A bathhouse on a personal plot or a summer residence is the dream of many owners. Such water procedures are not only pleasant, but also useful - they cleanse and temper the body, improve blood circulation. Friendly communication over a cup of fragrant tea after the steam room can hardly be overestimated. When it comes to choosing a material for building a bath, it is not only the price factor that needs to be taken into account. This is a specific room with special functions, high humidity and temperature. Therefore, it is important not to get lost among the diversity that the market offers. To choose what to build a bath from, it is recommended to consider in advance various building materials from the point of view of their suitability for the construction of this building. This will allow you to understand which one will be optimal for your needs and conditions.

General requirements for materials from which baths are built in the country

The construction of baths, like any other facilities, is regulated by SNiP norms:

• SNiP 30-02-97, which describes the rules for building garden and backyard plots;
• SP 11-106-97 - rules for creating a site development project.

Many owners are surprised to learn that the requirements for baths are, in some respects, even more stringent than for residential buildings. This is primarily due to the increased fire hazard due to the presence of a furnace. In addition, there are technical requirements for building materials. They must:

• provide good thermal insulation;
• be resistant to high humidity and temperature.

The question of price in this case is in last place, although it also matters, all other things being equal.

What to build a bath from: the advantages and disadvantages of different materials

The market offers us many options:

• wood;
• aerated concrete;
• expanded clay concrete;
• brick;
• arbolite;
• cinder block.

Gas block or foam block

Aerated concrete blocks are made from cement, quartz sand and foaming agents. The material belongs to aerated concrete. The resulting blocks are processed in autoclaves to increase their strength. They have the correct geometric shape and are, in fact, a synthetic stone.

Advantages of aerated concrete:

1. Fire resistance. This is an important indicator of the material from which the bath will be built.
2. High strength that increases over time.
3. Low weight. Thanks to this, you can save on the foundation.
4. Ease of processing. It is easy to cut with a hacksaw and drill with a drill.

The main disadvantages of this material are its high cost and hygroscopicity (the ability to absorb and accumulate moisture). Therefore, the use of aerated concrete for the construction of a bath requires some measures. To reduce the amount of absorbed moisture, special additives are introduced into the composition of the material.

Additionally, during construction, it will be necessary to create steam and waterproofing.

For a bath, such a material characteristic as its thermal conductivity is important. In aerated concrete, it depends on its density. The material of different grades from D300 to D600 has a thermal conductivity coefficient ranging from 0.072 to 0.141. The lower the density of the gas blocks, the less they conduct heat. At a low density, the cells of the material contain a lot of air, which heats up slowly and is an obstacle to heat transfer. It turns out the effect of a thermos. It should be borne in mind that the thermal conductivity index is given for aerated concrete at zero humidity. When moisture is absorbed, it rises markedly.

Another feature of the construction of gas blocks is that they need to be laid on a special glue, which looks like a cement mortar. The latter is not recommended to be used, since the blocks absorb moisture from it, due to which the thermal insulation of the room is reduced.

Frame bath

Frame baths are gaining more and more popularity due to their advantages:

1. Light weight, thanks to which it can be mounted on a lightweight foundation.
2. High construction speed. On average, a frame bath can be assembled 3 times faster than a timber or brick bath. Erection takes no more than 2-3 weeks.
3. Good thermal insulation. In terms of warmth, it is comparable to log and squared buildings.
4. It can be erected at any time of the year, including in winter at temperatures down to -15 degrees.
5. The material of the walls absorbs and allows air to pass through, ensuring their "breathing", therefore, such a bath has a pleasant microclimate.
6. The natural materials of the frame are safe for human health.

Such a bath is not devoid of some disadvantages:

1. Shrinkage within 2 years, at which the building can settle by 10 cm. To reduce it, it is necessary to use kiln-dried materials.
2. Additional costs for insulation and finishing. The frame itself is cheaper than timber or brick baths, but the costs increase due to internal and external finishing.
3. Difficulty choosing an effective insulation. Mineral wool or foam will not work here. We'll have to look for insulation that does not absorb moisture and does not ignite.

A frame bath is considered the best budget option.

Brick

Brick as a material for building a bath has three main advantages:

1. Durability. Brick baths can serve more than a hundred years, while the average service life of wooden ones is 15–20 years.
2. Attractive appearance. The brick does not need additional finishing. Any design elements of buildings can be created from it.
3. Fire resistance. Unlike wood, brick does not burn.

The disadvantages of this material in the context of building a bath can be counted much more:

1. The need to create a strip foundation. This is an expensive and time consuming process.
2. The brick takes longer to warm up. It takes no more than 1–1.5 hours to kindle a wooden bath. To warm up a brick, you will need much more time and, accordingly, fuel.
3. Poor ventilation. Brick walls "breathe" much worse than wooden or frame ones.
4. High price.
5. Long construction period. You need to wait until the concrete in the foundation dries up and gains strength. Masonry also takes a lot of time and effort.

Due to the long service life and fire safety, many owners prefer brick. A beautiful appearance is an additional incentive. If you also decide to build a bath from it, use some tips:

1. The best option for price and quality is one and a half red brick. And they also often use gas silicate.
2. In such a bath, you need to think over the ventilation system, leave ventilation gaps.
3. The cement for the mortar must be taken not lower than the M200 brand. It will ensure the reliability of the seams and good thermal insulation.
4. It is better to insulate a brick bath from the inside, so as not to spoil the external appearance.

Expanded clay concrete

It is a naturally cured monolithic material that contains cement and expanded clay - foamed and fired clay. Expanded clay concrete has a number of advantages - it is non-toxic, absorbs moisture poorly and has low thermal conductivity. In addition, such blocks are lightweight. This facilitates construction and reduces the cost of the foundation. A bath made of this material requires less insulation than, for example, aerated concrete or a heating block. Frost resistance, which means durability, of expanded clay concrete is 5 times higher than that of aerated concrete blocks, and 2 times higher than that of foam blocks. Another indisputable advantage of the material is zero shrinkage.

Thermal conductivity depends on the filler fraction, therefore it ranges from 0.15 to 0.45. The larger the fraction, the lower it is, but also the lower the density of the material.

For masonry walls made of expanded clay concrete blocks, you can use ordinary cement-sand mortar or special adhesive mixtures.

Cinder block

This is a cheap building material, which is obtained by pouring concrete into waste - products of combustion of coal and other materials or sawdust. In the second case, the material is called sawdust concrete (it is absolutely non-flammable).

Cinder blocks come with voids inside and full-bodied.

Material advantages:

• long service life - up to 50 years;
• fire resistance;
• low cost compared to wood or brick;
• a variety of fillers allows you to choose the material for different needs.

Among the disadvantages, the main ones are:

• hygroscopicity - when using material for the construction of a bath, its waterproofing will be required;
• increased thermal conductivity - the bath will have to be additionally insulated.

Cinder blocks have another important feature. Before being used in construction, they must be weathered in the open air for a year. Otherwise, the blocks will emit harmful substances. Therefore, the only obvious advantage of this material is its low price. For the construction of a bath, this is not the best option.

