Caisson for a well: what is it, types, purpose, comparative review of structures and installation rules

Nikolay Fedorenko
Checked by a specialist: Nikolay Fedorenko
Author: Alesia Markova
Last update: December 2019

An autonomous water supply system solves the problem of providing water to homes located away from urban infrastructure. An important nuance of arranging such a system is the full protection of the well from all sorts of negative factors. For this purpose, a special device called a caisson is mounted.

A caisson is a camera designed to equip a wellhead below the earth's surface. It is built above the water intake to provide convenient access and the ability to install equipment for water supply at home. There are several varieties of such designs. It is important for the developer who is going to start arranging autonomous water supply to carefully study all types of caissons for the well and choose the best option for himself.

Self-assembly of a caisson for a well is quite affordable subject to certain rules. Let's try to understand the varieties of caissons and the rules for their installation.

What is a caisson and why is it needed?

Caisson is a sealed container. Initially, caissons were used to carry out work under water, later the scope of their application has expanded significantly. In particular, such products began to be used to protect the head of the well.

Most often, the owner assumes the year-round operation of an autonomous water supply. However, it is very difficult to do this in conditions of a sharp annual temperature difference. Summer heat and severe winter frosts significantly complicate the operation of the well.

At low temperatures, the water coming from the depths will certainly freeze and ruin, and in the worst case, it will break the pumping equipment.

Caisson for a well
Caisson protects equipment from adverse external influences

For uninterrupted functioning of the well, the owner must ensure a stable positive temperature for its head. For this purpose the caisson is also used.

It is a sealed container, which is buried in the ground and fixed on the casing. With additional insulation, the device will protect the well from low temperatures. In addition, the sealed container does not let in ground and waste water, which can damage moisture-sensitive appliances.

Caisson for a well
In order for the caisson to fully perform its functions, it must be correctly installed. The figure shows the design installation diagram

In addition, the caisson is an optimal place for the installation of pumping equipment. Here it will be reliably protected not only from the ingress of groundwater, but also from insects and rodents that can ruin appliances.

A closed caisson restricts unauthorized outsiders access to the tip.

In addition, inside the structure, you can place all the equipment necessary for the operation of the well:

  • purification and filtration systems, reverse osmosis;
  • pump unit;
  • pipelines and shutoff valves, including those with pneumatic or electric drive;
  • automation, responsible for controlling the pump and the entire water system.

The caisson is a container with a neck that closes with a hatch. The height of the structure is usually at least two meters, since the casing pipe enters the structure at a depth of 1-2 m.

The geometry of the products also varies. In cross section, they can be round or quadrangular. In the first case, their diameter should not be less than 1 m, otherwise it will be very difficult for a person to fit inside the camera. It is important to choose the sizes of the caisson.

Too small a design will be inconvenient to accommodate equipment and carry out maintenance and repairs. A large camera will cost unreasonably expensive. Outside the caisson is most often insulated.

At the bottom of the tank, a hole is made into which the casing is inserted. In the side walls are technological holes for laying electrical cables and bringing water pipes. In addition, a staircase is installed inside the caisson, a folding option is especially convenient.

Caisson for a well
The form of the caisson can be any, it is important that it is convenient for placing equipment and does not interfere with maintenance work

The newly minted owner of the well is always wondering if it is necessary to equip the caisson, because this is a rather expensive event? Yes, you can do without a caisson. But it’s not so simple.

Firstly, in this case, it is necessary that the well’s output be in a heated room, for example, the basement of a house. This is necessary to protect the equipment from freezing. It should be understood that the noise level from constantly working devices will be high.

Secondly, you have to use downhole adapter. This device is a compact plumbing adapter that is mounted in a casing.

It consists of two parts. The first is installed on the casing below the GPG level, the second is fixed on the intake pipe.After that, the sliding joint is mounted in the “dovetail” with the help of which both parts of the adapter are connected already inside the well.

The device is extremely easy to install and use. In addition, for many well owners it seems very attractive and its cost, which is much lower than that of the caisson. But you must understand that the installation of the adapter significantly complicates the subsequent preventive maintenance and inspection of the well. In addition, all equipment will have to be located inside the building.

Types of caissons and their characteristics

The caissons are very different in shape. Round in plan and rectangular, with extension at the bottom and without.

