Owners of summer cottages often face the problem of storing perishable goods products during periods of lack of constant power supply. An alternative to electric units is earthen refrigerator, which uses the natural coolness of the lower layers of the soil. This time-tested solution allows you to store vegetables, fruits, dairy products and even meat for a long time without energy costs.
The operating principle of such a storage facility is based on a stable soil temperature at a depth of more than two meters, which stays around +4...+8 degrees all year round. Thermal stability is achieved due to the absence of direct sunlight rays and insulation from atmospheric fluctuations. A properly equipped pit works as a natural air conditioner, creating ideal conditions for long-term storage of reserves even in the summer heat.
The creation of such an object requires careful planning and adherence to construction technology to avoid flooding with groundwater or the appearance of mold. In this article we will analyze all stages of the work, from choosing a location to the final finishing, which ensures the durability of the structure.
Selecting a location and soil analysis
The first and most critical stage is determining the location for the future storage facility. You should not dig a hole in lowlands where water accumulates after rains, since the risk of flooding in such places is maximum. The ideal option would be a hill or a flat area with deep groundwater. groundwater.
Before starting excavation work, you need to find out the level of soil freezing in your region. Temperature in the storage directly depends on how deep you immerse the container or arrange a niche. If the bottom of the pit is above the freezing level, food may freeze in winter and spoil in the summer from the heat.
It is also important to consider the distance to the trees. The root system of large plants can damage waterproofing or even the walls of a structure over time. The optimal distance to the trunks is at least 3-4 meters.
⚠️ Attention: Before digging deep holes, make sure that underground communications are not laid in the chosen location: gas pipes, electric cables or water supply. Damage to a gas pipe can lead to catastrophic consequences.
The composition of the soil also plays a role: sandy soils easily crumble and require mandatory strengthening of walls, while clay soils hold their shape better, but can create problems with drainage.
Necessary materials and tools
To build a reliable storage facility, you will need a set of construction materials materials that provide tightness and strength. The basis is most often concrete, brick or ready-made plastic containers that perform the function of caisson.
If you plan to use an old refrigerator as an insert, you must first prepare it: remove the compressor, remove the rubber seals and wash it thoroughly. However, a more durable option is to create a stationary chamber made of brick or concrete with subsequent thermal insulation.
- 🧱 Solid red brick or concrete rings to strengthen the walls.
- 🛢️ Bitumen mastic or roofing felt for high-quality waterproofing.
- 🏗️ Reinforcing mesh and cement brand M400 for pouring the floor and ceiling.
- 🌡️ Expanded polystyrene or expanded clay to create a thermal insulating layer.
- 🔨 Shovels, buckets, level, tape measure and tamper.
Selection of materials depends on the budget and the desired service life of the object. Using plastic barrels a volume of 200 liters is a popular budget option, but they are less durable than a permanent structure.
Earth work and pit preparation
The dimensions of the pit should exceed the dimensions of the future storage chamber by 40-50 cm on each side. This gap is necessary for laying waterproofing, insulation and arranging a drainage cushion. The depth of the pit is usually 2-2.5 meters, which allows you to achieve a zone of stable temperature.
The bottom of the pit must be carefully leveled and compacted. Then a layer of sand 10-15 cm thick is poured, which is spilled with water to compact it. A layer of crushed stone is laid on top to serve as drainage. This will prevent flooding of the storage facility during spring floods.
If the soil in the area is weak or sandy, it is recommended to strengthen the walls of the pit immediately after digging with temporary shields to prevent crumbling during work. In loose soils, you will have to dig carefully, perhaps using formwork as you go deeper.
☑️ Preparing the pit
It is important to provide a convenient descent into the pit for further work, so one of the walls of the pit is often made flat or a ladder is provided.
Waterproofing and construction of the chamber
Waterproofing is the most important stage on which dryness inside depends. The walls and bottom of the prepared pit (or the outer surface of the installed container) must be reliably protected from moisture. For this, bitumen mastic is used, applied in two layers, or pasting with roofing felt.
