Table of Contents
The system of autonomous water supply from discharge of unjustified luxury has turned into category of necessary devices long ago. The seasonal dacha and furthermore residential building, located in places where there is no centralized water supply system, will hardly do without well. For its drilling, especially if it is big depths, usually attract professionals. And here it is quite possible to conduct further arrangement independently and it will be necessary to begin with caisson.
Caisson: what is it?
The name “caisson” has come from the underwater fleet where it designated absolutely sealed container for works at the bottom. The constructions used in construction of surface facilities for wells also have to be waterproof, but also they have gained some additional properties. Capacity which is called caisson is used for protection well from low temperatures and hit of underground waters. In construction the equipment pumping water to the house can be placed. However, devices for water supply can be located in the basement, but it does not mean that it is possible to do without caisson.
The upper part of the upsetting well is not brought to surface, it has to be at depth about two meters. On this mark underground waters can already lie, besides their level can periodically increase, provoked by flood or abundant long rainfall. If underground waters get to well, they can not only break operation of the equipment or even to damage devices, but also to mix up with clear water. As a result to the house peculiar “cocktail” from borehole and underground water will be served that in itself is unhygienic and it is even dangerous.
One more moment: not all areas can brag of small temperature differences within year. In principle, the well can be operated during any season. However the water moving on surface in frost can freeze and spoil or break off the equipment. For ensuring steadily positive temperatures of the well the caisson is used. It has rather good heat insulation though areas with very freezing winter weather, most likely, require additional warming of capacity.
Types of caissons
The caissons intended for protection well from low temperatures and underground waters are different in the sizes, form and material of which they are made. Distinguish:
- Plastic tanks. Are issued from strong durable plastic, are absolutely hermetic. Can be the most different sizes, forms, with the openings equipped with special nipples for water pipes. Have the small weight therefore it is very easy to establish them. The insufficient rigidity of material which can lead to deformation of installation and, respectively, pipes and the equipment in it, is compensated by cement grouting 100 mm thick on perimeter established to the place of capacity. The main shortcoming – rather high cost of construction.
- Concrete caissons. Very strong and long-lasting constructions. Can be executed from concrete rings or are filled in independently. Are rather difficult in mounting, installation of rings surely requires the special equipment. The additional waterproofing owing to high hygroscopicity of material can be required.
- Metal tanks. Perhaps, the most widespread option of caisson. Can have the form of cylinder or parallelepiped. Are rather simple in installation though for mounting of construction special equipment can be also required. One of the main shortcomings – low resistance of material to corrosion therefore special processing of design surely will be required.
The plastic caisson which besides also is very reliable and long-lasting is simplest in mounting. However those who want to receive the budgetary option of capacity prefer other options which it is possible to make with own hands. Let’s dwell upon them.
Concrete construction: design and features of mounting
Before to get to work, it is necessary to decide on the construction sizes. If the equipment for feeding water will be located in caisson, the minimum structure gages has to be 1.5х1.5 m with height of 1.8 m. If devices are taken out to the certain room, for example to the cellar of residential building, then it will be possible to manage caisson of 1х1 m. It is worth to remember that in capacity it is necessary to go down from time to time for carrying out the servicing works therefore it will be reasonable to pick up such sizes of design which will allow to do it without any problem.
It is also necessary to decide on type of bottom of construction. Specialists claim that on sites where underground waters do not rise highly, it is reasonable to refuse filling of bottom of caisson solution. However if water approaches close surface, there are no other options, and the bottom of construction is filled in with concrete. In general process of arrangement of concrete capacity consists of several stages:
- We prepare ditch. Around casing pipe we dig out hole of the necessary size. We fill up bottom with crushed stone layer of at least 15 cm or we fill in with concrete. To protect construction from possible hit in it underground waters, we stack on its walls holes base film.
- We install fittings. Since bottom we knit grid from armature with step of 30х30 cm. Height of design can be different, it depends on how it is going to fill in construction. It is the best of all to do it in one step that, however, not always perhaps and then filling happens step by step. If walls of caisson are filled in entirely, armature has to reach the upper edge of hole if step-by-step concreting is supposed, height of grid is defined by the expected height of the first filling.
- We mount timbering. She can be collected from old boards and bars, having brought down from them boards of the necessary size. It is the best of all to fit the turned-out parts polyethylene film, having attached it to the basis the construction stapler. As practice shows, it is much easier to remove the timbering prepared in such a way from the stiffened concrete.
- Filling. In the prepared design concrete is filled in. In case of step-by-step filling on the stiffened material the following block of armature is mounted, the timbering is established and filling and so is carried out until the wall of the necessary height turns out.
- We bring pipes in caisson. After concrete completely dries out, the perforator we carry out the openings in construction walls intended for leading of water pipes. Best of all on sites of pass through concrete to establish metal sleeves, diameter there are slightly more pipes, and already to insert pipes into them. For sealing of the site all slots between sleeves and concrete are closed up by solution, and between pipe and sleeve – polyurethane foam.