Wood

A wood bath is a classic option. There are different types of wood, and lumber from it also differs in characteristics. Industrial are:

1. Pine. This tree has a natural defense against mold and pests - their resin. Wood has a high moisture resistance. Pine is available - there is a lot of it on the market, it has a low cost compared to other species. Its disadvantage as a material for building a bath is the property of "crying" at high temperatures. Needs additional treatment against decay.
2. Linden. This type of wood is easy to work with. Suitable for the construction of a bath, since it has an important property - good heat resistance. However, linden darkens without additional processing. She is also afraid of moisture.
3. Aspen. It is not afraid of moisture, has a high density, and becomes even denser over the years. Aspen gives low shrinkage. It is durable, practically does not crack when dry. In addition, the wood has a beautiful reddish color. The disadvantages of aspen are the high price and the complexity of processing due to the high density. And it is also believed that aspen is not suitable for building baths, because because of it, the state of health worsens and the head begins to hurt.
4. Fir. It is rarely used in construction for two reasons - it is prone to decay and has soft and fragile wood.
5. Alder. It is common in Russian forests, but it still has a rather high cost. The wood has a beautiful color - from fiery to brick. Low shrinkage. Practically does not warp. It is easy to process, does not twist, which is important for the construction of a bath. However, it darkens after several years of service and is subject to decay.

Log house

Rounded logs are considered a completely ecological product, unlike glued beams. A bathhouse built from it will not need additional external and internal finishing, since the log has a natural chic appearance. Due to the minimum gaps on the crowns, log houses made of rounded logs are distinguished by increased thermal insulation. The ability to connect logs at any angle allows you to implement unique design solutions in the construction of buildings. The disadvantages of a log are twisting, cracking, bending. The material exhibits high shrinkage.

Beams

Profiled timber can be solid and glued. In general, it is not subject to deformation, like a log, and has good performance. It is impregnated with antiseptics and fire retardants to increase resistance to biological factors and fire. One-piece profiled timber is considered more environmentally friendly, since it does not contain adhesives. At the same time, glued is less susceptible to cracking and has increased strength, resistance to deformation.

Building a wooden bathhouse with your own hands requires certain skills. If you do not have sufficient experience, it is better to hire specialists for this.

Arbolite blocks

This material has been known since the times of the USSR. Blocks are 90% wood waste. They are brought to the required size in a chipper and crusher, then poured with cement with the addition of calcium chloride or liquid sodium glass. These additives are needed in order to neutralize resin acids that destroy wood and to accelerate the hardening of the mass.

Arbolit as a building material has a number of advantages:

• low thermal conductivity;
• the ability to maintain a comfortable level of humidity in the room;
• environmental friendliness;
• low cost.

Subject to the purchase of high-quality blocks, this material can be called a good option for a bath. Another important feature of wood concrete is its heat capacity, which is higher than that of air. This means that in a bathhouse built from it, the air will first warm up, and then the walls. In the case of using bricks, the opposite is true.

Arbolite is suitable only for low-rise construction, since it has low strength and is not able to withstand heavy loads. It is worth considering its high hygroscopicity. Waterproofing and a good ventilation system are indispensable here. For finishing, you will not be able to use ordinary plaster.

Outside, wood concrete walls are best finished with facing bricks, clapboard or moisture-resistant wood. For a bath, lining will be the best option, otherwise the cost of construction will increase, which will make the use of this material disappear.

What material to choose to build a bath (reviews)

Nothing helps to make a choice like the reviews of people who have experienced something for themselves.

Before building my own bath, I thought that it must be made of wood, but wood breathes. But no matter how I walked around such baths, no matter how much I was inside, I did not see (feel) this breath. Today I am sure that the bath is the conditions that must be created in the steam room, the optimal ratio of humidity and temperature. The project was born quickly, because I clearly understood what I wanted from it: a steam room and a washing room must be separate, a large and comfortable rest room, a firebox with the effect of a fireplace and ... the possibility of spending time comfortably in winter. Bath in winter is a song. Therefore, I chose a foam block for the walls.

Konstantin

https://www.forumhouse.ru/threads/394720/

I have a steam room / sink - this is a log house made of aspen d = 250 \ 300 and the anteroom is a frame annex. Under the pouring floors, I did not pour concrete, but welded a frame of 12 reinforcement bars with slopes in the center to the scupper (aka ladder) and pulled on a thick plastic wrap. I also made "eternal" logs under the floors, since we sell a used thick-walled pipe (76 \ 6 mm) inexpensively, welded to it platforms from a strip along the edges (so as not to spin) and scattered 6 pieces. with an interval of 0.5 m (the ends of the pipes lay on the lower strapping bar, in places where half-logs are placed near the log house). Another "know-how" so that the boards of pouring floors are not attached to the logs (you can always lift them to dry, or clean the drain under them) and so that they do not run down and lie at the same intervals. Along the edges of the boards (with an indent of 10 cm), I drilled and inserted PVC "mushrooms" to fix the insulation on the facades, then measure 10 mm and cut the mushroom with a hacksaw for metal. It turns out a board with remote chopiks along the edges, simple and reliable, will not rot and hold on tightly.

Andrey

https://www.forumhouse.ru/threads/282522/page-2

In fact, from the point of view of quality, the frame 100 or the timber 100, raw, unplaned, and the frame 200 are optimal technologies, respectively, for an unheated and heated bath.

Viant

https://www.forumhouse.ru/threads/389121/

Good day! Wood concrete material for a bath is not bad, but you need to use it wisely. Namely, it is possible to insulate, if the arbolite is not plastered, it breathes great, the cake will turn out like this: internal sheathing (solid wood) ventilation gap 1.5–2 cm, vapor barrier, basalt insulation 5–10 cm, wood concrete, windproof film, ventilation gap 2–5 cm, outer sheathing. Why is basalt insulation used? Because the thermal conductivity of the insulation is much lower than that of wood concrete, accordingly there is less loss and faster warming up. If plastering outside, then such a structure will not be able to breathe towards the street and will accumulate moisture, and it can even penetrate through the vapor barrier, since small leaks and damage are possible. In terms of vapor permeability, the materials should follow each other in the order of increasing vapor permeability (from the inside out), there are no plasters comparable in vapor permeability to wood concrete.

Tooth

https://www.forumhouse.ru/threads/100295/

Regarding the construction of a glued laminated timber bath. A definite plus, from my point of view, is the minimal shrinkage, and the clear behavior of the timber in the future. Of course, on condition of a well-made timber.

Konstantin

https://www.forumhouse.ru/threads/390466/

Video: how to choose material for building a steam room

There are many options for building materials for a bath, and each of them is good in its own way. Making the right choice requires a careful study of the pros and cons of each. If you know what is your priority - price, appearance, simplicity and speed of construction or thermal insulation properties, then you can easily determine the right material for yourself.

The material for the walls of the bath determines the quality, functionality and durability of the future structure. The most environmentally friendly is wood.

The timber walls erected for the bath give the structure a solid look, it is easy to breathe in it, and the steam becomes more saturated. Now foam and cinder blocks are becoming more popular for the walls of the bath. What material to choose for construction, what should be the thickness of the walls for a bath, the article will tell you.

What material can be used to build a bath

What are the walls for the bath made of, for its long-term use and an attractive look?

