Every owner wants to have a bathhouse in his backyard, so these household buildings are often erected before the construction of the main house is completed. And, despite the fact that it is much easier to equip a country cottage with a modern bathroom with a hydromassage system or a mini-sauna with a Turkish bath and a tropical shower, many homeowners prefer to build a free-standing bathhouse equipped with a stove-heater, steam rooms, and sometimes supplement it next to located swimming pool.

When implementing these plans, the owner of the site, first of all, faces the following questions: what material for the construction of a bath will be optimal, where to get it, how much it will be needed, and who will carry out the construction of the bath itself and equipping the bath rooms.

What materials are used to build a bath

When deciding on the construction of a bath, you must remember that it is quite complicated. engineering structure requiring compliance with sufficiently stringent measures to ensure safety during operation. At the same time, the question of what material is better for building a bath is, to a certain extent, quite prosaic. Not a single room for washing and taking bath procedures can be built from one material. Additional building and finishing materials will be required for pouring the foundation, heat and vapor barrier, and roofing.

When choosing the best material for building a bath, they can be divided into the following categories:

• wall materials;
• heat-vapor-waterproofing roll or sheet products;
• roofing materials;
• finishing products.

Of course, major costs and labor will be required to build walls. Today, depending on the region, the soil-climatic zone, the financial capabilities of the owner, for the construction of a wall structure of a bathhouse on the site, the following are most often used:

• mineral building materials - brick, gas silicate blocks, natural sawn stone;
• wood - sanded log, ordinary, profiled or rounded timber;
• wood concrete, which is a frozen cement mortar filled with wood waste - usually wood chips or sawdust;
• frame structures, for the manufacture of which various materials can be used.

Some gardeners and summer residents brag about the fact that they managed to build a bathhouse from improvised materials.

Paying tribute to the cheapness of such construction, it should immediately be noted that it is impossible to build a comfortable washing and steam room from the boards, boxes and plywood left over from the main construction.

Currently, completely new materials are used for the construction of a bath, news about the practicality and durability of which can be found on the relevant forums, information resources and construction portals in the Internet.

It is generally accepted that the best material for the construction of a bath is a tree that can be used to build walls, equip floors, ceilings and for the manufacture of elements of a truss, roof structure.

Features of wooden baths

When choosing a finishing material, the greatest attention is paid to products intended for lining the steam room and washing compartment. There should be no knots in the wagon board, because with several cycles of heating-cooling and wetting-drying, these knots will definitely fall out, giving the wall panels an unaesthetic appearance.

Lining made of linden, alder, aspen and maple has received the greatest distribution for interior decoration.

Of course, you can use beech, cedar or oak lining, but its cost is much higher.

When facing the walls of the entrance vestibule and the locker room, no special requirements are imposed on finishing materials. Here you can use any lining or edged, tongue-and-groove board, subsequently treating it with stain, soaking it with drying oil and varnishing it.

The greatest difficulty in the construction of a bath is the choice of material during the arrangement. The floor surface works in more severe temperature conditions. From below, it is exposed to atmospheric temperatures, and inside it perceives the temperature and excess humidity of the steam room. For the durability of floors, you should not only choose the most quality materials, but even when laying them, it is necessary to provide for all measures to ensure high-quality hydro-steam-thermal insulation.

You should not think that the choice of materials for the construction of a bath ends after the construction of walls, arrangement of the roof and flooring. The homeowner has yet to choose the type of heater and purchase materials for its construction.

Owners country houses sooner or later think about building a bath. After all, the bath perfect place recreation. There you can easily cleanse your body and soul, have fun with friends and family, get a charge positive emotions and health effect.

The efficiency, aesthetics and durability of the building directly depends on the building materials. The bath is built from wood, brick, blocks, etc.. Let's consider the popular options for building materials separately.

wooden bath

The traditional and most rational construction option. Wood - natural environmentally friendly safe material, which will enhance the healing effect of bath procedures. Pleasant forest scent and attractive appearance create a cozy and welcoming atmosphere.

