How to dry the cellar: get rid of condensation, dampness, humidity, fungi and mold

High humidity in the cellar appears for various reasons. First of all, it is necessary to find out why it has increased, take measures to eliminate it, and then bring it back to normal. At the last stage, if necessary, disinfect. In any case, without properly organized ventilation and waterproofing, the problem will appear again and again. Therefore, before drying the cellar, check if the ventilation pipes are clogged, if the waterproofing is damaged.

Prevent dampness

As usual, this “disease” is easier (and cheaper) to prevent than to treat. It is still being decided at the design stage:

• The material of the walls and floor must have a low degree of hygroscopicity, it is bad to conduct water in both liquid and gaseous states. The best from this point of view is high-quality concrete – from M400 and above. But he builds a lot. You can add special substances to the usual M200 or M250 that increase the water-repellent properties. (read about concrete grades and their composition here)
  

• If groundwater is nearby or in spring/autumn its level rises significantly, external waterproofing is necessary. Liquid compositions are applied to the walls from the outside (better) or rolled ones are fused (cheaper, but less effective).
• If the cellar is built on a slope, above it it is necessary to lay a drainage pipe in the ground, which will drain the precipitation flowing down the slope.
• A blind area is made around the cellar (or the building under which it is located), which diverts precipitation flowing from the roof.
• Inside the cellar in opposite corners there should be two ventilation pipes with a diameter of at least 125 mm. One of them ends at floor level – 10 cm higher. Air from the street or premises (supply pipe) enters through it. The second ends almost under the ceiling, 10 cm below its level. This is an extractor. Ventilation pipes on the street should be covered with umbrellas so that foliage and precipitation do not get into them. The exhaust pipe (the one that ends near the ceiling) should be higher and it is better to install a deflector on it – to activate the draft. It can be painted black: due to the heating from the sun, traction should be better. Another subtlety: in order for the draft to be good, the ventilation ducts with natural air movement must be straight. If it is necessary to make a branch to the side, its angle of inclination must be at least 60 ° relative to the horizon, the length of the inclined section should not exceed 100 cm.
  

• Between the room located above and the basement there must be a vapor barrier that prevents the penetration of moisture both from the basement and into the basement.

Inspecting the floor

Very often in the cellar the floor is made of earth. Often it is the source of excess moisture. Through it, the moisture contained in the soil gets inside. To reduce the humidity in the cellar, you need to level the earthen floor, tamp it down and cover it with a thick plastic wrap. You can use roofing felt, but it breaks more often. Although it seems more durable, it breaks due to less elasticity.

It is not necessary to pour sand or earth on top of the film. Sometimes there is a large amount of water in the basement (accidental flooding). Then you simply take out the film, the water goes partly into the ground, partly evaporates through ventilation. After the dampness is gone, you can lay the floor again. If there is earth or sand on top, you will need to poke around in this liquid, extracting a film.

If, after laying the film, the level of humidity in the cellar has decreased, then you have found the cause. You can leave everything as it is, only periodically change the “flooring”, or you can make a concrete floor with full waterproofing. The choice is yours. To prevent the film from tearing when walked on, knock down the wooden shields and throw them on the floor.

Improving waterproofing

The second reason why humidity rises in the basement is an insufficient degree of vapor barrier or waterproofing of the walls. This usually occurs if the cellar is lined with bricks, especially silicate. The material is very hygroscopic and passes water vapor well. They settle in drops on the ceiling and all objects.

The problem can be solved if you make a good external waterproofing: dig out the walls and apply bituminous mastic in two layers. Previously coated with resin, but mastic is more effective and easier to handle.

But excavation is far from always a joy, and it is not always possible to dig out the walls. In this case, you can make an internal waterproofing of the walls of the cellar. For this, there are cement-based impregnations: Pnetron, Kalmatron, Hydrotex, etc. They penetrate to a depth of up to half a meter into the thickness of the material (concrete, brick, etc.) and block the capillaries through which water seeps through. Water permeability is greatly reduced. Their only downside is the price. But they are really effective.