The best materials for this are:

• Logs.
• Beams(see Do-it-yourself timber baths: how interior decoration is done).
• Different blocks.
• Brick.

Each of these materials has advantages and disadvantages.

When constructing the walls of a bath from logs, which have been used for many centuries, the design receives such advantages as:

• The walls are very steam and air permeable.
• The room retains a light aroma, which is emitted by natural wood.
• Low thermal conductivity, which allows you to keep warm and cozy in the building for a long time even in winter. As a result, heating costs will be minimal.

But wooden walls also have certain disadvantages:

• All wooden buildings are subject to shrinkage, which makes it possible to completely finish the bath only six months after its construction.
• To preserve the logs for a long time in an attractive form and special properties, the bath must be well looked after or protected from the harmful effects of harmful environmental influences. In this case, the walls can be faced with bricks and other materials.

When constructing walls from a bar, they have a number of advantages over buildings from logs:

• Lower price.
• It is easier to build from it, especially with your own hands for a person who does not have professional skills.

A bar is a log cut from two sides or from all four.

In this case, the cross section can be:

• Square.
• Rectangular.

Standard material proportions are 2: 1.

The walls of the bathhouse give sediment throughout the year:

• From a bar - 6 centimeters.
• From a log - 12 centimeters.

When building a bath, materials must be chosen carefully. They must be completely safe, heat-resistant, have good characteristics, and it is also desirable that they are not afraid of high humidity.

First of all, this applies to heaters: all rooms are insulated, and the steam room is so especially careful. And it is in this group that it is very difficult to find material that fully meets all the requirements. So far we know only one: foam glass. It has excellent thermal insulation characteristics, is absolutely chemically neutral, does not absorb and is not afraid of moisture in any of its conditions, it is also a steam and hydro insulator. An excellent combination of qualities, but there is a rather significant disadvantage: the price. Quality material originally from Europe. It costs a lot. There is a cheaper option from Belarus. Quality and price are average. And there is cheap (relatively) foam glass from China with dubious characteristics.

Other heat insulators have disadvantages. Widespread hygroscopic, but at the same time it is afraid of moisture: in a wet state it loses most of its properties. If in a wet state it freezes, then after thawing it simply crumbles into dust. In addition, produced in the form of rolls, it emits formaldehyde when heated, which is used in production as a binder.

The second, more or less common insulation, can be used for external insulation. Inside, it is used only in cold rooms. Disadvantage: low density, susceptibility to deformation. And one more thing: it does not allow air or vapor to pass through. Therefore, when using such a heater, ventilation must be very effective.

There is another material that has a higher density than foam and also has better thermal conductivity properties. This is extruded polystyrene foam. But its disadvantage is the high price.

Building materials for a bath

Building materials for a bath

Since time immemorial, the Slavs have a tradition of building a bath near their house. It has survived to this day, despite the fact that new, more modern washing devices have appeared. In order to independently make such a building for yourself, you need to know what materials you need for building a bath. In this article, we will talk in more detail about this component of the entire creation process.

In addition to all this, the bath is a good investment, because it can increase the value of your property. Think for yourself, would you buy an ordinary house or with a steam room? Everything is true, of course, with your steam room. And now we suggest you move on to a more detailed consideration of the required materials.

Construction materials

Important. The bathhouse as a structure is not an easy object.
Therefore, special requirements are imposed on it, which are even more stringent than those of residential buildings.
So, for example, the standards for the electrical safety of baths should deserve special attention, because in the steam room there is high humidity and temperature.

Building materials are bought for the bath, depending on what its individual elements will be. In other words, the specification will depend on what and how the supporting structures and its individual elements will be made.

We will consider construction issues:

• Sten;
• Ceiling;
• Selection of heat insulators;
• Vapor barrier materials;
• Interior decoration.

Of course, these are not all questions, but only the most important ones, which we will consider later in this article.

Building materials for walls

The wall is the basis of any building, its quality will be determined by the service life of the building and the comfortable conditions inside the premises.

Most often, the following materials are used to build a bath:

• Wood . It is the most traditional building material for a bath, which has already proven its usefulness for many centuries. Basically, deciduous tree species are used for construction - cedar, larch, etc. In specialized stores you can purchase the following beams: glued profiled, profiled, rectangular section and solid or rounded logs;

Important. When buying wood planks or logs, you should be aware that storage quality is of great importance.
If the humidity in the warehouse was high, then in the future the log will shrink a lot, and maybe even lead it.

• Arbolit. It is a mixture of organic aggregates and cement. Its characteristics are similar to foam concrete. It is made in the form of blocks, moreover, the technological process is so easy that it can be done directly at the construction site. The only significant drawback is the fear of moisture, therefore, after the construction of the walls, they must be veneered;
• Foam concrete. It has good thermal insulation qualities, is lightweight and does not need a massive foundation. It is sold in the form of blocks, and the masonry of the walls from it is simple and can be done by hand. In addition, foam concrete has the ability to "breathe";
• Brick . I must say that this material for the construction of a bath is far from optimal. Firstly, the walls built from it need massive thermal insulation, Secondly, the work of laying bricks itself is quite laborious and difficult. Thirdly, it is imperative to build an appropriate foundation under such walls;
• Frame construction... The construction instruction says that first the frame of the future building is made using a wooden bar. Then the voids in the walls are filled with a heat insulator and a hydro-barrier is made, for example, with ecowool or foil mineral wool.

After that, the wall is sheathed with sheet materials from the inside and outside. Such construction will take much less time compared to the rest, and with the right materials, its price will delight its owner.

From what material it is better to build a bath, it is up to you to decide, of course, you mainly need to rely on the construction budget. If there is not much money, then it is better to take foam concrete or brick, and if everything is in order with finances, then a tree is better.

Vapor barrier and wall insulation

We have combined these two components into one section because they are related. Thermal insulation materials have only one main task - to retain heat in the room.

Experts believe that basalt analogs are the best insulator, because they have a good coefficient of thermal conductivity, are fire resistant and environmentally friendly. In hardware stores, you can purchase it both in a roll and in a plate.

In addition to it, you can install such insulating building materials for the bath: glass wool, mineral wool, ecowool, foam, polyurethane foam and extruded polystyrene foam.

The vapor barrier is created in order to exclude the penetration of water vapor from, because, when wet, it loses its characteristics. To create it, special films like Izospan or Armofol will fit.

Ceiling

This structure must have the best thermal insulation properties, because large masses of hot steam are concentrated under it.

You can in:

• Hemming. It is made by filing boards on beams that rest on the walls. A layer of vapor barrier, insulation and waterproofing is laid on top of the boards. Then they are sewn up with planks. The structure of such a ceiling is the same as that of the walls in a frame house, so the materials for it can be taken the same as for the walls;
• Grazing. The boards are laid on top of the beams, and steam and heat insulation is laid on them. The latter can be any loose insulation, and from above such a structure can basically not be sheathed with anything. In such a ceiling, the floor beams are outside in the bath;
• Panel. If, after creating the insulating layers, the beams are sheathed with special plates or panels, then this is a panel ceiling. This kind of cladding is hard work because the tiles are large and heavy.

What material is better to build a bathhouse in in this case, it is difficult to answer, but the sheathed ceiling looks much better and more beautiful. If finances do not allow you to do this, then this can be done in the future when finances appear.