Characteristics of wooden building materials:

• Environmentally friendly materials do not emit harmful toxic substances;
• The tree is easy to install. Mounting wooden frame will take 1-2 weeks;
• Keeps warm for a long time;
• At proper care the bath will last 70-80 years;
• Aesthetically attractive appearance;
• Light weight does not require an expensive deep foundation, which reduces construction costs;
• It does not require external and serious interior decoration, which saves a large part of the budget. After all, finishing is 50-70% of the cost of building a building;
• Ease of processing - wood is easy to varnish and paint any color;
• The low cost of the material due to the availability of raw materials.

For a wooden bath, choose a log or timber. Both of these materials have the above listed features, but there are differences between them. First of all, they relate to the appearance and form.

The rounded log will be appreciated by lovers of the Russian style and spaciousness. The material of the correct cylindrical shape will harmoniously fit into the environment and create a refined appearance of the building.

Glued or profiled timber is characterized by a square shape, which will create a practical European style.

The choice of timber or logs is a matter of taste. However, keep in mind that the construction of a log bath will be cheaper. After all, the beam requires additional costs for interior decoration in order to avoid the appearance of cracks and cracks.

Brick is distinguished by high thermal conductivity. Therefore, reinforced thermal insulation of the walls is required. After all, long-term preservation of heat in the room is the main thing for a bath. In addition, laying brick walls requires a lot of physical effort and takes a lot of time.

Characteristics of brick building materials:

• Durability and strength of the material;
• Requires a deep and expensive foundation, which increases the cost of construction;
• Heavy and laborious installation;
• Requires serious interior decoration and laying reinforced thermal insulation due to high thermal conductivity;
• The material takes longer to warm up;
• Easily absorbs and passes moisture;
• Fire resistance.

Thus, brick building is not the most the best way. It will take a long time and require a lot of effort. In addition, such a bath requires a serious foundation and careful finishing.

Bath from foam concrete blocks

Foam concrete is made in the form of blocks. The material surpasses brick in terms of thermal insulation quality and saves foundation costs. However, the microclimate in such a bath will be completely different than in a wooden one.

Characteristics of foam concrete:

• Standard wall foam block replaces 13 silicate bricks;
• Ease of installation - the foam block is easy to install on your own without professional training;
• Damp resistance;
• Difficulties in installing ventilation and vapor barrier.

Foam blocks are more suitable for building a bath than brick. However, the healing effect in such a room is significantly reduced than in a natural bath. At the same time, foam concrete makes it difficult to carry out vapor barrier and ventilation.

Frame construction - walls in the form of a lattice of timber of various sections. The cells of the frame are filled with heat-insulating materials and sheathed outside and inside with boards, clapboard or imitation timber.

Characteristics of frame technology:

• Ease and speed of erection;
• Good thermal insulation;
• The light weight of the structure does not require a deep, expensive foundation;
• Cheap materials and construction;
• Structural fragility.

A frame bath will not require large expenditures. However, a fragile structure will last much lower than a bath made of wood, brick or block.

What material is better for building a bath

Regardless of the choice of material, wood will have to be used in any case. For sheathing walls and ceilings, a wooden lining is required, for laying a shelf - boards. Internal partitions, doors and window frames, deck chairs and shelves, cooperage products - all this is made of wood. Is it worth spoiling the atmosphere with artificial materials?

A solid wooden bath will last a long time and create a unique atmosphere. The tree perfectly retains heat and has a beneficial effect on the human condition. In such a room it will be easy to breathe and pleasant to be.

The MariSrub company offers dozens of turnkey log bath projects. In the catalog you will find projects with an attic, a terrace, a rest room. For you - baths of various sizes and layouts. Let's do it individual project taking into account the characteristics land plot and wishes of the client.

The choice of material for the construction of a bath and interior decoration largely determines the quality and appearance of the bath. As it turned out, in addition to tastes, material possibilities, traditions, it is necessary to take into account a number of factors that leave their mark on the choice of building material, so in this article we will consider what materials are best used for building a bath.

What material is the bath made of?

• rounded logs;
• beam;
• brick;
• concrete;
• various types of panels.

