The summer season often poses the task of preserving food freshness to the owners of suburban areas, especially when a power outage or its complete absence makes it impossible for a standard household appliance to operate refrigeration equipment. In such situations, the optimal solution is to create a stationary storage facility that takes advantage of the natural cold of the soil, which maintains a stable temperature all year round. This is not just a hole in the garden, but a complex engineering structure that requires precise calculations and compliance with construction technologies.
The idea of a buried one storage is not new: our ancestors have used similar structures for centuries to preserve crops and preparations, but modern materials can significantly improve their efficiency and durability. Properly designed cellar able to maintain temperatures from +2 to +5 degrees even in the summer heat, which is ideal for storing meat, dairy products and vegetables. The creation of such an object requires not only physical effort, but also a deep understanding of the heat exchange processes and hydrogeology of the site.
Before starting excavation work, it is necessary to conduct a thorough analysis of the soil and groundwater level, since an error at the planning stage can lead to flooding of the structure or its rapid destruction. It is important to understand that temperature conditions in an earthen refrigerator directly depends on the depth of soil freezing in your region and the thermal conductivity of the insulating materials used. Below we will analyze in detail all the stages of creating a reliable and durable storage facility.
Selection of location and geological exploration of the site
The first and critically important stage is determining the optimal location for the future storage facility, since not only temperature stability, but also the durability of the entire structure depends on this. It is best to choose elevated areas in an area where the groundwater level is below the expected bottom of the cellar, which minimizes the risk of flooding in the spring. If your site is located in a lowland, you will have to lay a more complex drainage system or raise the structure above ground level, creating an artificial embankment.
It is necessary to take into account the wind rose and illumination: it is advisable to locate the entrance to the cellar on the north side, so that direct sunlight does not heat the structure in the summer. You should also avoid places where active snow melting or accumulation of melt water occurs in winter, since excess moisture is the main enemy of underground structures. Geological exploration can be carried out by test drilling a well to the depth of the planned pit.
There are several types of structures that can be implemented depending on the conditions of your site:
- 🏡 Surfaced cellar —is completely underground, provides better thermal insulation, but requires a low water level.
- 🏔️ Glacier cellar —partially or completely elevated above the ground, often covered with soil, ideal for areas with high waters.
- 🏠 Wall storage shed —attached to the main wall of a house or garage, which simplifies access, but requires high-quality insulation of the building's foundation.
If you plan to build refrigerator next to the house, be sure to consult with an architect or an experienced builder.
⚠️ Attention: Do not start digging a pit without making sure that there are no underground communications (gas pipeline, electric cable, water supply). Damage to gas pipes can lead to catastrophic consequences.
Design and calculation of pit dimensions
After choosing a location, you need to decide on the dimensions of the future storage facility, which will depend on your needs for storage volumes and available space. Standard family cellar usually has dimensions of 2x2 or 2x3 meters with a depth of about 2-2.5 meters, which allows you to comfortably fit inside and place shelving. A depth of less than 1.8 meters is impractical, since temperature fluctuations in the upper layers of the soil are too great for high-quality storage of products.
When designing, you should take into account the thickness of the walls and waterproofing: if you plan to do brickwork or concreting, the pit should be 30-40 cm wider than the internal space on each side sides. For wooden structures or the use of ready-made plastic caissons the gap may be smaller, but sufficient for laying insulation. The shape of the pit also matters: a rectangle is more convenient for placing shelves, but round or oval shapes resist soil pressure better.
The roof of the storage facility requires special attention, since it is through it that the main heat loss occurs. The ceiling must be insulated with a layer of expanded clay, sawdust or expanded polystyrene with a thickness of at least 20-30 cm. An entrance vestibule or a coffered chamber will help create an air cushion that will work as a thermal gateway when the door is opened.
It is better to calculate materials with a margin of 10-15%, since during the work unforeseen circumstances may arise that require additional strengthening walls or bottom. An accurate drawing indicating all dimensions and junction units will help to avoid mistakes when purchasing building materials.
Earthwork and foundation installation
Digging a pit is the most labor-intensive stage, which can be done manually with a shovel or mechanized using an excavator. When digging by hand, they try to make the walls of the pit vertical, but if the soil is loose, they will have to be sloped or immediately reinforced with shields to prevent crumbling. The excavated soil should not be transported far: it will be needed for backfilling and forming an embankment above the cellar.
The bottom of the pit requires careful preparation, as it will take the load from the walls and products. The first step is to remove the fertile layer of soil, after which a drainage cushion of crushed stone and sand is installed. On sandy soils, the bottom can simply be compacted, but on clay soils that do not allow water to pass through well, high-quality drainage is necessary.
The technology for creating a foundation is as follows:
- Levelling and compacting the bottom of the pit.
- Laying a layer of coarse crushed stone 10-15 thick see
- Filling a layer of sand 5-10 cm thick and pouring water for compaction.
- Laying waterproofing material (roofing felt or thick film).
- Pouring a concrete screed or laying wooden flooring.
☑️ Preparation of the base
If the groundwater level is high, at the bottom of the pit they equip a pit (sump) to collect water, from where it can be pumped out with a drainage pump. A concrete screed with the addition of liquid glass or special penetrating compounds will create a reliable barrier to moisture rising from below.
⚠️ Attention: When working in a deep pit (more than 1.5 meters), be sure to use safety belts and monitor the condition of the walls, especially after rain. Shedding of soil can be fatal.
