Ways to properly insulate a concrete well

Concrete wells must be insulated at the construction stage, regardless of their purpose. Uninsulated plumbing, technical or water wells will freeze through, which will damage equipment, pipelines, and the inability to use communications in severe frosts. In order to effectively insulate a well from concrete rings, it is necessary to select a suitable heat-insulating material and observe the technology of its installation.

Functional purpose of wells

Concrete ring wells are built for different purposes. Due to the specificity of concrete, which has high thermal conductivity, they freeze at low temperatures. By functional purpose, structures are distinguished:

• For water supply. Needed where there is no central water supply. In the ground, a deepening is made to the aquifer, the casing of the mine is performed with concrete rings.
• Technical. Equipment is placed in the mine, protected from ground collapse by concrete rings. For example, they equip a caisson for a well.
• Plumbing. These include septic tanks made of concrete rings for a summer residence or home. Rings are also installed in the mine, a drainage layer is poured on the bottom and sewage drains are diverted into this pit.

Shallow wells located above the level of soil freezing should be insulated as efficiently as possible, even if it is a dry technical mine. The service life of equipment operating at low subzero temperatures is reduced. If the equipment or water mirror is located below the freezing level of the soil, there is no urgent need for insulation.

Freezing reasons

When central water supplies were rare, water supply wells were made of wood. The thermal conductivity of this material is lower than that of concrete, so they did not freeze even during prolonged frosts. Concrete has a high thermal conductivity, so the concrete rings freeze, like the surrounding soil. In addition, wooden houses were often built over the wells, which prevented direct contact between frosty air and water. The difference between water and air temperatures was up to 30 ° C.

Whether an uninsulated mine will freeze depends also on the depth of soil freezing, typical for a given region. In the southern regions, the problem is less relevant, since here the freezing depth is no more than 0.5 m.In temperate latitudes, the soil freezes to a depth of 1.5 m in winter, and even deeper in the northern regions, so residents of these regions need to take care of high-quality insulation.

Do-it-yourself insulation methods

If the thermal insulation work was not carried out during the construction phase, a number of preparatory steps must be taken before the direct thermal insulation: dig a trench around the well of such a width that it is convenient to install the thermal insulation materials. The depth of the trench should exceed the calculated freezing depth by about 1 m.

Warming of a well made of concrete rings is performed in various ways.To avoid large-scale earthworks, sometimes they are limited to the construction of a wooden house located above the mine, making a cover or finishing the head with heat-insulating material. Underground insulation is the most effective, but laborious.

External ground insulation

External ground insulation refers to the insulation of the basement (upper concrete ring) and the blind area. When insulating the basement, it is advisable to go a little deeper into the ground, digging a trench up to 1 m deep and 30 cm wide.

1. The walls are cleaned of soil.
2. The base is treated from the outside with a coating waterproofing.
3. Insulation for the well is cut into strips or a shell of the appropriate diameter is used.
4. The basement is glued around the perimeter with facade glue, polyurethane foam.
5. The base is painted with oil paint.
6. A membrane, film, roofing material or other materials with water-repellent properties are fixed on top.
7. Between the insulation and the walls of the mine, drainage is poured - expanded clay, crushed stone, gravel. These materials are also effective as heat insulators.
8. A ground layer 25-30 cm thick is made on top.
9. The facing of the head is carried out with bricks, tiles, stone, wooden boards.

The blind area is made to a height of 20 cm by pouring concrete around the well. The hardened concrete is finished with facing materials.

External underground insulation

Underground insulation includes insulation of the entire underground part of the structure. It is especially important to qualitatively insulate a well of concrete rings for the winter above the freezing level of the soil. For the thermal insulation device you will need:

• insulation;
• polyurethane foam;
• concrete primer;
• liquid waterproofing;
  
• polyethylene film;
• wire;
• construction glue;
• Decoration Materials.

All the necessary work is performed step by step according to the following scheme:

1. They dig a trench, the depth of which is 0.5 m higher than the depth of soil freezing.
2. Concrete rings are cleaned of soil, covered from the outside with a primer and waterproofing.
3. The rings are pasted over with strips of insulation from the bottom up, making sure that the gaps are minimal. You can use liquid foam for gluing.
4. The thermal insulation material should be 10-15 cm higher than the head.
5. Insulation joints are filled with polyurethane foam.
6. The insulation is wrapped with roll waterproofing. Fix it with wire or nylon cord.
7. They fill the trench with drainage: expanded clay mixed with gravel.
8. Arrange a blind area with a width of 0.5 m from concrete or clay. Concrete thickness - 20 cm, clay - 40 cm.
9. If a house for a well is installed, the foundation is poured.

It is recommended to trim the head with decorative material, install a well house, insulate the cover.