The best material for a bath - Log walls

Most often, baths are built of wood. Special attention given to the strength and quality of the material: any irregularities or places of loose fit can cause significant heat loss.

You can talk endlessly about the advantages of a log sauna, and the best material for a bath:

• Aesthetics. For many, when choosing between a timber log building, aesthetics is one of the main factors.
• Environmental friendliness. Wood is an environmentally friendly material, absolutely safe for humans.
• Low thermal conductivity. Long-term heat retention is ensured due to the low thermal conductivity of wood compared to other materials (brick, concrete, panel). There is no need for additional thermal insulation.
• Durability. According to this criterion, baths made of timber are significantly superior to panel and frame buildings. Durability depends on many factors - from the selection, harvesting and storage of wood and ending with the care of the building. Subject to the construction technology of the bath, proper and timely care, such a bath will last for a long time. Estimated term, subject to all norms, is 75 years.
• Low cost. Planed wood is a relatively inexpensive material, and the cost of building from it is much lower compared to the cost of brick bath. Coniferous species are mainly used for the construction of baths - pine, larch. Pine is distinguished by a small number of knots and the greatest straightness of the trunk. Larch is denser than pine and more resistant to decay, resistant to dampness, but its price is higher compared to pine.

As for the fire safety of a wooden bath, here, of course, a lot depends on compliance with building standards. To increase fire resistance, wood is impregnated with flame retardants, the choice of which is huge.

Building material for a bath - Timber

However, the construction of a bathhouse in a summer cottage can be carried out in another way - using not logs, but timber. Such construction reduces material costs. But, on the other hand, if the owner has a desire to ennoble the appearance of the building, he will have to spend money on finishing material..

If we talk about preferences when choosing between a beam and a log, then usually a log is considered more acceptable material for the construction of a bath. However, it would be wrong to say that a log bath is better than a log sauna. These materials for the construction of a bath have approximately the same characteristics, so the preferences in choosing are rather arbitrary and are determined by the appearance and cost.

Brick walls for the construction of a bath

Build a good bath from brick and stone is more difficult than from wood. However, in some cases, when brick and stone are more accessible than wood, it is necessary to build from them not only the foundation, but also the walls. Using brick during construction, it is possible to maintain a high temperature in the room during the day, however, such material will warm up much longer. brick bath more durable and less flammable. Its main disadvantage is large heat losses due to high thermal conductivity. To reduce it, it is recommended to sheathe the inside of the bath with clapboard, laying a thick layer of steam and thermal insulation between it and the brick wall. Any brickwork absorbs and passes moisture, so the contact of the walls with the ground is not allowed.

Moisture-resistant materials for a bath include:

• moisture resistant drywall, used in interior decoration baths and requires additional primer;
• moisture resistant panels.

Bath concrete walls

The microclimate in a brick or concrete bath, of course, will not be the same as in a wooden one. It is possible to build a bath from foam concrete, but vapor barrier and ventilation from inside the premises in this case require perfect performance, otherwise it is better not to use foam concrete.

When performing masonry work from a foam block, it is necessary to remember about the additional waterproofing of the material. It can be bituminous soil (liquid bitumen) with preliminary treatment with deep impregnation soil.

During the panel construction of a bath external walls erected on a frame basis of sandwich panels. So far, this option for building a bath is not popular, although it allows you to save on the basis of the design. Due to the lightness of the walls being erected, it will be enough for a panel bath

Currently gaining more and more popularity Canadian technology construction of country houses from OSB sandwich panels. From this material you can build a bath and such a bath will have a number of advantages:

• construction time is very short
• the bath does not shrink and is immediately ready for use,
• the cost of the foundation for the bath is minimized due to the ease of construction,
• walls made of OSB panels with 150 mm thick insulation do not freeze in winter and provide quick heating of the interior space, retaining heat for a long time.
• and finally, OSB-panel is the ideal pre-finished panel for any interior and exterior decoration.

The service life of a panel bath depends on quality characteristics domestic finishing materials and averages 25-30 years. In operation, a panel bath is no different from baths made of other materials.