Bath decoration

The decoration of the bath directly affects the future atmosphere in it, its safety and comfort. In specialized stores there are many components for finishing work, but it must be said that only wood, and even then not all species, are suitable for finishing.

For example, a steam room and a washing room can be faced with different types of wood, and what is suitable for a washing room is strictly not allowed in a steam room.

What material should be used to build a bathhouse in this case? We answer, it is better from the lining, but again you need to pay special attention to the steam room. Due to the high temperature and its gradual drop, as well as humidity, the use of pine varieties is not allowed.

Firstly, they emit unpleasant odors that spoil the resting process, and secondly, when heated, resin accumulates on their surface, which heats up very much and when you touch it, you can get burned.

It is better to take cedar, abasha, aspen, alder or linden wood for covering the steam room, they are dense in composition and thermally resistant. But even here, when buying them, you need to make sure that there are no knots on the boards, because they will get very hot.

The washing room must be finished with moisture-resistant types of wood; larch is well suited for these purposes. The lining made from it does not give in to decay and has a long service life. As for the dressing room, it can be sheathed with any tree species, if you want to save a little, you can buy spruce and pine boards for these tasks.

Important. If you are thinking about how to build a bath from scrap materials, then you may need to think about using ordinary homemade building blocks.
At one time, home-made blocks called "adobe", which were made from ordinary clay, straw and other components, were in great demand among the population.
But in this case, you should know that such a bath should have ideal vapor and waterproofing, and also that it will last a much shorter term than analogues.

Selection and calculation of material

We think that it will not be a secret for you that more than half of the cost of construction is occupied by the construction of walls. Because the scope of work and materials is concentrated here to the maximum. At this point in our article, we want to give an example of calculating the amount of material that will be required to create walls.

Since the most optimal and preferable option for these works is a wooden beam, the calculation of materials for the construction of a bath will be performed for it.

Let's assume that you have decided to undertake the construction of a small bathhouse with dimensions of 3 by 4 meters and plan to purchase a timber with a size of 150 * 150 mm. In this case, our calculation will look like this:

| (3 + 4) * 2 * 0.15 * 2.5 | * 1.1 = 6 m 3

Where:

• (3 + 4) - width and height of load-bearing walls;
• 2 - the second pair of walls;
• 0.15 - bar height, mm;
• 2.5 - ceiling height;
• 1.1 - 10% stock.

As a result, for a small bath, we need 6 cubes of material. If you are wondering what material is cheaper to build a bath from, then you can multiply this figure in turn by the cost of timber, bricks, foam concrete blocks, and so on.

Conclusion

In this article, we examined the main points of construction, and discussed what material a bath can be built from. It is best to use wood, but if the construction budget is small, then you can turn your attention to other materials. In the video presented in this article, you will find additional information on this topic.

Bath ventilation is divided into general and preserving ventilation. We call preservative ventilation drying a bath after water procedures. If in the bathroom and shower the main difficulty is drying towels and floor mats, then in baths it is most difficult to dry wood, especially on floors and in crevices.
Drying of baths, bathrooms and showers is carried out by aerodynamic methods - dry ventilation air enters the area of ​​humidified materials, evaporating water. Water vapor is released into the air. Through the exhaust ventilation humidified air is removed and fresh air is supplied. Thus, the drying process includes several stages and is far from simple.

Let's make a reservation right away that if we consider the problem broadly, then we should talk not about drying, but about the normalization of wood. The fact is that in dry high-temperature saunas, the wood sometimes does not get wet, but, on the contrary, dries up, and after the end of the bath procedure, it is again moistened due to the equilibrium hygroscopicity. In steam and humid baths, wet wood must also be dried not to an absolutely dry state, but to a certain level of humidity. That is, conservation ventilation is not just wood drying, but drying, taking into account the specific bath process, the characteristics of wood, its possible morbidity and the possible consequences of overdrying (warping, cracking) and underdrying (decay).

Moistened - dry

For all its advantages, wood also has many disadvantages, which makes it a problematic material for baths. Fire hazard, low hygiene and the ability to quickly rot - these are the main features on

natural wood, which at one time put an end to the prospect of using wood in urban public baths for hygienic purposes.

In individual baths, wood continues to be used in a periodic (episodic) mode with mandatory subsequent drying, despite the possible chemical treatment of wood.

Wet wood is susceptible to all three types of biological destruction - due to bacteria, fungi and insects, and dry only due to insects. If wood rot is slimy with an unpleasant odor, it is most likely bacterial rot. If plaque, colors (stains of foreign color), mold with an earthy smell are formed on the wood, these are probably microscopic fungi (fungi, micromycetes). Bacteria and micromycetes are not so dangerous for individual country baths, which will stand for many years even with colors. But for representative and apartment baths, micromycetes are the number one scourge, since they spoil the appearance of the finish. But the most dangerous for baths are macromycetes - large, real mushrooms with characteristic fruit caps, living right on the wood (like mushrooms, tinder fungus, sponges). Many summer residents, with surprise noticing brown fan-shaped mushroom caps sticking out of the floor in their bathhouse, at best, will only scrape them off and lubricate the growing area with vitriol or chromopic, not realizing that these caps are only the fruit bodies of a house wood-destroying mushroom. The mushroom itself is hidden in the floor, walls, foundation (both in a tree and in a brick) in the form of a system of branching threads (single GIFs - cords up to 1 cm in diameter), forming a mycelium several meters in size, so that the development of the fungus can only be stopped antiseptic treatment of large areas. The normal temperature for the development of house mushrooms is 8 - 37 ° С, the relative humidity of the wood is 25 - 70%. Under optimal conditions, the fungus destroys the bath in one season, forming brown fissured rot, which breaks up into large prismatic pieces that are easily ground into powder.

It is believed that the development of the house fungus is suspended when the relative humidity of the wood is about 18% and below. Considering the wood hygroscopicity curves from this point of view, several conclusions can be drawn. Firstly, to maintain the moisture content of wood at 18% and below at all temperatures of fungal development (5 -40 ° C), a relative humidity of no more than 80% is required. Otherwise, even completely dry (but not treated with water-repellent compounds) wood will be moistened above this level by itself (without contact with room water) due to the absorption of moisture from the air. So in tropical countries there are more problems with timber than in the north. Secondly, considering the curves of wood hygroscopicity in other coordinates (Fig. 1), it can be noted that wood, arbitrarily strongly moistened at a temperature of 30 ° C and an absolute air humidity above 0.03 kg / m3 (that is, at a calculated relative humidity air 100% and higher relative to the temperature of the wood), dries at a temperature of 40 ° C to a humidity of 11% (and only up to 11%!), and at a temperature of 80 ° C to a humidity of 2.5% (and only up to 2.5%! ). All this is extremely unusual: non-porous materials would dry out completely under these conditions. For marble, metal and plastic, only two states are possible: when there is water on them (and no matter how much) and when there is no water on them at all.

