We make a caisson for a well with our own hands - types, preparation and installation

click fraud protection

When laying an autonomous water supply for your home you need to take into account a lot of subtleties. For example, at what depth the soil freezes in winter. After all, it may happen that the pump with water and auxiliary equipment will freeze, and the house will remain dehydrated. To prevent this, the caisson, an auxiliary chamber located underground, around the well, below the freezing level of the soil, will help.

It always maintains a temperature above zero, and the pipes and equipment are protected from damage by frost and groundwater. Also in the caisson are equipment - expansion tank, pump control unit, filters, - for comfortable access and maintenance.

Stages of work:

  • Preparatory and excavation works.
  • Concrete caisson.
  • Metal caisson.
  • Installation of plastic and metal caisson.

There are several options for the caisson design.

caisson_equipment

The caisson made of solid concrete is a reliable and durable construction, however its construction is not easy and may require the use of equipment. Concrete has a high thermal conductivity, so the construction will need to be insulated.

The caisson made of brick is also reliable, and it will be necessary to insulate it, but the material cost is higher. Like the concrete, it exerts pressure on the ground, which in time can lead to deformation of the pipes.
A caisson made of concrete rings can only be built using machinery, since the rings themselves are heavy, and they need to be installed as precisely as possible. Also, the high price of the elements does not contribute to the popularity of this design.

The metal chamber caisson can be welded independently or purchased ready. Cons - it needs to be well insulated and waterproofed, as the metal is prone to corrosion. Of the advantages - the possibility of assembling the structure on the surface and then lowering the poses of the ground. With the experience of welding and inexpensive metal, this caisson is inexpensive.

caisson types

Plastic caisson is a modern solution. The finished structures are airtight, non-corrosive, weigh little and have low thermal conductivity, with proper installation additional insulation is not needed, and the temperature does not drop below +5 degrees. Armored versions are more expensive, but they do not require concrete pouring on the contour, like thin-walled ones. Plastic caisson is cheaper than finished metal.

The dimensions of the caisson are chosen depending on what equipment is supposed to be installed in it, taking into account that the person there should be free to be placed to service the equipment, standardly, it is 1m * 1m or 1.5m * 1.5m. The structure itself should be leakproof, if the ground water lies deeper than 3 m from the surface, and there is no flooding. On sites with a high groundwater level, a plastic caisson is the best choice.




The shape of the caisson - square or round - depends on the material used. Caisson on the site is quite possible to install independently, although the technique and assistance will greatly simplify the work.

kessoni2

Excavation and preparation of

Before excavating a caisson around the well, a foundation pit is excavated. Its dimensions are determined by the parameters of the future caisson. Between its walls and the caisson should remain 20-30 cm of space. If a metal or plastic caisson is installed, the pit is dug out so deep that after filling the cushion and installing the caisson, its upper part protrudes 15 cm above the ground. So, water will not get into it when melting snow or during rain. If a concrete caisson is being built, the depth is made more so that the lid of monolithic concrete with a layer of soil on it is level with the surface of the earth.

The pit should be located so that the hole of the casing is not in the center, but slightly offset to the edge. So the equipment in the caisson is more convenient. The casing itself is welded with a sleeve 10-15 cm long, with a diameter slightly larger than the pipe itself.

The excavated excavation is covered with a layer of waterproofing, which can be used as a roofing material, geotextile or a foundation film. At its bottom is covered with a layer of rubble 15 cm thick. It will serve as a floor in the case of a concrete caisson, since the moisture inside the structure can return to the ground through rubble.

montaj_kessona_b

From the caisson to the house, trenches are dug at a depth below the freezing level of the soil - 50-200 cm. They will lay pipes for water and supply the pump with electricity. If it is planned to build a concrete caisson, then it is better not to connect trenches to a trench, then its walls on one side will serve as a formwork.