Conclusion: what material to build a bath from

Materials for building a bath, such as brick, foam concrete and sandwich panels have their advantages, but they are artificial. best material for a bath - natural wood and he should be given preference in the construction of a bath. You can build from wood at any time of the year, whether Cold winter or dry summer. The tree serves as an excellent heat insulator, as it has an excellent ability to accumulate heat and keep it for a long time, which is important when heating a bath. The baths, built from rounded logs, combine the old Russian traditions of construction. wooden buildings and modern production technologies, which makes them unsurpassedly beautiful.

From a civil engineer's point of view, with a special heat and humidity regime. Therefore, in comparison with conventional "dry" buildings, the requirements for materials are increased here. Materials for construction are selected according to performance. This:

• thermal conductivity- it is largely "responsible" for the rate of heating;
• strength- not the main criterion for a one-story building, but it must also withstand with a solid layer of March snow, and this is several tons;
• durability- largely depends on the first two qualities, however, such an object should be enough for several decades.
• density And porosity b. In many ways, these are closely related concepts. Since it experiences a powerful steam and heat “attack” at least once a week, its walls must be vapor permeable.

can be built from wood, brick, various types of cellular blocks (foam concrete and gas silicate). And with the advent of modern high-quality heat, steam and waterproofing materials baths began to be built according to the mixed, so-called frame technology .

In addition, the choice of the technology used is influenced by the traditions of the "bath business" of a particular region, and simply the availability of certain building materials. So, in Karelia, it would never occur to anyone to “cut down” from anything other than wood, and in the steppe regions of the Russian Federation they will prefer high-quality brick. This is where we start the review.

Brick version of the bath

First of all, let us clarify that for construction it is possible to apply only red ceramic fired brick. White silicate easily absorbs moisture and is not recommended for "pair procedures". And although no one doubts its strength and durability, however, it will take a long time to warm up such a structure.

The main disadvantage of a brick bath- high heat loss due to high thermal conductivity. To reduce it and at the same time create a relaxing heat and moisture atmosphere, you should clad the walls from the inside reflective vapor barrier(for example, with one-sided foil foam), and additionally upholster on top of it.

The most important and indisputable plus brick - high fire safety. Agree that for a building that is being heated, this is an important factor.

block variant

You can often find cinder block baths(not to be confused with cellular blocks!), Having good thermal performance. However, slags themselves are concentrators of heavy metals that cause direct harm to human health. In general, cinder blocks should be considered only as a forced stage in the development of the building materials industry, which in the 50s became a response to a sharp lack of quality. Now is a different time, and it is unacceptable to use such blocks for the construction of residential premises and baths.

They came to replace vibropressed blocks made from concrete mix. An excellent building material in terms of strength and ease of installation, but it has one drawback - poor thermal protection, requiring additional. Therefore, the next step in the “bloc” direction was the use cellular blocks which have high thermal resistance.

Cell Blocks There are foam concrete and aerated concrete. Moreover, the second is much better than the first. Them Benefits - durability and non-flammability. But the walls of them should also be lined from the inside with the same materials as the brick ones. Of course, such blocks do not burn and do not support fire.

Bath frame

Frame technology, which occupied a significant segment in cottage construction, is also trying to penetrate the bath "market". The essence of the frame is well-thought-out and conscientiously laid in wall structure A "pie" of layers of vapor barrier, and waterproofing (if listed from the inside of the house to the outside). Outside and inside, such a wall should be lined with finishing panels.

The thermotechnical highlight of the technology is that the material must be kept dry. Otherwise, it completely loses its insulating properties. And if in an ordinary living room the vapor barrier successfully copes with such a task, then in the conditions of regular heat and humidity "attacks" it will not be easy for him to resist them for a long time. Somewhere, yes, there is a crack, hot wet steam will penetrate into the body of mineral wool (100-150 mm thick) and disable the thermal insulation. Therefore, the modern technology of the "frame" has not yet found wide application in the bath business.

Wood is different

In Russia, it is customary to build from wood - the most environmentally friendly material. Due to the ability of wood to pass air well, rooms from it independently regulate humidity. Wood has low thermal conductivity and retains heat for a long time, which is especially important in.