All these measures will prevent the appearance of high humidity in the basement. But what to do if there is already moisture, how to dry the cellar? Next, consider ways to reduce humidity.

How to organize drip irrigation of the garden yourself, read here. 

Preparatory work

All supplies are taken out of the basement, as well as all wooden structures, they are well cleaned. On the street, they inspect wood – shelves / boxes / boxes. If they are not affected, and there is no fungus or mold, they are simply laid out in the sun to dry. If there are signs of damage, the wood is impregnated with a solution of copper sulfate (concentration 5-10%, no more).

Whitewashing with lime gives good results, it will also “collect” moisture from the air. Therefore, before draining the basement, it makes sense to whitewash everything. They just don’t do it the way they do it. It is necessary to apply a thick layer of lime on the walls. To do this, make a bucket of thick whitewash, add a little diluted copper sulphate. It is an excellent disinfectant, but the concentration should not be higher than 5%, maximum – 10. The resulting thick liquid is poured in half into two containers.

The first half is lowered into the basement, dressed in old clothes, put on glasses, and cover their hands. They take a paint brush for whitewashing (it looks more like a small broom) and smear the corners well with it. Then you slurp the liquid with a brush, and spray it on the walls and ceiling. Just dip in thick whitewash and spray on the walls. They are covered with drops, tubercles of lime. 

After everything is covered with lime, wait a day until it dries. Repeat everything with the second bucket. As a result, the walls and ceiling are porous and uneven. But condensation rarely hangs on them: lime retains moisture well inside. After the lime dries, you can begin to dry the cellar.

Building a greenhouse with your own hands is described here.

Basement dehumidification with ventilation

Sometimes it happens like this: it was dry in the cellar, and suddenly dampness appeared. One reason is poor ventilation. First of all, check the cleanliness of the ventilation ducts. If necessary, clean. If everything is fine, but the dampness does not go away, then the exhaust pipe is not working well. This happens when the air in the cellar is colder than outside. Heavy and cold, he himself will not climb the pipe. A paradoxical, at first glance, situation arises: it was cold and damp outside – it was dry in the cellar. It got warmer – drops of moisture hung on the ceiling, walls and objects, a musty smell appeared. In this case, in order to dry the cellar, it is necessary to activate the movement of air. There are several solutions.

1.  Put a powerful fan on the exhaust pipe that will draw air. Ensure the flow of air masses – open the hatch, if any – windows or dampers. In a few days (from three to ten) everything will dry out.
   

2. Use the old “old-fashioned method” with a candle. It is suitable if there is no electricity and there is nowhere to turn on the fan. This happens if the cellar is built separately, on the street. To dry it, temporarily grow it into the exhaust pipe (the one that ends under the ceiling) so that it almost touches the floor (it was 5-10 cm higher). A burning candle is slipped under it, but it is placed on some kind of non-combustible foundation. Due to the fact that the air in the pipe is heated, a normal draft arises, the damp air is drawn from the floor. Change the candle until the basement dries out. Instead of candles, you can use dry alcohol tablets. Sometimes the flame of a candle is not enough to start the movement of air. Then you first slip a piece of a burning newspaper into the pipe (just be careful, do not set fire to or melt the ventilation), after it has burned out, move a burning candle.

Sometimes increased air movement leads to the fact that the humidity in the cellar does not decrease, but increases. This can often be seen in hot weather. The reason is this. Warm air carries with it a significant amount of moisture in the form of vapours. Getting into a cool cellar, the air cools down, and moisture condenses on the coldest surfaces: the ceiling, walls, sometimes on shelves and cans. If you have just such a case, then stop ventilation. Even close the supply pipe and close the lid well, limiting the flow of warm air.

How to dry the cellar in this case? Wait until autumn, and when there is no rain yet, but the temperature is already about + 10 ° C, start ventilation using one of the methods proposed above. Works. If your nights are cold in summer, you can turn on the fan at night and close the ventilation ducts during the day. So gradually you can reduce the humidity in the cellar in the summer.

We heat the cellar

If you need to remove dampness even during warm weather, and ventilation only worsens the situation, you need to heat the air in the basement so that it comes out on its own, taking moisture away (the higher the air temperature, the more vapor it can contain).

