar in the country.
Materials
The choice of material for the cellar also depends on the level of groundwater. In a dry place, you can build with whatever you want – any material suitable for this purpose: impregnated wood, brick, concrete, building blocks.
If the water is close to the surface, it is necessary that the material is not afraid of moisture, has a low hygroscopicity (preferably close to zero) or has the ability to significantly reduce it. But these requirements are met, in general, only concrete and metal. Concrete is preferable – it is definitely not afraid of getting wet, it does not absorb water very much, although it can conduct it through capillaries. Concrete is good because there are various ways to make it almost impervious to water in any form:
- Additives are additives that give concrete certain properties. Including there are additives that make it practically non-conductive and non-absorbent.
- Hygroscopicity can be reduced by vibrating concrete during laying (there are special vibrators for concrete). Due to the compaction of the structure, its density becomes much higher, hygroscopicity decreases.
- Deep penetration treatment. For concrete, cement-based compositions are used, which include polymers. Polymers block the capillaries through which water seeps through. Double treatment allows 6-8 cuts to reduce the amount of moisture seeping through the concrete.
- Rubber paint. It is used for swimming pools, but in extreme cases it can help keep moisture out of the cellar.
All these tools in a complex, or one or two to choose from, will help make the cellar dry, even in areas with a high level of groundwater.
You can also build a cellar on high groundwater from metal. A sealed box of the right size is brewed, spacers are welded to the bottom and walls. This metal box is treated from the outside with an anti-corrosion compound (several times) and buried in the ground. If the seams are done well, water will not seep through, but there is another problem – with a lot of water, this box can be pushed to the surface. To prevent this from happening, spacers are welded, but they help only up to a certain pressure created by water. It may well happen that such a cellar “floats up”.
When building a cellar with a high level of groundwater, ceramic bricks are still acceptable. But over time, it crumbles from water, although there is an opportunity to significantly reduce its hygroscopicity – process it several times with the same deep penetration impregnation. And yet, a brick with high water is only an extreme option.
How to make a concrete cellar with mobile formwork
The standard technology for building a concrete cellar has been described many times. It is not very good, because a large amount of material is needed for the formwork, and digging a pit is not happy – it must be much larger than the dimensions of the cellar in order to be able to install this formwork. There is a more rational technology – with a concrete knife and phased pouring of the walls. This tactic is used in the construction of wells, but can be used to build a cellar.
Pour the knife
It all starts with filling the knife. His profile is shown in the picture. In the figure, it is drawn round – under the well, but it is better to make the cellar rectangular. This concrete knife is poured right on the spot. So, we dig a small pit around the perimeter of the future cellar. In cross section, the pit should be triangular, with a bevel directed inside the perimeter (as in the photo above).
We knit a reinforcement frame of the same shape. In this case, fiberglass reinforcement was used – it is cheaper and easier to deliver. Steel will be used for the ceiling and floor.
When making the frame, we leave the reinforcement outlets 15-20 cm long, directed upwards – the next reinforcement belt will be tied to them. The frame is installed in a finished pit, covered with a film. This is necessary so that the walls of the knife are smooth and pass the ground well.
We make concrete in a concrete mixer – the small volumes required for one pour do not allow ordering at the factory. We make concrete grade M 250 (1 part of M 500 cement requires 1,9 parts of sand and 3,1 parts of crushed stone, water – 0,75). To increase the strength, polypropylene fiber is added, and Penetron-Admix (an additive for greater strength) is dissolved in water.
Concrete is made of low flow, as it will be processed by a vibrator. The sides were filled in stages, immediately processing with a submersible vibrator.
Making walls
Next, the concrete was covered with a film, periodically moistened. While he was setting, they were collecting formwork. The edged board 40 * 150 * 6000 mm was passed by a planer, the formwork panels of four boards were knocked down. In height, they turned out to be about 80 cm. When assembling, the boards were fitted tightly so that the mortar would flow out less.