However, there are spots in the sun, and wood has flaws. wood like natural natural product, rotten. Therefore, wooden ones are less durable compared to the same brick ones, for example. The main "eaters" of wood are constant rains, aggressive insects and, unfortunately,. However, against all these troubles, applied science has already come up with its own “antidotes”. Some special chemical compounds will protect against spider bugs, and others will protect against fire.

Important: do not follow aggressive advertising and hope that one universal composition protect from everything. According to experts in the field of household chemicals, you should not use compositions with a catchy name such as "all in one". For fire protection, get one special solution, and against bugs - another.

What types of wood do you prefer?

Aerobatics in bathing is considered swamp spruce, dried up on the vine. But is there a lot of it and where to find it?

Traditionally used dry and. IN different regions our vast homeland, their preferences based on the predominant type of local wood. So, for example, in Primorsky Krai baths are made from or from. Yes, they put a log in such a way that its northern side, which is denser by definition, is outside. The trick is small, but it must also be taken into account.

One more detail - the presence of resin in rocks. On the one hand, it favors the bathing process. But not everyone will be pleased to feel it literally on themselves. To once and for all exclude resin from the bath space, experts advise soak thoroughly for at least a day. In this case, the resin will evaporate completely from all the sinuses.

Also used for indoor cladding board: resin is absent in it initially.

Design choice

Having decided on the types of wood, we move on to the structures. Here can be used either traditional or planed.

If we talk about preferences, then in the minds of our people there still lives an image

Bath ventilation is divided into general exchange and conservation. We call the drying of the bathhouse after water procedures a conservation ventilation. 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 shower rooms is carried out by aerodynamic methods - dry ventilation air enters the zone of moistened materials, evaporating water. Water vapor enters the air. Across exhaust ventilation Humidified air is removed and fresh air enters. In this way, technological process drying involves several stages and is far from simple.