Waterproofing and insulation of the structure
Quality waterproofing is the key to dryness and long service life of your underground refrigerator, since concrete and brick have a effect and can draw moisture from the soil. For the outside of walls, it is best to use bitumen mastics in combination with rolled materials such as roofing felt or modern membranes. Waterproofing should be applied in two layers with overlapping joints, paying special attention to the corners and places where communications enter.
Insulation of the structure is necessary to maintain a stable temperature: even deep soil will not save you from summer heat without additional protection. They often use expanded polystyreneas insulation, which is not afraid of moisture, or expanded clay, filling the space between the walls of the pit and the cellar structure. The thickness of the insulating layer should be at least 10 cm for walls and 20-30 cm for ceilings.
Comparison of popular waterproofing materials:
| Material | Durability | Difficulty of application | Cost |
|---|---|---|---|
| Bitumen mastic | 10-15 years | Low | Low |
| Roofing felt | 15-20 years | Average | Low |
| Penetrating insulation | 50+ years | High | High |
| Liquid rubber | 30+ years | Medium | Medium |
Interior wall decoration also plays the role of an additional barrier: plastering with cement mortar with the addition of antiseptics will protect the structure from mold. It is important to ensure the tightness of the input of ventilation pipes, using polyurethane foam or sealants that are resistant to temperature changes.
Installation of a ventilation system
Properly working ventilation is the “lungs” of your cellar, without which the products will quickly rot from excess humidity and lack of oxygen. The classic scheme involves installing two pipes: a supply pipe, which supplies fresh air from below, and an exhaust pipe, which removes warm and humid air from above. Natural air circulation occurs due to the difference in temperature and density of air masses inside and outside the storage.
The supply pipe is usually located at a height of 20-30 cm from the floor, lowering it almost to the very bottom so that cold air washes the products. The exhaust pipe is mounted under the ceiling, where warm air accumulates, and is discharged to the roof of the cellar or through the wall to a height of at least 1.5 meters above ground level. The diameter of the pipes is calculated based on the volume of the room: for a standard cellar of 2x2 meters, pipes with a diameter of 100-110 mm are sufficient.
How to check the draft in the ventilation?
Bring a lit candle or a strip of thin paper to the opening of the exhaust pipe. If the flame or paper is deflected towards the pipe, there is a draft. If smoke goes inside, there is no ventilation, you need to clean the channel or extend the pipe.
The pipes must be protected from precipitation and rodents: deflectors or caps are installed on the upper sections, and a mesh can be inserted inside. In winter, when the outside temperature drops below -10 degrees, it is recommended to partially block the ventilation holes with dampers so as not to freeze the food.
The efficiency of the system can be checked using a sheet of paper or smoke: if the air flow is felt, it means circulation it is adjusted correctly. Regular cleaning of pipes from cobwebs and debris will help maintain a normal microclimate.
Internal arrangement and operation
The final stage of creating a refrigerator in the ground involves the installation of shelving, drawers and lighting. It is better to make shelves removable and from materials that are easy to clean and do not absorb odors, for example, from treated wood or metal with an anti-corrosion coating. The distance between the shelves should be such that you can freely remove jars and boxes without touching adjacent rows.
Lighting in the cellar should be safe: use low voltage lamps (12V) or LED lamps with a moisture-proof housing. Lay the electrical wiring in corrugated pipes, and place the switch outside or at the entrance so as not to look for it in the dark with wet hands.
To maintain an optimal microclimate, it is recommended:
- 🌡️ Regularly ventilate the room in dry weather by opening doors or hatches.
- 🧼 Carry out annual disinfection of walls and shelves with a solution of copper sulfate or lime.
- ❄️ Place containers with quicklime or salt to absorb excess moisture.
Before the first loading of products, the cellar must be thoroughly dried and warmed up if it was built in the cold season. Loading of vegetables and fruits is carried out after their preliminary sorting: damaged fruits can start the process of rotting throughout the storage.
⚠️ Attention: Never store vegetables and fruits that emit ethylene (apples, pears) and root vegetables (potatoes, carrots) in the same compartment, since ethylene accelerates the germination of the latter.
Frequently asked questions (FAQ)
Is it possible to make a refrigerator in the ground if the groundwater is high?
Yes, this is possible, but it will require more complex engineering solutions. Instead of a buried cellar, a ground or semi-buried storage shed is built with mandatory external waterproofing and a ring drainage system around the foundation. Another effective solution is to use ready-made plastic or metal caissons, which are sealed and resistant to water pressure.
What is the optimal temperature in an earthen refrigerator?
For long-term storage of most vegetables, fruits, meat and dairy products, the optimal temperature is considered to be in the range from +2 to +5 degrees Celsius. At temperatures below 0 degrees, many vegetables can freeze and lose their taste, and above +7 degrees, active growth of bacteria begins.
What is the best way to insulate the cellar lid?
The hatch lid must be sealed and insulated. It is best to use a sandwich structure: a wooden frame, inside of which there is foam or extruded polystyrene foam with a thickness of at least 50 mm. The top of the lid is sheathed with moisture-resistant plywood or metal, and sealing rubber is glued around the perimeter.
How to deal with mold in the cellar?
Mold appears due to excess humidity and poor ventilation. To combat it, it is necessary to establish air exchange, dry the room, clean the affected areas with a brush and treat the walls with a solution of copper sulfate or slaked lime with the addition of formaldehyde. Burning a sulfur bomb gives a good effect, but after this the cellar must be thoroughly ventilated.