In this regard, let us recall how dry wood is moistened. If you splash water on a wooden board, it will gradually be absorbed into the depths of the wood: first into the intercellular spaces (vessels, pores between fibers), then into dense (dried) cell cavities, then into the cell walls. All of these pores are capillaries with wettable walls. Due to the formation of concave menisci of water surfaces, the saturated vapor pressure above the water inside the wood is less than above the water poured over the surface. Therefore, not only water, moving along wetting surfaces, but also its vapors rush into capillaries (intercellular and cellular), moisten (and then dry quickly). Water in them is called free, its content in wood can reach 200%. Small capillaries (in the cell walls) are moistened (and then dry) slowly, the water in them is called bound (hygroscopic), its content in wood reaches up to 30% (it is shown in Fig. 1). Thus, a board that looks "dry" without water droplets can contain 100% or more moisture, and this moisture is extracted from the wood in the form of water vapor during drying and can humidify the air. This effect is used not only when drying a bath, it is also used to create a condensation climatic regime in a Russian steam bath, when due to the high relative humidity of the air near the ceiling (for example, when water is supplied to hot stones), the ceiling is first moistened (preferably a massive log). Then, in the periods between giving, a high absolute humidity is created at the ceiling - above 0.05 kg / m3. Under these conditions, a metal ceiling would not just "drip" without retaining moisture, it could only create a quite definite relative humidity of the air at its surface, equal to 100%. A wooden ceiling (like any porous one), in principle, can create only a quite definite relative humidity of the air at its surface, and with a fixed humidity of wood (due to the massiveness of the walls, for example), the relative humidity of the air not only at the ceiling, but also in the room can be maintained also practically constant regardless of how the room temperature changes. The effect of stabilization of the relative humidity of the air in wooden residential buildings (in brick and plastered ones too) is associated in everyday life with the property of wood to "breathe", take moisture from the air and release it into the air in the form of water vapor. So a plastic sauna and a wooden sauna even with the same steam generator give different climatic conditions. Indeed, let us imagine that the sauna is completely dry at a temperature of 20 ° C and at a normal relative humidity of 60% (that is, at an absolute air humidity of 0.01 kg / m3). In accordance with fig. 1, the relative humidity of wood under these conditions is 12%. Now, hypothetically, let us heat this sauna (without ventilation and without humidification) to a temperature of 70 ° C. The bold dashed horizontal arrow in Fig. 1 shows that the absolute humidity in the sauna jumps up to 0.14 kg / m3, just right to steam with a broom! Where did the water come from! The wood began to dry and humidified the air. By the way, it is the water vapors coming out of the wood that "pull" the "smells of wood" that are so appreciated in apartment saunas. This phenomenon serves as another additional reason for the need to ventilate even dry apartment saunas, so that they do not unexpectedly become steam rooms. And if the sauna is ventilated during heating with fresh air of the same absolute humidity of 0.01 kg / m3, then the air in the bath will be kept dry, and the moisture content of the wood in the bath will decrease and sooner or later will drop to 1% (see vertical bold dashed arrow in Fig. 1), that is, as they say in everyday life, the boards "dry up". And then, after the end of the bath procedure, they will be moistened again due to the sorption of air moisture to a moisture content of 12%. In the language of meteorologists, "wood tries to keep the relative humidity of the air constant." Indeed, in the wooden bath discussed above, the wood "kept" the relative humidity in the bath at 60%, which can be achieved under conditions of a rise in temperature only by humidifying the air with wood. There can be nothing like this in a plastic bath: when it is heated, the absolute humidity of the air remains constant, but the relative humidity drops. It is glass, sheet metal and plastic that are ideal materials for dry physiotherapy and room saunas. And if you use wood, then only thin, specially treated to prevent hygroscopic absorption of moisture from the air. The craze for decorative wooden finishing of baths (not always justified) leads to the fact that even bath hygrometers are sometimes made in wooden cases (!), "Keeping" the relative humidity inside themselves constant, regardless of the temperature and true humidity in the bath. By the way, recall that the measuring thread of the hygrometer, located inside the case, stretches when wetted (like an ordinary woolen thread) and thereby shows how wet it is. And it is moistened hygroscopically (due to its porosity) according to the same laws as wood. That is, the thread is moistened and lengthened mainly only when the relative humidity of the air changes. This is the basis of the principle of operation of hygrometers with natural thread. By the way, wood fibers stretch and shrink only when the relative humidity of the air changes. In rural life, the simplest, but very accurate "hygrometers" in the form of a thin, peeled and dried bifurcated wooden branch are well known. A thick mustache (the main branch is about 1 cm thick) is cut 10 cm above and below the fork and vertically nailed to the wall (baths, houses, cellars). A thin mustache (shoot about 0.3 cm thick and 0.5 m long) is directed upwards parallel to the wall. In dry weather, a long thin mustache of a branch slopes, moves away from a thick one ("bulges" with an increase in the acute angle of the fork), and if it rains, it approaches a thick one. If you have a certified industrial hygrometer, then this homemade hygrometer can be calibrated with marks on the wall opposite the location of the tip of the thin mustache at different relative humidity. The principle of operation of such a hygrometer is that during drying, the underlying wood fibers of the main branch are shortened and pull the shoot down (from the trunk of the main branch).

Thus, the processes of moistening and drying wood take place in the bath not only on the floors due to compact water and are associated not only with bath procedures. If wood can be moistened with both compact water and water vapor, then it can be dried only by removing water vapor from it. The drying process takes place in several stages. First, water evaporates on the surface of the wood, then free water in the large capillaries of the intercellular and intracellular spaces, then water in the small capillaries of the cell walls. The latter, as we established above, determines the hygroscopic moisture content of wood, which exists and changes even in a dry, unheated bath. Therefore, the drying of the cell walls can actually be controlled in the greenhouse conditions of dry built-in saunas, although bound water, in principle, can support the processes of decay of wood, especially, as we have noted, in warm and humid climatic conditions.

The step-by-step drying process is also typical for other porous materials, including bricks, plaster and soil (earth). Drying them is also important for the bath, if they are part of it. In this regard, we recall the fundamental, although related only indirectly to the topic of the article, the question of the mechanical deformation of porous bodies during the primary removal of bound water from them. It is known that warping and cracking of freshly cut wood occurs during the drying process, mainly in the last final stage, when hygroscopic moisture is removed from the cell walls. If, during the initial drying, the board is nailed or clamped in a vice, then it will retain the shape given to it (for example, arcs), and the better, the better the wood is dried. Under the conditions of primary natural atmospheric drying at 20-30 ° C, wood is dried only to a moisture content of 10-15% (after 2-3 years of drying), and with high-temperature stone drying at 100-150 ° C (including in a bath ) can be dried to a moisture content of 1 - 2 96. With such a significant dehydration, especially at high temperatures, irreversible changes occur in the cell walls, and the wood actually ceases to be wood and begins to exhibit the properties of inanimate material. Similarly, clay soaked in water, during drying and heat treatment, first loses its plasticity, then cracks, and then becomes a brick, which does not change its shape and properties in the future upon contact with water. also by immersion in a hot anhydrous heat carrier (paraffin, oil products).