To do this, take an old bucket or other metal container of about the same volume. They make a lot of holes in it (you can use an ax) in the bottom and walls. Such a leaky bucket is tied to a cable (attach securely). Coals for barbecue are poured inside (you can burn it yourself), the bucket should be almost full. Coals are kindled and stable combustion is achieved (to accelerate combustion, you can adapt a vacuum cleaner by turning it on for blowing). A bucket of glowing coals is lowered on a cable into the cellar, fixed so that it hangs above the bottom, and the lid is closed.

Periodically, the cellar lid must be opened, letting in an additional portion of oxygen (every 20-30 minutes). You can put a fan on the supply pipe or periodically turn on the same vacuum cleaner. If the coals still go out, they are kindled again.

Attention! It is better not to climb inside, do everything from above. Firstly, the temperature there is high (in a room of about 2 * 3 meters, about 70 ° C), and secondly, smoke and, perhaps, carbon monoxide accumulate inside.

As the coals burned out, they took out the bucket, closed the lid. Do not look inside for three days: smoke and gases will kill the mold and, along with drying, you will disinfect your cellar. Usually one such “firebox” is enough to dry the basement in the house or on the street. Similarly, you can get rid of dampness in the basement under the garage.

Sometimes coke or coal is used instead of charcoal. It gives a higher temperature and “processing” takes longer, but it burns more difficult, requires more oxygen, often forced blowing (adapt an old vacuum cleaner and a corrugated hose, but turn it on for blowing). But the temperature rises even higher and dries even more efficiently. But the price of coke is high, even if you don’t go broke because of buying a bucket.

Instead of a bucket of burning coal, you can use other heaters:

• a propane burner (lower the burning one on the wire, make sure that it does not light anything and leave it hanging in the middle, as tired, close the valve, open the lid only every other day);
• decent power heat gun (3-5 kW);
• kirogaz;
• lower the potbelly stove into the basement and heat it.

All these methods can be used, but you have to go down into the cellar in order to ignite the kyrogaz or potbelly stove. And this is an unsafe undertaking and do not use this method alone. It is necessary that someone belay you upstairs. Regarding the heat gun: it is also better to lower it by tying it (tying it) with a cable, and not lowering it yourself.

How to dry the basement in the garage is described in the video.

How to make high beds (to increase productivity) read here.

How to dry a cellar without ventilation

If ventilation was not done during construction, it is advisable to arrange it now. At least some: it will be easier to get rid of dampness. Better, of course, two pipes – one for inflow, the second for outflow – as described at the beginning of the article. If the cellar is made separately on the street, it is easier to organize: they broke through the ground and the roof of the cellar, inserted pipes, filled everything with concrete.

It’s more difficult with a garage, but no one here clings to aesthetics. But if the basement is without ventilation under the house, it’s more difficult to make it: it’s better not to break the foundation, and you can’t stretch many pipes through the floor into the room. But even in this case, make at least one pipe. Even if through the cover, lead to the wall or ceiling, put the supply and exhaust fan. It can be switched on either for supply or exhaust, and in this way to somehow dry the cellar.

With at least such ventilation, you can use any of the methods described above. You can also try to collect more moisture. For this inside lay out hygroscopic materials:

• Pour dry sawdust, when it gets wet – throw it away, fill in new ones. Drying this basement will not dry it out, but it will lower the humidity. There will be no drops of condensate on the ceiling for sure.
• Slaked lime. It is laid out around the perimeter, along the walls and on the shelves. It not only collects moisture, but also kills fungi in pairs.
  

• Calcium chloride. 1 kg of dry matter absorbs 1,5 liters of water. You buy some tens of kg, lay it out, collect it in a day, warm it up (calcine it) and you can use it again. But you also need to work carefully: chlorine and calcium vapors are also toxic.
• Dry cardboard boxes. No matter how funny, they also absorb moisture well. Lay a few pieces of dry ones, after 12-20 hours they are so wet that they almost spread in your hands. Throw it away, throw in new ones. Cheap and cheerful. Drying the cellar will not dry it out at all, but it will collect condensate from the ceiling and walls.