Meanwhile, they are clearly divided into three main types according to the material of manufacture:

  • Concrete
  • Brick.
  • Metal.
  • Plastic
  • Polymer sand.

Earlier options with the walls of a wooden log house can now be regarded only as a curiosity or useless exotic due to the high cost, complexity of execution and low consumer properties.

Caisson in the pit
If there are any problems with the installation, then you should not save on the size of the pit - the main thing is to provide access and ease of use when equipping the caisson

The material from which the sealed chamber is made largely determines its operational characteristics. We consider in detail the features of devices made of different materials.

Option # 1 - a chamber made of concrete rings or bricks

Until recently, the most common caisson made of concrete rings can be considered the most common. It is quite simple to do, the design is solid and durable.

Such caissons are made in two ways. In the first case, reinforced concrete rings manufactured at the plant are laid on the prepared base. Upon reaching the desired height, a plate with a lid is placed on them.

Installation of reinforced concrete rings is simpler and faster than the same work on the device of a plastic or metal box, under which it is necessary to dig a foundation pit in advance.

Well box installation diagram
Concrete rings are the most common option for a caisson for a well due to the installation speed.

The second method involves self-casting of the structure. A base is installed on which the reinforcement is assembled under the walls, and after pouring them, for the floor slab with a hatch.

In both cases, the finished structure has all the advantages of concrete caissons:

  • Indisputable durability and strength. Concrete is a very strong material, which successfully resists strong mechanical stresses. Soil movements will not affect the integrity of the chamber, cracks on its walls will not appear. The service life of a well-equipped concrete structure is several tens of years.
  • A very significant mass. Reinforced concrete has a large weight, which prevents the ascent of the chamber with increasing groundwater levels. For the same reason, the concrete caisson does not require additional fixing in the ground during installation.

Specialists pay attention to the fact that concrete chambers have many disadvantages. First of all, you need to understand that concrete is a hygroscopic material. It absorbs moisture very well, which penetrates into the chamber and destroys its walls. That is why in order to ensure a long service life of the structure, high-quality waterproofing works should be carried out.

Only high-performance, modern materials should be selected for processing. Particular attention is paid to the joints of the rings, the connection area with the concrete base and the place where the casing passes through the bottom of the caisson. Practice shows that it is very difficult to achieve complete waterproof design.

Another drawback of the concrete chamber is poor thermal insulation. To ensure temperatures acceptable for the operation of the equipment, it will be necessary to insulate the container.

The heavy weight, as in the case with a metal caisson, is an advantage and a disadvantage of the design. Installation of concrete rings is impossible without the use of special equipment, transportation is also difficult. All this significantly increases the cost of installing the caisson, while the price of the rings is relatively low.

Concrete caisson
The concrete structure is heavy, which may eventually lead to its upsetting and damage to the pumping equipment

In addition, the heavy weight of the camera negatively affects its operation. Over time maybe gradual subsidence of the device, which will inevitably lead to deformation of the equipment installed in it. The presence of a large number of shortcomings makes concrete caissons little in demand. They are increasingly preferred by other options.

Similar advantages and disadvantages are made of brick structures. True, its construction takes much longer, but in construction it is possible to use broken and used material.

For the manufacture of structures, a concrete base is equipped, on which walls are subsequently erected from brick, and a ceiling with a lid is mounted on them. There are two ways to equip such structures: with and without backfill.

The first involves digging a pit, the size of which exceeds the future caisson. After the walls of the chamber are laid out and dry well, the voids are filled with soil. In this case, there are no empty spaces behind the walls of the caisson in which rain water can be poured.

The option without filling involves the preparation of a pit, the size of which exactly corresponds to the future design. When laying, the bricks are adjacent to the wall, however, there are no guarantees that there will be no voids behind them. The first option is considered more time-consuming, but also more high-quality and durable.

The advantages of brick caissons include:

  • High reliability and durability. Properly erected brick wall is capable of withstanding serious mechanical influences. It is strong enough to resist possible movement of the soil. In addition, a large mass will not allow the structure to float to the surface, additional fixing during installation will not be required for it.
  • Relatively low thermal conductivity. Walls made of bricks do not conduct heat well, therefore they are distinguished by good resistance to low temperatures. Such caissons retain heat, so additional insulation of the structure is required only in areas with very severe winters.
  • Significant dignity - profitability. The cost of a brick camera, especially if it is composed of used material, cannot be compared with plastic, concrete or metal counterparts. The price of a brick caisson is much lower, which is very attractive for owners of wells.