Insulation of the inside

Insulation from the inside is performed for dry wells made of concrete rings, i.e. technical. In a water shaft, internal insulation is reduced to the manufacture of covers that are installed in the barrel. Two covers are made, which are fixed at some distance from each other. Due to the air lock, they block cold air and protect against freezing.

Manufacturing procedure:

1. Take plywood with a thickness of 15 mm, cut out two circles from it with a diameter of 3-5 cm less than the inner diameter of the concrete of the rings.
2. The lower surface is treated with oil paint and covered with a thick plastic wrap.
3. A ventilation hole is made in the lid for the diameter of the plastic pipe (up to 5 cm).
4. The cover of the well is insulated with polystyrene or expanded polystyrene with a thickness of at least 50 mm.
5. On the sides, two rings are installed, to which a nylon cord is tied.
6. Metal brackets made from a rod with a thickness of more than 10 mm are inserted into the joint between the concrete rings at a level of about 1 m from the water mirror.
7. Place the lid on the staples.
8. The cord is fixed.
9. The second cover is installed in the same way.

This method is effective, but inconvenient with frequent use of the well, because each time it is necessary to remove the covers to collect water.

The best option is to completely insulate the outer part of the well to a depth exceeding the level of soil freezing. If you additionally install a wooden house, the well will not freeze even during the strongest and longest frosts.

Materials for insulation of wells

The range of heat-insulating materials is represented by heat-insulating materials with different properties.

Polyurethane foam

Polyurethane foam guarantees a high degree of thermal insulation, is resistant to moisture, and is not interesting for insects. The service life is at least 50 years. It has only two drawbacks: complex application technology and high cost. It is produced in the form of a liquid composition in cylinders and in the form of a mixture, which must be diluted before application, according to the manufacturer's instructions. Spraying equipment is required for work. The coating fills all gaps and recesses, no joints are formed that could serve as cold bridges. Before applying polyurethane foam, the concrete surface should be treated with a primer, and the surface of the well after finishing work should be covered with paint for outdoor use. In air, the polyurethane foam coating sets in a few minutes, completely hardens in 4-5 hours.

Polyurethane foam can only be applied within a temperature range of +15 to + 30 ° C.

Expanded polystyrene

By its properties, expanded polystyrene resembles foam plastic, but its thermal conductivity is lower, and its resistance to stress is higher. In addition, it does not deform under the influence of a layer of soil, is resistant to mold and corrosion, and serves for more than 25 years. Domestic polystyrene foam Penoplex, URSA, Technoplex, Tenzipex will cost less than similar imported insulation, but 20-30% more expensive than polystyrene. The joints of the insulation must be blown out with polyurethane foam and the installed insulation is wrapped with roll waterproofing.

To insulate the well, it is recommended to use slabs 30 cm wide. They can be laid more tightly in a circle. If the outer part is insulated, staples are used to secure the insulation more firmly.

Styrofoam

Polyfoam can be used to insulate the well both during the construction phase and after. This material demonstrates high resistance to deformation, low degree of water absorption. At cost, foam is the most affordable of all thermal insulation materials, it is easy to install. However, low-quality insulation at high temperatures releases styrenes - toxic substances that poison the environment. Another drawback is that insects and rodents are not indifferent to foam.

Foam insulation is produced in the form of a shell, which is ideal for insulating concrete wells, since its diameter coincides with the rings of the most popular sizes.

Installation instructions:

1. The walls of the well are cleaned of debris and soil.
2. The insulation is mounted on the facade glue, if necessary, reinforcing it with dowel-nails.
3. Vapor barrier is performed.
4. They bury a trench.

Wood

Solid wood is used to insulate the outer part of the well. An independent method is the construction of a log house, which is installed like a house. A well gate can be fixed between the walls.

Mineral wool is not used for insulation of concrete wells, which is explained by its low water-repellent properties. Gaining moisture, the material stops working as a heat insulator. You can use natural materials: expanded clay, linseed tow, straw.

Insulation of the well cover and pipes

Thermal insulation of the cover increases the overall effectiveness of the frost protection. It is recommended to make a wooden well cover from plywood or tightly fitted wooden planks.It is made of two layers of material with a thickness of at least 18 mm, insulation is laid between them. It is most correct to use polystyrene and expanded polystyrene for this purpose. The reinforced concrete cover also needs to be insulated. The heat insulator is fixed with dowel-nails on concrete or with glue for outdoor use.

It is necessary to take care of the insulation of the water supply pipe, the sewer pipe, the place where the pipe enters the house. For this purpose, a polyurethane foam shell and a heating cable are used.

Insulation of a well made of reinforced concrete rings must be performed even when using it in the warm season. When water freezes, it expands, due to which concrete rings are displaced, diverged or cracked. Also, during freezing, hoses and pipes are destroyed, and the service life of the equipment is reduced. Thanks to a wide range of thermal insulation materials, you can choose a heater that is suitable in terms of properties and price.