Caisson made of solid concrete

Before erecting a concrete caisson, it is necessary to make sure that the ground water lies deeper than 3 meters, because at their high occurrence even the concrete floor will not save the construction from frequent flooding and the appearance of dampness and mold. For a concrete caisson with a size of 1.5 * 1.5 m, the pit should be approximately 18 * 1.8 m.

. At 7-8 cm from the wall, the reinforcing mesh should be knit in 30 cm steps. It should reach the very top of the structure, but if concretewill be flooded in several stages, then the reinforcement can also be built up gradually. For the reinforcement, a rod with a diameter of 8 mm is used.

In 6-8 cm from the grid, formwork is assembled according to all the rules from planks or sheets of OSB.When using boards it is better to lay the film from the inside, fixing it with a stapler, so the concrete will not leak through the possible slots, and it will be easier to remove the formwork in the future. Like the armature, formwork can be installed only at the height to which concrete is to be poured on a given day.

beton_kesson

When pouring concrete, each layer is vibrated manually or with a vibrating platform. In the lower sections of the formwork, it is convenient to feed the concrete through a tray of sufficient length from tin or bonded OSB sheets. After 4-7 days from the moment of pouring concrete, depending on humidity and ambient temperature, the formwork can be removed. Completely concrete will solidify in a month, only then it is possible to install equipment in the caisson.

Also after full hardening inside its walls in the place of supply pipes holes are made using a perforator. Pipes must enter the caisson through special metal or plastic gaskets or be welded at the connection point. During laying and construction work, the ends of the pipe should be better protected with a metal sleeve of a slightly larger diameter.

On top, the concrete caisson is closed with a lid of the same material. For its pouring from the boards, fastened by the bars to the screws, a shield is assembled. It should be able to withstand a considerable weight of concrete, therefore for a caisson cover with an area of ​​1.5 * 1.5 m, at least 6 bars are needed. On the prepared shield, lay the armature, connected with a step of 15 * 15 cm. In the places where the ventilation pipe will pass and the hatch will be located, it is necessary to provide holes and install pieces of pipe or other fences of the required diameter.

The finished formwork is poured with concrete, which will also dry for 3-4 weeks. To prevent the formation of cracks on it, you should periodically wet the surface with water. After the final drying, the top of the caisson is filled with a chamois, which serves as a good heat insulator. The hatch can be both metal and solid wood.

For better heat and waterproofing the walls of the caisson from the inside are treated with bituminous mastic( how to do it, read here) or other composition with a similar action and insulated with expanded polystyrene foam.

Metal caisson

For a sealed caisson, plastic or metal structures are used, the latter being self-made using a welding machine. For this purpose, steel thickness of 4 mm or more or pipes of similar thickness of 1 m in diameter( used in industry) are suitable. In case of construction of a caisson from sheet steel, choose a rectangular or square base with a side of 1 or 1.5 meters, with a height of 1.8-1.9 meters in height. Carefully monitor the quality of welds during welding. In the walls of the metal caisson there are holes for the introduction of pipes( at the bottom - casing, on the side - for water and for the cable), and in the upper part - for the hatch.

When installing a metal caisson, the casing is cut to the ground level and then welded to the hole in the lower part of the caisson. As in the case of a concrete structure, it is better if it is not located in the center, but closer to the wall of the structure. The upper hatch and the part projecting above the ground must be insulated, for example by spraying foamed polystyrene.

Metal is prone to corrosion, especially at welding points, so the caisson is primed from the inside and treated with anticorrosive agents, and externally with bituminous mastic.

kesson4

Installation of metal and plastic caisson

Sealed caissons are installed in the same way. The structure is placed on the bars above the pit, and then, removing them, carefully lowered so that the hole coincides with the casing. With this work without an assistant can not cope. The installed caisson is leveled. In the holes hold pipes and weld them, connect electricity, install and connect equipment.

In the case of a plastic caisson, openings with pipes are not welded, but are connected by means of sealed heads. If there is a need to strengthen the thin walls of the plastic caisson, concrete is poured into the space between the walls of the pit.

instagram viewer