Today, reinforced concrete and brick structures are increasingly giving way to metal and plastic counterparts. The delivery of positions is justified not only by the efficiency of installation, but also at the price of structures fully prepared for installation.

Caisson cover
Previously, there were popular cast-iron hatches, which now replaced the polymer ones - they are lighter, warmer and cheaper than the traditional metal version

Option # 2 - metal caisson

This, in fact, is a large box made of metal, into the walls of which are threaded bushings for passage of communications.Most often it is made of sheet metal, the optimum thickness of 3 - 4 mm. The best option is stainless steel. But it seriously raises the cost of construction. Sometimes there are more interesting structures made of aluminum.

The metal caisson is quite simply arranged, reliable. Easy to install, it serves for a long time. Very robust construction, with certain skills and the presence of a tool park can be made independently. Requires mandatory quality insulation.

When choosing or designing such a device, it is important to pay attention to its shape. Ideally, it should be such that there are as few welds as possible and they are performed as efficiently as possible. The slightest defect in the seam will lead to a subsequent loss of tightness of the caisson.

The use of a metal container is due to a number of advantages:

  • High strength and flexibility. Steel is a very strong and hard metal, which guarantees the integrity of the caisson casing for any, even the most significant ground movements. The flexibility of the material prevents the occurrence of cracks in the structure. Tanks made of plastic in this greatly lose the metal.
  • Long term of operation. Practice shows that the average life of high-quality metal caissons is about 50 years. This is quite comparable with the life of the well itself. Thus, a competently installed and properly operated tank will be enough for the entire period of functioning of the water supply source.
  • Too much mass. A heavy metal chamber is resistant to soil heaving. It does not need to be additionally fixed during installation. Under no circumstances will such a caisson squeeze to the surface. Moreover, it will not come up on its own, which happens with poorly fixed plastic counterparts.
  • Necessary and sufficient tightness. Well-equipped metal caisson is tight. It reliably protects the equipment located in it from the overhead water and from groundwater.

There are metal products and disadvantages. The most significant - susceptibility to corrosion. To avoid troubles, regularly cover the walls of the chamber with a fresh protective layer of paints and varnishes. From the inside it will be very simple to do, but from the outside it is almost impossible.

Both the internal and external surfaces of the chamber are processed. Moreover, at least two or three layers of paint are laid on the seams. Products made by themselves should be processed in the same way.

Another minus is high thermal conductivity. This makes it necessary to equip an additional insulating layer not only for the cover, but for the entire structure.

Metal caisson
Due to the heavy weight of the metal chamber, its installation is carried out only with the involvement of special equipment

Significant weight, which relates to the advantages of metal caissons, can also be attributed to their disadvantages. The impressive mass of the structure seriously complicates its transportation and installation, which is often impossible without special equipment.

The cost of steel products manufactured in the factory is higher than that of plastic counterparts. Therefore, you can find a large number of metal caissons, made at home, for the quality of which it is impossible to vouch.


Metal caisson
The shape of the metal caissons should be such that there are as few welds as possible. They become a potential source of danger of tank depressurization
Metal caeson
Even if the caisson is welded from stainless steel, it needs a primer and waterproofing surface.

Although welded seams are of good quality, they can crack when metal deforms. Therefore, even if the metal caisson is made of stainless steel, it still needs waterproofing. Ferrous metal is waterproofed necessarily.In this case, even if the insulation is glued very tightly and does not allow water to pass through, it is not regarded as waterproofing.

Simply put: first to the walls insulate on the outside - foam glass, extruded polystyrene foam or something similar - fibrous materials will not work here in any way. Then the structure is pasted over with hydroisol or similar material.

Option # 3 - plastic caisson

The most modern can be considered caissons made of polymers. Their plus in the low cost, ease of transportation and installation, durability. Plastic has good thermal insulation characteristics, and therefore is often used without additional thermal insulation, it does not need protection from underground water.

Three types of polymers are used to produce such caissons: polyethylene, polypropylene and fiberglass. For the manufacture of plastic containers can be used in two ways:

  • Extrusion welding. A dense and durable seam is formed under the pressure of hot air. It is especially effective when working with corrugated surfaces.
  • Rotational formatting. The result is cast containers with a one-piece housing. There are no seams, which ensures complete tightness.

