How to insulate a concrete well: a way from the most severe frosts

Winter is just around the corner, which means it's time to work on the insulation of everything that can freeze. One of the problematic objects in frosty winters is a well, especially when the pumping station is located directly in it. A frozen pump is half the trouble, a broken (thawed) water supply system is a real problem. Read how to insulate a concrete well so that it functions even in the most severe frosts.

Where to begin

Any business starts with a plan and this is no exception. For effective insulation, it will be necessary not only to create a shell of EPS or foam, but also to make a warm blind area. It is necessary to insulate both the upper (visible) part of the well, and deepen to the freezing point. In central Russia, this depth is 1-1.2 m; in the southern regions, this point may be at the level of 0.6-0.8 m.

Necessary materials:

• foam or EPSP with a thickness of at least 100 mm;
• polyurethane foam;
• insulation glue;
• plaster mesh;
• thin wire;
• sand and crushed stone of fraction 20/40 mm;
• plaster solution;
• concrete solution.

Excavation

It all starts with earthworks. First you need to remove the soil for the blind area. The optimal width of the blind area for a well is 0.6-0.8 m. The deepening under the blind area must be made 0.4 m. K word: the blind area is a necessary element and if it is not done, the forces of frost heaving will squeeze out insulation.

When the trench for the blind area is ready, it is necessary to excavate the soil to the required depth at the walls of the well. The depth of the excavation is determined by the region and the freezing point. As already mentioned above: for the southern regions - from 0.6 m from the ground surface; for central areas - from 1 m. The width of the recess is 0.15-0.25 m. The width should be sufficient to work with a polyurethane foam gun.

After excavation, the concrete surface of the ring must be cleaned with a metal brush and the dust removed. There should be no dirt, paint and other things on the concrete.

Work with insulation

Next, a heater is prepared. You can use both extruded polystyrene foam and foam. The optimal insulation thickness is 100 mm.

The material must be cut into strips 200 mm wide. Standard EPSP sheet has dimensions 1200 * 600 * 100 mm. Thus, 3 pieces of 1200 * 200 * 100 will turn out from it. The required number of such strips depends on the diameter of the ring.

There is one nuance in the material consumption, depending on the freezing point and the height of the well. If the freezing point is at a depth of 0.6 m, and the height of the well is also 0.6 m, the cut sheets are sufficient in height. Here, the total height of the insulation will be 1.2 meters, which corresponds to the size of the EPSP sheet.

In the case when the depth of freezing, and, accordingly, the insulation under the ground is 0.8 m, and the well extends 1 m above the ground, the total height of the insulated surface will be 1.8 meters. For this, you will need sheets of 1200 * 200 * 100 mm, as well as sheets of 600 * 200 * 100 mm for the lower insulation. In general, you can cut the insulation in different ways, and choose different sheet sizes, up to 2400 mm, but this option is optimal.

Shell

When everything is ready, you need to start gluing the insulation to the ring. To do this, first, if the length of the sheets is not enough, you need to paste over the lower part, and then move on to the upper one. The sheets are glued vertically as tightly as possible to each other. When the glue sets, the cracks are filled with polyurethane foam. For these jobs, it is best to use foam with high density and minimal expansion. After the foam dries, all irregularities on the surface must be carefully cut off. The shell is ready!

Blind area 1st stage

The next stage is making a blind area. To do this, you need to create a sand pillow under it. Backfill with sand into the cut around the well. Tamp the sand and level it with the trench under the blind area. After that, cover the bottom with a layer of rubble and tamp. The crushed stone pad should be no more than 100 mm thick.

Then fill in the sand and tamp. The compacted thickness of the sand cushion should be 200 mm. Lay a thick cellophane film on the sand. Next, you need to lay sheets of high density EPSP - the same one that fits under the screed. The gaps between the sheets are filled with polyurethane foam.

Plaster

To carry out plastering work, the blind area must be covered with a film and boards so that under the weight of the master there is no deformation of the laid insulation. Next, the shell needs to be wrapped with plaster mesh and plastering. Here everyone is free to do as he wants, the main condition is that the insulation must be reliably hidden from external atmospheric influences, in particular from ultraviolet radiation, which polystyrene and foam.

Blind area 2nd stage

The final stage of the ring insulation is filling the blind area. For this, concrete is laid on top of the blind area insulation with a layer of 5-7 cm. The best option would be an inclined blind area, which will divert water from the ring.

Cap

Covers are different for everyone, but the method of insulation does not change from this. If the cover is concrete with a hatch, you can glue the EPSP sheets from the inside, foam up the cracks, and then close it with foil insulation. With a wooden lid, you need to act according to the circumstances: you can insulate the lid, and, possibly, make an airtight liner from high-density EPS and place it in the well for the winter.

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