The mechanism of primary drying of freshly cut wood differs in that the walls of its cells have not yet been destroyed, the vapor and water permeability of the membranes is low and the wood dries for a long time, deforming during the destruction of the integrity of the cell wall membranes (and they, in fact, are wood - a combination of cellulose, lignin and hemicellulose). In the course of subsequent dryings, the wood dries faster and already behaves like "lifeless", since the cell walls have already been torn. At the same time, dry wood as a porous material has specific features that distinguish it from other materials, in particular, anisotropy of properties, secondary warpage, etc.

Drying dynamics

Water spilled on the surface of the wood evaporates in the same way as water poured into a bathtub or pool. Recall that there are two opposite modes of evaporation - kinetic and diffusion. In the kinetic regime, the fastest molecules, overcoming an energy barrier equal to the latent heat of evaporation (condensation) 539 cal / g, fly out from the surface of compact (liquid) water and are irrevocably removed. The kinetic regime is realized during evaporation in a vacuum. Due to the high speed of the primary act of vaporization (the release of water molecules from the surface of compact water), which at bath temperatures amounts to thousands of kilograms of water per hour from 1 m2, the water is strongly cooled (since only slow molecules remain in it) until it turns into ice, which is used in freeze drying in industry. In the diffusion mode, the primary act of vaporization remains the same and is just as strongly dependent on temperature. But the escaping water molecules enter the air (a mixture of nitrogen and oxygen molecules) and, as a result of frequent collisions, only very slowly move away (diffuse) from the water surface, experiencing strong resistance from the air environment. As a result, the overwhelming number of escaped molecules again "flies" into the water (condenses). Thus, in the diffusion mode, tons of water turn into steam and immediately condense (which we do not feel in any way), and only a very small amount of water (kilograms) completely evaporates. It is this diffusion mode of evaporation that takes place in a bath: both when sweat evaporates from the human body, and when water evaporates from the shelf. It becomes clear that if the concentration of water vapor molecules everywhere in the bath is equal (including at the surface of the human body), then no evaporation processes are possible (homothermal mode). But at the same time, it becomes clear that if tons of water per hour evaporate and condense in the bath at the same time, then we can assume that this should manifest itself sometime. Indeed, if the air in the bath is dried, then the rate of evaporation of water will increase. If the surface of the water is blown with dried air, then the evaporation rate will increase even more, since the air stream removes those molecules of water vapor that previously condensed. For orientation, we point out that at a relative humidity of 5096, the rate of evaporation of water at a temperature of 30 ° C is approximately 0.1 kg / m2 / hour. When air moves at a speed of 1 m / s, the evaporation rate approximately doubles, however, it should be noted that the air speed in a room is always much higher than directly above the water surface, and all quantitative indicators are extremely indicative. Experimental pool formulas can be used for estimates. In any case, the characteristic rate of drying floors in baths is 0.1-1 mm / h (0.1-1 kg / m2 / h) increases with an increase in the floor temperature and with a decrease in air temperature (that is, with a decrease in the absolute humidity of the air). So, for example, in open pools at a constant water temperature, evaporation is maximal not at all during the day, but at night in cold air, as well as in winter. In the daytime, in hot weather, evaporation may stop, even condensation of water vapor from the air on the surface of the pool may be observed, just as water condenses on human skin in a condensation-type steam bath in a mode higher than a homothermal one. For any pool with a certain water temperature, any floor, wall and ceiling, each bath has its own "homo-thermal" curve that separates the modes of water evaporation and condensation of water vapor, summarizing the above processes of evaporation and condensation on the water surface. Let's call it conditionally condensation. In terms of condensation curves, drying looks like this. In fig. 2 shows the condensation curves for a floor with a temperature of 20 ° C (curve 1) and for a ceiling of a steam bath with a temperature of 40 ° C (curve 2). The modes below the curve correspond to the evaporation of water, the modes above the curve correspond to the condensation of water vapor on the surface of the given temperature. Thus, if the air in the bath has a temperature of 40 ° C and a relative humidity of 6096 (it does not matter whether the air in the bath is stationary, whether it circulates or enters from the outside in the form of ventilation), then in this mode (point 3) the ceiling is dried and the floor is moistened. ... In other words, air with such parameters transfers water from the ceiling to the floor, but even if the ceiling were dry, the floor would still take moisture from the air, that is, dry it (in this case, to a relative humidity of 40%). The floor can be dried only if you reduce either the air temperature or its relative humidity, or better both, so that the air characteristics are below curve 1, for example, if the mode corresponding to point 4 is implemented. The fact of possible air movement (blowing the floor) does not change the quality picture, but only affects the rate of evaporation or condensation. By the way, it is this very mechanism that works in case of catastrophic humidification of the subfields of a residential building, to which a bathhouse with leaking floors is attached. Warm, humid air from the hot water discharged to the ground spreads over long distances and produces condensation on the cold subfloors and foundations of the entire apartment building.

The main conclusion is that conservation ventilation is not just a change of air in a damp bath room. It is necessary to supply air with the lowest possible temperature and relative humidity, or rather the lowest possible absolute humidity. In addition, it is necessary to keep the surfaces to be dried as warm as possible, and the higher the absolute humidity of the air, the higher the temperature of the surface to be dried. This means that it is not the air that needs to be heated, but the floor of the bath, for example, with infrared radiation. And if, nevertheless, it is possible to warm only the air, then it must be dried, as is done in washing machines and dishwashers. Note that the sometimes recommended methods of drying a bath with the release of hot humid air through the floor in the underground lead only to additional humidification of the cold (and therefore the most problematic) elements of the bath. Better to release hot, humid air through the upper vents, in which condensation is impossible. In fact, in almost all baths general ventilation is used for conservative drying of the interior.

With the complete evaporation of water from the surface of non-porous materials, drying can be considered complete. But when we are dealing with wood, it is also necessary to remove the internal water. If the wood is treated with water-repellent compounds, then the pore walls are not wetted with water, which means that the water vapor pressure in the pores is greater than on the wood surface. This leads to the "evaporation" of water from the pores on the surface of the wood in the form of droplets, which then evaporate again as described above.