- We establish timbering for cover. The design is carried out in the form of horizontally oriented wooden board laid on bars. It is also reasonable to fit it film. Material for timbering has to be rather strong to sustain solution weight. We begin with installation of bars. We expose them vertically on construction bottom on specially laid boards. From above horizontally we put some more bars. We fasten construction with self-tapping screws. On the turned-out basis we fix boards. We do not forget about opening under the hatch on which it is necessary to establish wooden box. The collected timbering before filling can be strengthened still from below bars.
- We mount armature. That the cover has turned out stronger, it is possible to start up on construction perimeter armature with step of 5х5 cm. In design there will be enough step of 15х15 cm. If there is need, metal pipes conclusions for watering hose or ventilation are attached to armature.
- We fill in cover with concrete.
- We mount timbering for installation of box under the hatch. The construction rises over cover level approximately on 30 cm. In ready timbering we fill in concrete. After drying we install the hatch.
The design is ready. If necessary caisson it is possible to warm and process its walls the waterproofing structure. It is possible to simplify rather difficult mounting of construction, having established ready concrete rings in the prepared hole. However such option will demand attraction of special equipment whereas when filling walls it is possible to manage, literally, make-shifts. Besides the construction from concrete rings will be much more expensive. One more similar option which is widely used owners of wells – arrangement of brick construction. It is very similar to concrete with that difference that its walls are executed brick. The laying is begun with the bottom which is filled in with cement slurry and conducted up to ground level where equip from above concrete cover with the hatch.
Metal design: we collect and establish independently
Many owners of wells choose such option of caisson, most often making it independently. Really, such construction is very practical. It is steady against pressure, hermetically and has the long term of operation. Independent production and mounting allow to save means significantly. However such decision has also shortcomings about which it is necessary to know. Material is subject to corrosion which centers it is very difficult to eliminate from outer side of design. The inside face also requires periodic anticorrosive processing. When mounting caisson, most likely, the special equipment for installation of design in ditch will be required.
For production of metal capacity it is required:
- Pipe about 20 cm long which diameter is close to the outside diameter of casing pipe. The sleeve for passing of column will be made of it.
- Pipe about 60 cm long and diameter corresponding to hatch mouth.
- Sheet steel 4 or 5 mm wide.
- Pipe which diameter will be sufficient for the device of capacity and about 2 m long.
It is the best of all to carry out works together with the assistant. From tools the electric drill, the Bulgarian and the welding machine is required. It is the best of all to lay out the prepared metal on boards or bars, so will move it more simply and it will be possible to save from dirt. Works on production of metal caisson take place in such sequence:
- We prepare the bottom and cover of caisson. From the sheet of steel it is cut out two circles of the necessary diameter. In the bottom we cut out opening under sleeve, and in cover – under nipples of cable and conduits.
- We smooth out inside and outer surface of pipes under capacity and under mouth. Also we smooth out sheets of which the cover and bottom will be made. We remove dirt and rust. For simplification of process we use the round metal brush inserted into drill cartridge.
- We wipe the cleaned surface, removing dust, and we prepare internal part of pipe for priming. We apply primer, watching that places of future welding seams remained clean.
- We weld pipe which will become capacity basis, to the bottom. It has to support approximately on 2 cm limits of walls of caisson.
- We weld top cover and nipples.
- The reservoir is stacked sideways, in top cover we cut out opening under the hatch.
- We weld pipe for installation of the hatch. We establish design and we put on it cover.
- We process and smooth out all seams.
- We make internal and external waterproofing of caisson.
The construction is ready, it is possible to start its mounting. It should be noted that the metal design can be any form. If there is no opportunity to pick up pipe which will become capacity basis it is quite possible to weld caisson in the form of parallelepiped. Only nuance: the more in construction of seams from welding, the potential threat of corrosion is higher. Therefore it is better to minimize their extent.
Mounting of metal caisson is carried out in several steps:
- We prepare hole under capacity. We dig out ditch around casing pipe, choosing diameter so that the distance from construction walls to the earth made at least 10 cm. We pour bottom of hole sand and we stack on it concrete pad. Well we pressurize slots around the column passing through concrete. We cut off casing pipe at the level of the upper edge of hole.
- Preparation of caisson for mounting. Over hole we lay bars on which we establish capacity. We put on sleeve in day of design casing pipe. We control that axes of column and sleeve matched.
- Descent of capacity in ditch. Carefully we remove bars and it is accurate not to damage corrosion-resistant coating of walls of caisson, we lower it in hole. Performance of this operation, most likely, requires the special equipment. The mouth of construction has to rise over surface approximately by 15 cm.
- Lining. By means of level by wedging by bars we level design bottom strictly down.
- Institution of communications in capacity. In construction we get pipes and cables. We pressurize all sites which can pass moisture in design.
- We fill up the reservoir. Specialists advise before starting charge, to fill in construction with the melted sheet asphalt.
The caisson is necessary for each well. Plastic tanks are very practical and simple in mounting, but their high cost makes them not quite available to most of owners of wells. If desired it is possible to equip construction with the hands and with the minimum monetary expenses. It is necessary to choose only correctly type and to carefully consider the project of design. Of course, independent production and mounting of caisson quite complex business, but if it is correct to execute everything, result of efforts will become the clear water moving from smoothly working well.