Plastic chambers usually consist of two parts: over-casing and coffering. The first may have a smaller diameter. A distinctive design feature is a crimp sleeve, which ensures the tightness of the casing joint with the caisson.

Tanks can be equipped with special nozzles designed to enter cables and water pipes. Plastic downhole caissons have many significant advantages:

  • High corrosion resistance. Plastic is not subject to the destructive effect of corrosion, which allows the containers made from it to serve 50 years or more. In addition to this, the cameras do not need additional anti-corrosion treatment by special means. This saves money and time for their owner.
  • Complete tightness. The chamber made of polymer is completely sealed. For technological holes, special accessories have been developed that provide complete protection against moisture. Thus, additional waterproofing of the water-pressure side of the structure is not required. Whereas for caissons made of other materials, for example, reinforced concrete, this is a prerequisite.
  • Light weight. The design is lightweight, which greatly simplifies the process of its installation and transportation. The installation of a plastic caisson can most often be carried out without the involvement of special equipment, which can significantly save. This is not possible when installing a concrete or metal structure.
  • Sufficient rigidity of the tank. The manufacturer has the ability to vary the thickness and shape of the walls in plastic caissons, creating structures with a given stiffness. Models with internal stiffening ribs that increase the strength of the tank are available. By the way, you can pick up modifications with a reinforced base, designed to work in conditions of high groundwater levels.
  • Good thermal performance. Plastic is characterized by low thermal conductivity, therefore, in most climatic zones, the walls of the caisson will not need to be additionally insulated. Only the lid of the tank needs protection from the cold. If the caisson will be operated in areas where severe frosts are possible, it is worth insulating its walls.
  • Possibility of equipping with additional elements. Manufacturers of plastic containers offer many items that will make the operation of the caisson convenient. This can be an additional internal staircase, a special shelf for insulation for the lid, a folding above-ground part that facilitates the descent into the structure, and much more.

Two of the disadvantages of plastic containers are worth noting. The first - deformation susceptibility. To level this disadvantage, you should select a caisson for your type of soil. On sale you can find various modifications with wall thicknesses from 10 and up to 40 mm.

In addition, you can replace the external soil backfill with cement filling. Its width can vary between 80-100 mm around the entire perimeter of the caisson. Another option is backfilling with a sand-cement mixture. Experts recommend using a 5: 1 ratio.

The second drawback is plastic buoyancy chambers. You can get rid of it by equipping a concrete pillow at the base of the tank. After mounting on a concrete base, it will be necessary to fix the plastic structure, which will prevent it from being pushed out of the ground. All these measures increase the cost of installing such caissons.

Plastic caisson for a well
Ribs on the caisson can not serve as protection against crushing by soil, which tends to expand when frozen

Positive and negative sides of plastic caissons:

Option # 4 - polymer sand caissons

Relatively Recently Available Prefabricated polymer sand wells became a great option for arranging caissons. The capacity is assembled from several rings, a cone-shaped cover with a hatch and a bottom. It is made of a modern composite material, which includes sand and plastic.

The rigidity required for the operation of the tank is achieved by adding sand to the matrix made of polymer.

Polymer sand well
Polymer sand box is assembled from several elements connected by the locks of the “thorn-groove” system

Polymer sand cameras have a relatively low cost and have many advantages:

  • Resistance to external influences. The composite material is not susceptible to corrosion, does not enter into chemical reactions, and has high strength. It successfully resists mechanical stress, is frost-resistant and has a very low coefficient of moisture absorption.
  • Extremely easy installation. The design is available in the form of elements equipped with spike-groove lock joints. This allows you to quickly and efficiently assemble the container of the desired size. To install it in place, special equipment is not needed.
  • Light weight of individual elements. The weight of each of the parts for assembling the polymer sand structure does not exceed 60 kg, which makes it possible to assemble the camera together with an assistant. Transportation of rings and other elements of the caisson can be carried out by a trailer to a passenger car.
  • Ensuring perfect tightness. A properly assembled polymer sand chamber is completely sealed. To make technological holes in its walls, ordinary household tools can be used. After the pipes are inserted, the holes must be sealed with any suitable composition.
  • Long term of operation. The manufacturer guarantees that his product will last at least one hundred years without changing its properties. Since polymer-sand products are still quite “young”, this has not been verified in practice.