Water filling pores with wetted walls, including untreated wood, evaporates in a diffusion mode, and the removal of steam is extremely difficult. Although wood contains 50 - 90% of voids, the tortuosity of the pores leads to the fact that the real path of removal of water molecules can be several times larger than the characteristic dimensions (thickness) of a wood product. In this case, possible air flows, even very small ones, can strongly influence the drying rate. The "permeability" of materials is characterized by a parameter called vapor permeability, equal, for example, for mineral wool 8 - 17, for pine along the grain -10, pine across the grain - 2, brick - 2, concrete - 1 in units of 10 "6 kg / m / sec / atm.So, with typical static pressure drops due to wind of 104 atm.real values ​​of drying rates for porous materials with a thickness of 10 cm at 20 ° C are less than 1 g / m2 / day for vapor-insulating materials (hydraulic concrete, asbestos cement, extruded polystyrene foam ), 1-20 g / m2 / day for vapor-permeable materials (wood, brick, plaster), more than 20 g / m2 / day for vapor-permeable materials (mineral wool), more than 1000 g / m2 per day for superdiffusion materials (perforated membranes The rate of drying increases with an increase in the temperature of the wood, with a decrease in the temperature and humidity of the blown air, just as in the case of evaporation of water from the surface. experimentally, depending on the degree of moisture and the season, but the temperature of the internal elements of the bath has a much greater influence. The analysis of wood drying issues could be continued and the most reasonable solutions for preservative ventilation could be considered. But there is no point in deceiving: the centuries-old experience of operating wooden baths shows that no matter how sushi the wooden floors are, there are still no guarantees of drying quality, they still rot. Indeed, if 1 m2 of a wooden floor conditionally absorbs 1 kg of water, then drying it at a rate of 20 g / m2 will last 50 days. Therefore, wherever possible (and not only in baths), wood is covered with roofs, awnings, but in this case it is also capable of moistening. condensation from the air (for example, under iron roofs) and rot (brown, darken, crumble), especially in poorly ventilated places. The presence of air vents, that is, holes and slots larger than 3-5 mm, is an indispensable condition for the preservation of unheated zones of wooden structures. On the contrary, airs with a size of less than 1-3 mm are stagnant, poorly ventilated zones, moisture evaporates from them slowly, which creates conditions for rapid decay, especially in contact with vapor-impermeable materials, and even more so with constantly humidified ones. The question is not about how to dry wood qualitatively, but about how to remove it from the bath altogether or reduce its wetting and reduce the rate of decay. This is typical not only for wood, but also for all porous mineral materials (brick, foam concrete, gypsum) and rusting steel. After all, no one makes floors from foam concrete and then makes incredible efforts to dry it. Likewise, rusting steel is painted, rather than trying to dry quickly after each rain. In modern saunas, all wood that can come into contact with water must be impregnated with water-repellent compounds (preferably under pressure, as is done in the case of railway sleepers and ship masts), and protected from above with waterproof paint and varnish coatings, as well as shelters, not to mention antiseptic and fire protection. The wood in the bath is a problematic material, and the widespread opinion that the bath is good only because it is wooden and there should not be any "chemistry" in it is absolutely groundless. Of course, in the conditions of a built-in amusing sauna, operated in the greenhouse environment of an apartment corridor, untreated wood is permissible even on the floors, but even there only in the form of a removable, dried grate.

STEAM INSULATION OF CEILINGS

Methodically more difficult is the question of ventilation of wood in the upper parts of the walls and ceiling. The task of preservative ventilation here is to supply dry air to humidified areas to dry them. Therefore, in each specific case, it is necessary to clarify what and how can be humidified, and only then decide where and how to supply the ventilation air.

The ceiling (or rather, the ceiling slab) can be moistened by precipitation in case of emergency roof leaks and steam condensation. Previously, humidification was predominant due to trivial leaks, since until the 19th century in cities and until the 20th century, there were no bath roofs in the villages, except for wooden (boards, shingles), straw and Kamyshevs. Log walls and ceilings could absorb hundreds of liters of water in case of a malfunction of the roof. Therefore, there was no need to talk about any possibility of their periodic drying after constant leaks, although the wooden roof itself worked precisely in this mode of constant moistening and drying (as a result of which the wooden roof was made thinner so that it got less wet). The task was simple: to prevent leaks, but if they happened by chance, then the walls and ceiling had to be dried sooner or later, but be sure to dry them. This was achieved by constant ventilation of the attic space, by organizing air vents, gaps and cracks in log and plank structures wherever possible, that is, the same techniques were used as in the natural drying of firewood in woodpieces, but, of course, while maintaining the heat-insulating ability of the walls and ceiling.

Currently, individual developers do not take leaks seriously, relying on the reliability of steel and slate roofs, although the issue remains serious and the consequences are most dangerous. So what happened, as a result of which everyone around began to talk about the indispensable need to vapor barrier the walls and ceilings of the bath as the most important thing? Indeed, for centuries before, in black logs, and then in white steam baths, they did not know about any vapor barrier, and steam humidification is so insignificant in comparison with leaks that they cannot create a dangerous moisture level of wood above 18 percent for a long time (especially in dry built-in saunas ).

Immediately, we note that the issue of vapor protection of wood and heaters first arose in baths in connection with the appearance in everyday life of soft waterproofing roofing materials (which are also often used not for their intended purpose), and dangerous levels of wood moisture have acquired an exclusively local long-term nature. However, before moving on to this issue, let us consider the general features of moistening wood with condensing steam.

Usually in the literature, the humidification process is described briefly and simplistically: humid air is filtered through porous wood from the inside to the outside, and where the temperature of the wood drops to the dew point of humid bath air of 40 ° C, local condensation of steam occurs and the wood is humidified only at this point. In fact, the process is more complicated. Firstly, wood is a wettable porous material; therefore, the condensate released is absorbed by the wood and is distributed over the wettable pore walls over a large volume of wood (blotting effect). By the way, then l<е самое происходит и в других смачивающихся пористых материалах: кирпичных, гипсовых, пенобетонных. Во-вторых, древесина является непросто смачивающимся пористым материалом, она имеет и мелкопористую составляющую, обуславливающую гигроскопичность материала (способность впитывать пары воды из воздуха). Для таких материалов характерно отсутствие четкой точки конденсации. На рисунке 3 изображена еще раз перестроенная в иных координатах кривая равновесной гигроскопичности древесины в зависимости от температуры. Это фактически график влажности древесины по срезу стены бани, имеющей температуру внутренней поверхности стены - 100°С (справа) и температуру наружной поверхности стены - 0°С (слева), при условии движения влажного воздуха изнутри наружу (справа налево). Мы видим, что при влажности воздуха, например, 0,05 кг/м3 (точка росы 40°С) равновесная влажность древесины на внутренней стороне стены равна 2 процента, затем по мере углубления в стену влажность древесины плавно, но быстро повышается и по мере приближения к точке росы 40°С резко возрастает до бесконечности. Это означает начало конденсации в крупных порах, но вся вода из воздуха в этой точке росы отнюдь не выделяется. Несколько осушившись, воздух продолжает перемещаться влево, непрерывно и постепенно отдавая воду уже при новых пониженных точках росы (например при влажности 0,017 кг/м3. Таким образом, увлажняется довольно протяженная зона, причем находящаяся у внешней стороны стены, которая впоследствии высыхает с выделением водяных паров наружу, но которая отнюдь не прогревается горячим воздухом при сушке интерьера бани. Так что очень большое значение имеет не столько температура воздуха в бане при ее сушке, сколько сухость этого воздуха, а также направление движения воздуха, фильтрующегося через стенку.

If the wall material is not fine-pored (for example, like mineral wool, which practically does not have capillaries) or if the material is treated inside with a water-repellent agent and is not wetted, then the wood moisture curve is converted into a vertical dotted line at a dew point of 40 ° C, that is, at temperatures above dew point such a non-hygroscopic material does not absorb moisture from the air at all, and at temperatures equal to the dew point and below, constant condensation of moisture from the air occurs in the same way as described above. However, in the case of non-wetting of the inner surfaces of the porous material, the released condensate cannot be distributed over large volumes of walls (that is, it cannot be absorbed) and inevitably accumulates in separate zones, including forming droplets. When using mineral wool, drops of condensate flow in streams onto the lower elements of building structures, for example, on wooden beams, logs, crowns, greatly moistening them. In any case, in vapor-permeable (air-permeable) walls, it is advisable to make ventilation ducts (air vents) in areas near the dew point, as well as near load-bearing wooden elements. In particular, a good solution is to upholster the log house with planks (boards, clapboard, siding) inside and outside so that the gap between the boards and logs plays the role of steam exhaust ducts (ventilating facade).