We waited until the concrete gained its design strength (more than a month has passed since the pouring). To make a cellar using this technology, the knife must be durable. The frame of the next row was tied to the reinforcement outlets left earlier. At the same time, we also leave issues of the order of 15-20 cm for the “binding” of the next belt.
To increase the rigidity of the frame, the corners are reinforced with a metal bar bent in the form of the letter “L” (side length 40 cm).
We put formwork panels. So that they do not fall apart when pouring concrete, they are fastened inside and outside with corners. Inside, 4 corners are placed (on self-tapping screws), outside – 2 each. The distance between the two shields is fixed with the help of studs (they are visible in the photo below).
So that the walls of the cellar were smooth and water did not leave the concrete, the inner surface of the formwork was sheathed with polyethylene. The surface of the first standing concrete must be cleaned of dust that has accumulated. We do this with a high pressure washer (available on the farm). Next, we install the formwork, pour concrete, process it with a vibrator.
We cover the poured concrete with polyethylene, periodically water it. Formwork can be removed after two or three days. After a few more days, you can begin to lower the walls. To do this, we take out the soil inside the perimeter. We dig evenly so that the walls sit without distortions.
For the first time, the walls sagged by about 60 cm. This is the height of the wall pour (about 20 cm of the formwork overlaps the previous fill.
Further, according to the “knurled” technology – we tie the reinforcement, reinforce the corners, put the formwork. Only this time, in order to make it more convenient to place the shields, inside, about 15 cm below the edge, pieces of boards are stuffed. They rest on the inner shield.
Then the outer shields are installed. They “hang” on the lower studs threaded through both shields. The top studs fix the required wall width. Shields are tightened in the corners with metal corners.
Next – pouring, vibrating, covering, waiting. After a week and a half, you can continue to deepen. We do this until the walls are of the design height. In this case, it took 4 fills of 60 cm each. The total height turned out to be 2,4 m. They buried it so that the upper cut was slightly below the ground level.
Those bottles that are put on the reinforcement are necessary so that the film covering the concrete does not tear. The idea turned out to be very useful.
Geotextiles were spread on the earthen floor. It will compensate for uneven loads. It also serves as a “rug – then a lot of work on your knees.
Stopper
To prevent the walls from sagging further, the knife must be “stopped”. To do this, we knit a frame from reinforcement, similar to the one that was made for the knife.
To install it, we drill holes in the knife, into which we drive reinforcing bars. We tie the connected frame to them, leaving the outlets of the reinforcement for connection with the reinforcement of the floor.
We put the formwork, fill the “stopper” with concrete.
Concrete cellar floor
After the concrete has set, we disassemble the formwork, it’s time to make the floor. First, the base is made. Sand was poured onto the geotextile (about 10 cm), leveled with a shovel, then with a rake, then with a roller. Two buckets of cement were scattered over the entire surface, mixed with a rake with a top layer of sand, and again compacted with a roller. They spilled water from a watering can with a dissolved Penetron-Admix additive, rammed it with a manual rammer. After tamping, sand is not crushed underfoot.
This operation was repeated two more times. The top layer is flush with the edge of the stopper. Let the preparation under the stove dry. After drying, the crust is very durable.
The base was washed and dried. They laid the finished stack of 6 mm wire in 10 mm increments. The grid was connected with the releases of the reinforcement from the knife. She was put on pieces of boards, which were removed as they were poured.
From two strings stretched from corner to corner, beacons were made for pouring concrete – the total height of the slab is 10 cm.
Overlapping and ventilation
We disassemble one formwork shield, nail the docks, stepping back from the upper edge of the wall 40 mm – this is exactly the thickness of the boards. In one corner we install a meter pipe, fasten it with one clamp, in the opposite we put a three-meter pipe on three clamps.
Three formwork panels fit perfectly on the attached boards. We disassemble the rest, cut it so that there is a hatch for the entrance. The gaps between the boards are sealed with mounting foam, after polymerization, the excess is cut flush with the boards.