However, it is impossible to guarantee tightness at the joints of the structural elements of the tank. Therefore, experts recommend that before starting the assembly of the camera, be careful and grease future joints with sealant or usually bituminous mastic. Such a compound will better retain moisture.

A bit about polymer sand well, which can be used as a caisson:

General installation recommendations

From an engineering point of view, installation of a caisson for a well is required for equipment placement and protection well head from damage, entry into the stormwater intake zone and pollution.

A caisson for a well is much more profitable from the standpoint of operating costs - unlike ground structures, it usually does not require heating (provided that it is below the level of the estimated freezing depth). Although there can be no other option - if he stands higher, he will simply be squeezed out in the winter.

A buried caisson can also squeeze out soil. Especially in cases where the site has problems with a high occurrence of the top of the boat. Therefore, it is recommended to “anchor” not only light plastic, but also more stable metal systems. Technically, this is very simple. Under the caisson for the well, a concrete slab is poured, to which the bottom of the caisson is attached using anchor bolts.

In high unsinkable areas, you can do without a concrete base - a fairly good sand cushion. But here, all the same, the presence of a heavy plate under the caisson does not hurt. Therefore, it is better to always plan it, away from the geological features of the site. In any case, the caisson is placed strictly upright - compliance with this condition is mandatory.

The height of the structure is about two meters - this size allows you to conveniently work, and place equipment, and deepen the caisson below the freezing depth.

Caution for painting the caisson
An important point: when painting the caisson from the inside, the exact same rules apply as when cleaning the tanks - even with regular ventilation

Even if all conditions are met, it is good to lay in the main pipes heating electric cable - just in case of force majeure.

The electric cable, feed pump and automation, do not lay directly in the ground. He does not need a deepening, like pipes with water, but he still needs to be protected. It has double insulation, but this is not enough. It is better not to use corrugation, which is very popular in outdoor applications, for these purposes. An HDPE pipe is best suited.

A pipe with an electric cable is laid shallow underground - about 30 cm from the surface. The considerations here are simple - the frost is not terrible, but just in case, you need to take care that communication is not damaged by accident. The guideline is simple: we dig deeper than a bayonet on a shovel.

A pipe with water is buried deeper - below the freezing depth. Entering the house on the surface is possible only if the section of the pipeline is insulated from the level of seasonal freezing to the point of entry into the construction. It is better to lift the equipment above the caisson floor. Slightly, but necessary. In case of flooding.

All electrical devices in the box must be grounded. And it would be nice to introduce into the electrical circuit RCD. Security is never superfluous. Rather, it may not be enough.

The casing of the well passes into the caisson through the sleeve, which is slightly larger in diameter. For example, given the current assortment, a common casing with a diameter of 133 mm will require a 146 mm sleeve.

The well pipe should not be flush with the bottom of the chamber - always slightly higher. Exceeding within 40 - 50 cm. In case there will be flooding.

The sleeve and siege pipe at the junction are sealed. A head is put on the well - a special tight cover in which there are openings for the cable of the submersible pump and the passage of the PND pipe from the pump. The power cable of the pump is also attached to it. The cover protects the wellbore from dirt and accidental debris.

The entrance to the chamber of the caisson is traditionally designed in the form of a hatch. The design depends on personal preference. In any case, the preferred option is with two hatches - just for reasons of heat conservation.

The hatch is placed above the well
The hatch is placed above the well for reasons of ease of installation and operation.

The exit under the well pipe breaks, as a rule, in place. It does not have to be clearly centered. It is entirely permissible to displace it, to make it asymmetric. But here we must remember that the well exit and the caisson hatch must be coaxial - this is very convenient when repairing and installing equipment. Simply put: it is advisable to install the entrance hatch directly above the head of the well.

All about installation and connection

The installation procedure, in general terms, is similar for all types of caissons. Although there are features, which will be discussed below.

The pit for the caisson is chosen at least 30 cm larger than the caisson itself. This will help and more accurately establish it, adjusting the coincidence of the well pipe and the sleeve for its passage. In addition, this will allow insulating the walls or strengthening, as the plastic structure requires.