If all these dances with tambourines do not inspire confidence in you (although they work), you can dry the cellar using modern technology. There are household appliances household dehumidifiers. They are often placed in pools to get rid of dampness in the room. You will need a medium power model. They cost about 20-30 thousand rubles, they work from a 220 V household network. In the process, they collect moisture from the air into a special container. You will need to periodically drain the water.

However, keep in mind that the use of dehumidifiers in the cellar is possible only if there are no vegetables laid down for the winter. During operation, the appliance generates heat, which will adversely affect the storage of products.

Disinfection and fight against fungi and mold

The increased humidity in the cellar leads to the fact that mold, fungi of various types and colors appear on the walls, ceiling shelves, and all this beauty is accompanied by “aromas”. In this case, everything that can be taken out of the cellar is taken out and laid out to dry. After drying, whitewash wooden shelves, boxes, boards, racks with lime with the addition of a solution of copper sulfate. Better twice.

In the cellar, you clean off all the growths from the walls and ceiling, whiten with lime and blue vitriol twice (the technology is described at the beginning of the article). Before the main drying, special events can be carried out that will destroy the spores (or neutralize them for a while).

Vapors of lime

In the cellar, put a barrel filled with quicklime. Lime is taken at the rate of 3 kg per 1 cubic meter of volume. In a barrel of lime should be a maximum, a little more than half. Fill everything with water. Don’t interfere. Get out quickly and tightly (hermetically) close the lid and all ventilation ducts. You can open in two days, ventilate well, then you can go down.

Repeat the treatment after 7-10 days. Vapors of lime should burn out mold and fungi, destroy insects and their larvae. They also cope with the smells of dampness and mustiness very effectively. True, for several days in the cellar it will smell like lime.

Sulfuric (smoke) bomb

Use sulfur flask. They are sold in stores selling seeds or household equipment. Each has instructions. But, in short, you need to act according to the following scheme:

• take out all metal things, if this is not possible, cover them with a layer of lubricant – grease or something similar.
• You set fire to the wick of the sulfur checker, it begins to smolder.
• Get out quickly, close the lid and ventilation ducts hermetically, leave for 5-6 hours.

If the basement is in the house, it is advisable to leave it for the time of processing: a couple of breaths with insufficient tightness and the lungs will need to be put in order for a long time.

Disinfection occurs due to the formation of sulfuric acid. It is obtained by the reaction of sulfuric anhydride and water. Therefore, the mold is more effectively killed with a sulfur checker in wet cellars.

After 5-6 hours (or after the time indicated on the package), open the ventilation ducts and the lid (in that order). Leave open for at least 12 hours. The remaining gases are vented during this time. You can come in.

From the experience of operating such checkers, we can say that they need to be ignited twice as much as the norm. Then everything will really be neutralized.

Mold remover

Sometimes white fluffy growth appears on wood or walls. This is one type of fungus. It can be dealt with by the methods described above, but if only it is present, you can find a means for removing hard mounting foam on the construction market (they sell it in the same place as foam). Insert the tube into the mounting gun and apply to places with fungus. It immediately starts to roll over. And then on this place does not appear.

Sprinkling on the floor

If your floor is earthen, lay a thick plastic film on it (for which it is described above), knock down the wooden bars and throw them on the floor. Scatter pieces of slaked lime under them. And they will collect moisture and create “bad” conditions for fungi.

How to dry out a basement after a flood

If the flooding was accidental, you need to pump out water in any way possible, and then proceed according to the standard scheme:

• Take out everything you can from their cellar.
• Leave all the lid and vents open for a while.
• When more or less dry, remove debris, fungi, mold from the walls and floor.
• Whitewash with lime.
• Dry one of the ways.

If the flooding is periodic – in the spring, for example, you will have to make a full-fledged drainage system, and this is a separate conversation.

All the methods described above on how to dry the cellar are mostly based on practical experience. They are used everywhere and very often. In one case, one method works, in the other, another. Your task is to find the most effective for your situation.