Below, from the cellar, spacers are installed. At the top they are fixed with corners, at the bottom, trimmings are laid under the boards so as not to push through the not fully matured concrete.
From above, the boards and the wall are washed with a high pressure washer and dried. Covered with a layer of roofing material, which was attached to the boards with staples from a construction stapler. The entrance to the cellar is 1*1 meter in size, its edges are limited by formwork boards.
Next, formwork is installed around the perimeter. We fasten the boards, tighten them in the corners with long nails. Then we wrap it with roofing felt, install spacers that rest on driven stakes. Powerful struts are needed – the weight will press a lot.
We also make three reinforcing beams – two lower bars 16 mm, two upper 14 mm, they are interconnected by an 8 mm bar. Two beams were tied, ready to be laid in place, connecting them with the releases of reinforcement from the walls. The third was assembled on the spot – its rods pass through the finished beams.
After 12 mm reinforcement, we knit a mesh with a step of 20 cm. We tie the bars to the outlets from the wall. Some difficulties arose when bypassing the ventilation pipes. I had to bend the armature. The bars that ended near the entrance were bent 15-20 cm up. The reinforcing cage for the entrance will then be attached to them.
In order to conduct electricity to the cellar, two holes were drilled, the wires in the corrugated pipe were passed through them. Next, they filled everything with concrete.
A few days later, when he seized, a formwork was installed over the entrance. First, the inner box, then the reinforcement frame, then the outer one. Also filled with concrete.
After the concrete gained design strength (28 days from pouring), the wall half a meter down and the floor slab were sheathed with insulation – EPS (extruded polystyrene foam). He was “planted” on bituminous mastic – along with waterproofing.
The props inside are left for two months. Then almost everything was removed, leaving only a couple, just in case. The first crop appeared in the cellar.
Now you know how to make a concrete cellar with a phased pouring of the walls. It took a lot of time, but the costs turned out to be stretched over time.
How to make a cellar from concrete rings, see here.
Cellar in a country house made of bricks (under the hozblok)
For the construction of a brick cellar, our summer cottage is 100% suitable – groundwater is below 3 meters, the soils are dense, non-porous, so they dug a pit 2,5 meters deep. The dimensions of the cellar are 2,2 * 3,5 m, the pit, respectively, is slightly larger. The entrance to the cellar will be from a viewing hole, and a utility block (metal container) will be installed above the entire “complex”. To save a used brick is taken.
The floor was done as the old people advised: rubble and broken bricks were poured into the bottom in layers, all this was covered with clay and rammed. They leveled the floor, pouring sand, it was also tamped down, after wetting it. Then they began to lay the walls in half a brick. The soil is non-porous, so there is no need to worry about the fact that the walls will be squeezed out.
The gap remaining between the brick and the wall of the pit was filled with clay, which was also well rammed – protection from the top water, which will look for where to leak.
The walls were driven out a little above the ground level, they were covered with a cut board. They laid it tightly – this will be the formwork for the cellar floor slab. From below, the boards were supported with spacers, and a film was laid on top – so that the concrete would not seep into the existing cracks. We put up the sides of the boards, limiting the future slab. The boards in the corners were fastened with corner ties.
Two plastic pipes are inserted into the future ceiling, in opposite corners of the cellar. This is a ventilation system. The slab will be insulated – 5 cm of EPS (extruded polystyrene foam) will be laid.
On top of the insulation made of reinforcement with a diameter of 10 mm, a mesh is connected with a step of 20 cm. The mesh rests on pieces of brick. It is raised above the EPS by 4 cm, the total thickness of the plate is about 10 cm.
Concrete was ordered at the factory – there is an entrance to the dacha. When poured, they bayoneted well.
While the concrete is “ripening”, the walls of the inspection pit and the steps into it are laid out.
After removing the formwork, it will be possible to put a metal hozblok on top.