When building a brick chamber, a concrete floor pad with reinforcement is first poured. After it dries, the walls are laid out half a brick or brick thick. The seams between the bricks must be completely filled with mortar to prevent drafts and penetration of dampness.
| Wall material | Pros | Cons | Service life |
|---|---|---|---|
| Red brick | Durability, environmental friendliness | Labor intensity of installation | 50+ years |
| Concrete rings | Installation speed, strength | Requires special equipment for installation | 40-50 years |
| Plastic container | Tightness, lightness | Can float in groundwater | 20-30 years |
| Old refrigerator | Ready shelves, cheap | Metal corrosion, small volume | 5-10 years |
If used a metal body (for example refrigerator or a barrel), its outer surface is also treated with an anti-corrosion compound. Metal in the ground rusts quickly, so you cannot skimp on protection.
How to check the quality of waterproofing?
After applying the waterproofing layer and before filling the sinuses, you can conduct a visual inspection. There should be no tears, swelling or uncoated areas on the surface. For roofing felt, it is important that the overlap of the sheets is at least 10-15 cm, and the seams are thoroughly heated with a burner or coated with mastic.
Ventilation and temperature conditions
Without proper ventilation, mold will quickly appear in a confined space, and food will begin to rot due to lack of air exchange. For an earthen refrigerator, two pipes are enough: supply and exhaust, located in opposite corners.
The supply pipe goes down almost to the floor (to a height of 20-30 cm from the floor) to supply fresh cold air down. The exhaust pipe is installed near the ceiling to remove warm, moist air that rises. The diameter of the pipes is usually 50-100 mm.
The upper ends of the pipes must be covered with rodent nets and rain canopies. In winter, if severe frosts strike, the lower part of the exhaust pipe can be insulated, and the inflow can be temporarily blocked with a damper so as not to overcrowd the storage.
⚠️ Attention: Do not make the ventilation pipes too wide. Excessive air exchange will lead to food freezing in winter and heating in summer. The optimal diameter provides natural draft without drafts.
Draft adjustment is carried out using dampers or plugs installed at the ends of pipes indoors.
Insulation of the cover and entrance group
The hatch cover is the main heat loss bridge. It must be sealed, fit tightly to the body and have a layer of insulation. A double structure is often used: internal (light) and external (warm).
The internal cover can be made of boards or plywood, laying foam or mineral wool between the sheets. The outer cover should be more massive and moisture-resistant, for example, made of metal or thick larch treated with an antiseptic.
A rubber seal must be attached around the perimeter of the hatch, as in modern doors refrigerators. This will prevent melt water and cold air from entering in winter. It is advisable to build a small canopy or house over the hatch so that precipitation does not flow inside.
If the entrance to the cellar is at ground level, it is made around it a blind area with a slope from the hatch so that water flows to the sides.
Operation and care of the storage
Before storing the crop, the storage must be disinfected. The walls are treated with a solution of copper sulfate or slaked lime, and then ventilated well. This will kill fungal spores and bacteria.
During the storage season, you should regularly check the condition of the products and control the humidity. If condensation appears on the walls, it means that the ventilation is not working effectively enough or additional insulation is required.
- 🧹 Regularly remove the remains of rotten vegetables so that they do not infect neighboring stocks.
- 🌬️ Ventilate the cellar in dry weather by opening the hatch a few hours.
- 🕸️ Check ventilation pipes for cobwebs and blockages.
Proper care will extend the life of the structure and preserve the taste of your supplies until the next harvest.
Is it possible to use an old refrigerator entirely by simply burying it?
Theoretically it is possible, but it is not recommended. The metal body will quickly rust, and the foam insulation inside the walls can absorb moisture and lose its properties. In addition, the rubber seals will rot. It is better to use the body only as formwork or a mold, having first removed all the internal mechanisms and insulated the outside with bitumen and foam plastic.
What is the optimal depth for an earthen refrigerator?
The optimal depth of the storage floor is 2.5–3 meters from the surface of the earth. At this depth, the soil temperature remains stable all year round (+4...+8°C), which is ideal for storage. If you make it smaller, the products will spoil in summer, and in winter they may freeze.
What to do if there are rodents in the cellar?
It is necessary to install metal mesh on all ventilation holes (cells no more than 5 mm). You can place poisoned baits inside (with care not to poison the food) or use ultrasonic repellers. Treating the walls with lime with the addition of copper sulfate also helps.