As already mentioned, the well casing is cut to reflect the future height of the chamber floor. The bottom of the pit is closed with a sand pad 20 - 30 cm thick. Sand filling is spilled with water for compaction. A concrete slab with steel mesh reinforcement is cast on top of the pillow.

You can place anchor bolts on it in advance to secure the caisson. But there is a great chance to make a mistake. Therefore, it is much more convenient to first install the caisson in place, and then drill holes for fasteners in the plate.

Now there are a lot of options for fasteners expanding and wedging in the holes, and therefore there are no special problems to choose something suitable.

How not to do
The photo shows how to not do it - thermal insulation mats collect water and it stops working very soon

Now a little dwell on the features of a particular design scheme.

Installation of a caisson from concrete rings

Technology is not much different from installation well rings. Only to a much shallower depth. The rings are fastened together by steel plates - in case of soil shifts.

The seams between the rings are filled with cement mortar and iron - smeared with a clean cement mortar without adding sand or other thinning additives.

Concrete still lets water through, albeit not intensely. Therefore, in advance it is necessary to take care of the waterproofing of the walls of the caisson. Often for these purposes, roofing material or polymer films are applied, glued with the help of bitumen mastic. The method has the right to life, but it is better to use reinforced materials glassisol or hydroisol. Or the like.

Concrete well resists cold and freezing, but still its regular characteristics are not enough. Additional insulation is required. It should be borne in mind that the insulation used should not absorb water - otherwise it will be useless. And resist soil pressure - over time, soft heaters can compress the soil to the thickness of a paper sheet.

Therefore, preference is given to the most dense and durable grades, often to various varieties of stove insulation. You can advise foam glass - but this is a very expensive option. Extruded polystyrene foam will be a more affordable insulation. Or, as it is called in abbreviated form, EPSP.

The cheapest insulation is likely to be polystyrene.It is easy to work with him and its increased combustibility will not play a role when located in the ground. But it resists compression worse and is not very durable - in a few years it will have to be changed.

Not only the walls are insulated, but also the ceiling. But this is much easier than insulating a wall. We only take into account that the insulation should not stand out beyond the perimeter of the caisson - otherwise it will simply be torn off when shrinking - the design is still quite heavy.

Another interesting point. Often there are recommendations for concrete caissons not to make a bottom. That is, install the rings directly on the sand cushion and gravel drainage. The motivation is simple: in the event of condensation, it will go into the soil.

Or the second version of this solution: do not fill the seam with cement mortar between the lower ring and the concrete base. The reason is the same - to allow the possibility of condensate to escape.

Concrete caisson insulation
Insulation of a concrete caisson is not an easy task, for the solution of which the shell principle is suitable

Such designs are difficult to recommend for repetition. Walking because this scheme would work only on a high dry area. In other cases, a hole two meters below the surface of the earth will do its job - the caisson will be flooded at least once a year. And, therefore, will not fulfill its role.

The condensate problem is solved by normal insulation. In an extreme case, we simply introduce ventilation into the structure - as in a cellar.

The absence of a concrete base under the rings is completely unacceptable - due to the small footprint. In other words, there is a risk of large shrinkage. Which, in turn, is fraught with deformation of the incoming pipes. The principle of the approach is simple: everything should serve for a long time and reliably. The fewer adjustments and interventions required subsequently, the better.

The passage of pipes through the walls is insulated in exactly the same way as the inputs through the foundation of the house - cement mortar and bitumen mastic from the outside.

Well head
The well is protected by a special head, which provides all the necessary

Installation of a metal box

Installation of a metal caisson necessarily requires a cast base plate and anchoring. Before installing outside, the box of the caisson is glued with waterproofing. Primed inside. This is a must even for stainless steel. Necessarily warming. A slightly different way to skip communications.

The casing of the well is simply passed into a sleeve which is hermetically welded to the bottom. For the rest of the bushings, bushings are welded into the walls. They simply screw the necessary fittings into them, thus leading the water lines (to the general water supply, for watering the garden, to the pool and so on) and by passing the power cable to electric pump.

Usually everything happens in this sequence:

  • Digging a pit under the caisson.
  • The base is being made - a sand cushion and a concrete base plate.
  • Cut to the size of the well casing.
  • A caisson is placed over the pit on the bars or channels and carefully exposed until the well pipe and the sleeve coincide.
  • The caisson is finally installed in its regular place.
  • Digging auxiliary trenches for water supply to the house and others.
  • All communications are connected.
  • Insulation and waterproofing is hung.
  • Caisson is closed with soil - it is buried.