Needless to say, there has always been a desire to keep water out of the walls at all.

So, in particular, in stone (brick) city baths, the walls remained moist for years, despite the ventilation. Therefore, the inner surfaces of the walls, wherever possible, were protected by ceramic tiles, paintwork, natural stone. Of great importance was the introduction into everyday life of cheap soft roll waterproofing vapor-proof materials, including roofing materials (first - roofing felt based on wood or coal tar, then - roofing felt and glassine based on bitumen-rubber mastics, synthetic polymer films and metal sheet foil). They began to be widely used in individual rural baths, first for their intended purpose - as roofing, and then to protect the outer sides of ceilings and walls from rain and wind, especially frame ones, insulated with non-waterproof materials (moss, paper, shavings, fiber boards, arbolite, cross-section straw moistened with glass wool). It is quite natural to want to cover, for example, a layer of shavings lying on top of the ceiling with something impervious or to upholster the plank walls of the bathhouse outside with roofing material to protect it from wind and rain. As a result, the shavings, which were previously moistened only with rare leaks, and when moistened under the action of steam penetrating from the bath, immediately dried out, under a layer of roofing material, they lost the ability to dry out after any moistening. More precisely, the shavings under the roofing felt can dry only when the moisture is removed back to the bath, which is very difficult. Therefore, between the shavings and the roofing material, it is necessary to make a ventilated gap (air) or make punctures in the roofing material for ventilation. Instead of roofing material, special roll materials, called windproof, were developed for these purposes. They do not allow compact water (raindrops) to pass through due to non-wetting and at the same time slightly allow air with water vapor due to porosity or perforation, but protect against gusts of wind. It should be noted that wind gusts create pressure drops up to 10 "atm., Exceeding the pressure drops due to air heating in the bath 10 5 atm., Therefore, the wind pressure certainly plays the main role for drying the walls. It is these pressures that are saved by windproof materials, although air The fact is that the gas-dynamic resistance of the windproof material is much less than the gas-dynamic resistance of the protected wall of logs. Therefore, the logs practically do not "feel" the windproof material. At the same time, if the wall is not made of logs, but from an easily blown insulation , then here wind protection plays a decisive role, limiting the speed of the air flow through the wall. The simplest windproof is the traditional upholstery of the walls with clapboard (boards), so that the upholstery can play not only a purely decorative and hygienic role.

At the same time, windproof materials cannot completely solve the problem of humidification. Indeed, covering the shavings on the ceiling with a windproof material, we will only be sure that an accidental roof leak will not moisten the shavings, and if it nevertheless gets wet (in any way), it will dry up sooner or later. But if the temperature of the wind protection layer is below the dew point, then moisture will condense on this layer, which in a liquid state cannot pass through the wind protection. Since moisture enters the windproof material in the form of steam in the air flow from the inside to the outside, it is advisable to protect the ceiling from the inside with a vapor-insulating layer (airtight film). Such a sandwich-type structure with three layers (wind protection - insulation - vapor barrier) is the basis of modern enclosing structures. A general technical requirement is to install vapor barriers in areas with temperatures above the dew point. If the vapor barrier is made in the form of a wall cladding (plastic, steel, ceramic), then questions about its installation usually do not arise. But what if the vapor-proof film is placed inside the walls? For example, is it necessary to make a gap between aluminum foil and decorative clapboard? The answer is simple: if compact water can be there, then a ventilated gap is necessary. For example, it is very difficult to make a gap on the ceiling. And if you open the ceiling of a steam bath after several years of operation, you will see that where there was no water (in the center of the ceiling), the back (top) side of the lining is absolutely fresh. And closer to the walls, where there could be water, there are dark spots of damaged wood.

The vapor barrier prevents the penetration of steam into the wall, but at the same time stops the through-blowing of the walls and, thereby, makes it difficult to dry them when the roof is leaking. Therefore, having prevented the penetration of steam, it is still desirable to restore the possibility of blowing through the wall by organizing air vents along the outer, and preferably along the inner side of the vapor barrier, although the general ventilation of the room can take on the role of preserving ventilation on the inner side. In this case, the supply and exhaust openings of the air vents should go out into the street or rooms adjacent to the bath (dressing room, vestibule). To assess the required dimensions of the airflow, consider a log bath with a volume of 10 m3 and an area of ​​enclosing structures of 25 m2. Let us take the degree of emergency humidification equal to 20 kg of water. Based on the characteristic vapor permeability of log walls at the level of 20 g / m2-day, the duration of natural drying in diffusion mode at wall temperatures of 10 - 20 ° C will not exceed 40 days (the value is quite large). In the presence of a vapor barrier of logs, such a duration of wall drying can be achieved at a wall ventilation rate of 1 m3 / hour, which is significantly lower than the ventilation rates of the bath rooms - 10 m3 / hour or more. Such a speed can be provided by the supply and exhaust openings of the air vents between the logs and the vapor barrier, the total cross-sectional area of ​​10-50 cm2, that is, in fact, slots (along the entire perimeter of the bath), less than 1 mm wide, which is ensured by inaccuracies in the mechanical processing of wood and assembly of structures ...

In log walls, wood plays the role of both windproof, heat-insulating, and load-bearing material. The modern construction of construction, including multi-storey buildings, implies the development of insulating materials for narrowly specialized functions and only sometimes combined functions. So, for example, waterproofing, windproof, vapor barrier, thermal insulation materials are, as a rule, completely different materials. At the same time, specialized film (roll) and tubular (cord) moisture-removing materials that can be laid inside the walls and which, playing the role of air vents, could remove moisture from the most difficult-to-reach places in any form (in the form of compact water or in the form of steam). It is these drainage materials that, apparently, will become in the future the basis of progressive solutions for the preservative ventilation of walls. Indeed, how to dry (or keep dry) massive brick walls that have been damp for years, the walls of city public baths, laundries, swimming pools? Neither elevated bath temperatures nor maintaining a relative humidity of 40-60 percent in laundries and swimming pools can completely ensure the dryness of walls, even those protected by ceramic tiles. Recently, hollow building materials (slotted bricks and concrete blocks with cavities, foam materials) have begun to be widely used, but these voids in the walls must somehow be connected to each other and closed to centralized supply and exhaust devices that regulate the speed of preservative ventilation within the required limits. This role will be assumed by new ventilation materials, primarily in ventilated facades and roofs.

One way or another, using ultra-modern or traditional materials and structures, it is necessary to provide air vents (ventilation ducts) in all places of walls and ceilings where compact water can appear. The transverse size of the vents (slots - 1 mm or holes with a diameter of 3-10 mm) is not so important, the main thing is that the vents cover all problematic parts of the walls (especially supporting structures) and are ventilated exclusively with outside air under the influence of wind back pressure. With a large size of air vents, it is advisable to close the ventilation ducts to local supply and exhaust openings, the flow sections of which can be adjusted if necessary. It is not advisable to combine the supply and exhaust ventilation of the bath room with the wall ventilation system due to the possible increased humidification of the walls with humid bath air.