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

Moisturize - dry

With all its advantages, wood 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 subject to all three types of biological destruction - due to bacteria, fungi and insects, and dry wood only due to insects. If the wood rot is slimy with an unpleasant odor, this is most likely bacterial rot. If plaques, colors (spots 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 suburban individual baths, which will stand for many years even with colors. But for representative and apartment baths, micromycetes are the number one scourge, as they spoil the appearance of the finish. But the most dangerous for baths are macromycetes - large, real mushrooms with characteristic fruit caps, living directly on wood (like mushrooms, tinder fungi, sponges). Many summer residents, surprised to notice brown fan-shaped mushroom caps sticking out of the floor in their bathhouse, best case they will only scrape them off and smear the place of growth with vitriol or hrompek, not realizing that these hats are just the fruiting bodies of a house wood-destroying fungus. The fungus itself is hidden in the floor, walls, foundation (both in wood and brick) in the form of a system of branching threads (single GIF - cords up to 1 cm in diameter), forming a mycelium several meters in size, so that the only way to stop the development of the fungus is antiseptic treatment large areas. The normal temperature for the development of house mushrooms is 8 - 37 ° C, the relative humidity of wood is 25 - 70%. IN 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 house fungus stops at a relative humidity of wood of the order of 18% and below. Considering the wood hygroscopicity curves from this point of view, several conclusions can be drawn. Firstly, to maintain wood moisture content of 18% or less at all temperatures of fungi development (5-40°C), relative air humidity of no more than 80% is required. Otherwise, even absolutely dry (but not treated with water-repellent compounds) wood will be moistened above this level by itself (without contact with room water) by absorbing moisture from the air. So in tropical countries there are more problems with wood than in the north. Secondly, considering the wood hygroscopicity curves in other coordinates (Fig. 1), it can be noted that wood, arbitrarily strongly moistened at a temperature of 30 ° C and absolute air humidity above 0.03 kg / m3 (that is, at the calculated relative humidity air 100% and higher relative to the wood temperature), dries at a temperature of 40°C to a moisture content of 11% (and only up to 11%!), and at a temperature of 80°C to a moisture content of 2.5% (and only up to 2.5%! ). All this is extremely unusual: non-porous materials in these conditions would dry out completely. 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, we recall how dry wood is moistened. If you splash water on wooden board, it is gradually absorbed into the depths of the wood: first into the intercellular spaces (vessels, pores between the fibers), then into the thick (dried) cell cavities, then into the cell walls. All these pores are wettable capillaries. Due to the formation of concave menisci of water surfaces, the pressure of saturated vapor over water inside the wood is less than over water spilled over the surface. Therefore, not only water, moving along wettable surfaces, but also its vapors rush into capillaries (intercellular and cellular), moisten (and then dry quickly). The 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 "dry"-looking board without water drops 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 the bath, it is also used to create a condensation climate regime in the Russian steam bath, when due to the high relative humidity of the air near the ceiling (for example, when water is applied to hot stones), the ceiling (preferably a massive log) is first moistened. Then, in the periods between feedings, a high absolute humidity is created near the ceiling - above 0.05 kg/m3. metal ceiling under these conditions, it would not just “drip” without retaining moisture in itself, it could only create a quite definite relative humidity of air at its surface, equal to 100%. A wooden ceiling (like any porous one) can, in principle, create only a well-defined relative humidity of air near its surface, and at a fixed moisture content of wood (due to the massiveness of the walls, for example), the relative humidity of the air not only near the ceiling, but also in the room can be maintained also almost constant regardless of how the room temperature changes. The effect of stabilizing the relative humidity of the air in wooden residential buildings(in brick and plastered ones too) are 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 bath and a wooden bath, even with the same steam generator, give different climatic conditions. Indeed, 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 humidity of 0.01 kg/m3). In accordance with fig. 1 relative humidity of wood under these conditions is 12%. Now let's hypothetically heat up this sauna (without ventilation and without humidification) to a temperature of 70°C. The bold dotted horizontal arrow in fig. 1 shows that the absolute humidity in the sauna jumps up to 0.14 kg/m3, it's time to take a steam bath with a broom! Where did the water come from! The wood began to dry and moistened the air. By the way, it is the water vapor coming out of the wood that “pulls” the “wood smells” that are so valued 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 steamy. And if the sauna is ventilated during heating fresh air the same absolute humidity of 0.01 kg / m3, then the air in the bath will remain dry, and the moisture content of the wood in the bath will decrease and sooner or later will drop to 1% (see the vertical bold dotted arrow in Fig. 1), that is, as they say in everyday life, the boards will “cry out”. And then, after the end of the bathing procedure, they will again be moistened due to the sorption of air moisture to a humidity of 12%. In the language of meteorologists, "wood tries to keep (maintain) a constant relative humidity of the air." Indeed, in the above wooden bath wood "kept" the relative humidity in the bath at 60%, which can be achieved under conditions of rising temperatures only by moistening the air with wood. Nothing like this can happen in a plastic bath: when it is heated, the absolute humidity of the air remains constant, and the relative humidity drops. It is the glass sheet metal and plastic are ideal materials for dry physiotherapy and apartment saunas. And if you use wood, then only thin, specially treated to prevent hygroscopic absorption of moisture from the air. The decorative craze wood trim bath (not always justified) leads to the fact that even bath hygrometers are sometimes performed in wooden cases(!), “Keeping” the relative humidity inside them constant, regardless of the temperature and the true humidity of the air in the bath. By the way, we recall that the measuring thread of the hygrometer, located inside the case, stretches when moistened (like an ordinary woolen thread) and thus 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 elongated mainly only when the relative humidity of the air changes. This is the basis of the principle of operation of natural filament hygrometers. 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 sanded and dried bifurcating wooden branch are well known. A thick mustache (the main branch about 1 cm thick) is cut 10 cm above and below the fork and nailed vertically to the wall (baths, houses, cellars). A thin mustache (a shoot about 0.3 cm thick and 0.5 m long) goes up parallel to the wall. In dry weather, a long thin branch leans, moves away from a thick one (“bulges out” with an increase in the acute angle of the fork), and if it rains, it approaches the thick one. If there is a certified industrial hygrometer, then this home-made hygrometer can be calibrated with marks on the wall opposite the location of the tip of a thin mustache at various relative air humidity. The principle of operation of such a hygrometer is that when dried, 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 of wood occur 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 wood, then free water in large capillaries of intercellular and intracellular spaces, then water in small capillaries of cell walls. The latter, as we have established above, determines the hygroscopic moisture content of wood, which exists and changes even in a dry unheated bath. Therefore, the drying of cell walls can actually be controlled in the greenhouse conditions of dry built-in saunas, although bound water can in principle support the processes of wood decay, especially, as we noted, in warm and humid climatic conditions.