In this scheme, there may be additions and permutations, depending on the conditions of the site and tasks. But digging trenches under the liner to the caisson is best done after installing it - just jumping at that moment through the extra ditches and pits is not entirely handy.

Installation of a plastic caisson

In general, the process is very similar to the manipulation of the metal option. The difference is that when sealing the joint of the casing with the sleeve, not welding is required, but glue for pvc.

And the passage of pipes through the walls is carried out not through threaded sleeves, but through special couplings, which are then closed with sealing covers.

An important feature is that waterproofing and insulation are not required, but mandatory protection against crushing by the soil is needed. It is done simply. The gap between the walls of the pit and the caisson is filled concrete mass. Do not need a high strength composition. A solution of 5: 1 is enough, which means: 5 parts of filler and 1 part of cement. As a filler, a mixture of sand with crushed stone.

A necessary measure, even if there are stiffeners on the polymer case. But all these troubles are not so high, when compared with the previous options. In addition, such a concrete shell makes the entire structure stronger and more resistant to extrusion. Which affects the overall service life.

More details in the photo galleries:

Conclusions and useful video on the topic

The rules for installing the caisson and placing equipment in it are slightly different. It all depends on the type of design, but in general terms it is repeated: the principle itself is important.

Caissons are an element necessary for a high-quality arrangement of a well. It is very important to choose the right device, because the operation of the entire system will depend on this. It is impossible to unambiguously determine the best caisson. This should be decided by its future owner. When choosing, you must take into account the features of the terrain, wells and your financial capabilities.

The rules and subtleties of installing a caisson for a well are not so numerous. Even if the developer is not confident in his own abilities and will not deal with the problem on his own, knowledge of the basics will allow him to control the work performed on the site by the contractor. After all, the comfort of living in the future depends on the quality of their conduct.

Seriously thinking about installing a caisson? Or maybe you've already done this kind of work yourself or have valuable knowledge that you want to share with visitors to our site? Please share your experience, leave your comments at the bottom of the article.

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Visitors Comments
  1. Of course, a plastic caisson is a reliable and durable option. And for those who do not need to save money, this is the best choice for arranging a well. For budget suburban housing or a small summer cottage, when the price matters, I would recommend concrete rings. The main question is that the rings must be of high quality. Then they are enough for your century. And the issue price will be much lower.

  2. Maxim

    Previously, in order to fill in a monolithic reinforced concrete caisson, it was necessary to arrange the formwork, install a reinforcing skeleton. We needed information on the physicomechanical properties of the soil, for pouring concrete there should have been grades no lower than 400. Now plastic or metal structures simplify our lives. Nevertheless, it is always necessary to observe a number of rules that are common to the device of all caissons so that they serve for a long time and do not cause inconvenience during operation.

  3. Victor

    I consulted about the installation of the caisson, they told me that it would really be better with him. I took it with a heat-insulated lid, since in winter there are periods with severe frosts, so that nothing freezes, I decided to play it safe. Well, and of course, from plastic, it does not freeze, condensation does not form, metal in this respect is significantly inferior to polymers. This pleasure cost a little more than 22 thousand rubles. I just didn’t think at once, and then it was too late, the design turned out to be not very convenient in operation, there are no loops for the lid and sleeve for the casing. So pay attention to this.

  4. Sergei

    Tell me on plastic caissons - how are they with reliability? Can he stand it if I have a playground nearby where I park the car?

    • Expert
      Nikolay Fedorenko

      Hello, Sergey. Plastic caisson is a fairly robust construction. If you take into account that usually plastic caissons for wells are buried in the ground, filled up and poured with concrete, then you can safely park a car nearby.

      If the site is concreted and is not in the immediate vicinity of the plastic caisson, then there is nothing to worry about. How far is the parking area?

      And one more clarification, if the car is not a car, but a truck, then the site is better to move.

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  5. Anatoly

    I saw a lot of plastic caissons, just flat, even there are no stiffeners, and there are no signs of reinforcement of the walls, they will gradually squeeze them out of the ground with ground water. I even squeezed out iron, put a plastic Bio-s, with lugs, stood for two years, did not rise, the walls were reinforced with iron rings.