The phased drying process is also characteristic of other porous materials, including bricks, plasters and soils (earth). Their drying is also important for the bath, if they are part of it. In this regard, let us recall the fundamental, although only indirectly related 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 vise, then it will retain the shape given to it (for example, arcs), and the better, the better the wood dries. Under 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 stone high-temperature 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 under conditions high temperatures, irreversible changes occur in the cell walls, and wood actually ceases to be wood and begins to exhibit the properties of an inanimate material. Similarly, clay soaked in water, during drying and heat treatment, first loses its plasticity, then cracks, and then becomes a brick, which subsequently does not change its shape and properties upon contact with water. Particularly good results are achieved during the primary drying of wood with superheated water vapor, and also by immersion in a hot anhydrous coolant (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 membranes of the cell walls (and they, in fact, are wood - a combination of cellulose, lignin and hemicelluloses). During subsequent drying, the wood dries faster and behaves like “lifeless” because the cell walls have already torn. However, dry wood as a porous material has specific features, which distinguish it from other materials, in particular, the anisotropy of properties, secondary warping, etc.

Drying dynamics

Water spilled on the surface of wood evaporates in the same way as water poured into a bath 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) of 539 cal./g, fly out from the surface of compact (liquid) water and are irretrievably removed. The kinetic regime is realized during evaporation in vacuum. Due to the high rate of the primary act of vaporization (escape of water molecules from the surface of compact water), which at bath temperatures is thousands of kilograms of water per hour from 1 m2, there is a strong cooling of water (since only slow molecules remain in it) until it turns into ice, which is used in freeze drying industry. In the diffusion mode, the primary act of vaporization remains the same and just as strongly depends on temperature. But the ejected 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 surface of the water, experiencing strong resistance from the air. As a result, the vast majority of the ejected molecules “fly” into the water again (condense). Thus, in the diffusion mode, tons of water turn into steam and immediately condense (which we do not feel at all), and only a very small amount of water (kilograms) completely evaporates. It is this diffusion mode of evaporation that takes place in the 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 is equal everywhere in the bath (including near the surface of the human body), then no evaporation processes are possible (homothermal regime). But at the same time, it becomes clear that if tons of water per hour evaporate and condense simultaneously in the bath, then we can assume that this should someday manifest itself. 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 those water vapor molecules that previously condensed are removed by the air flow. For orientation, we indicate 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 velocity in the room is always much greater than directly above the water surface, and any quantitative indicators are extremely indicative. For estimates, one can use experimental formulas for basins. In any case, the characteristic speed of drying floors in baths 0.1-1 mm/hour (0.1-1 kg/m2/hour) increases with increasing floor temperature and decreasing air temperature (that is, with decreasing absolute air humidity). So, for example, in open pools at a constant water temperature, evaporation is maximum not at all during the day, but at night in cold air, as well as in winter. In the daytime, in hot weather, evaporation can stop, and even water vapor can condense from the air onto the surface of the pool, just like water condenses on human skin in a condensation-type steam bath in a mode above homeothermal. 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 water vapor condensation, summing up the above-mentioned evaporation and condensation processes on the water surface. Let's call it conditionally condensation. In the language of condensation curves, drying is as follows. On fig. 2 shows the condensation curves for the floor at 20°C (curve 1) and for the ceiling of the steam bath at 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 a given temperature. Thus, if the air in the bath has a temperature of 40 ° C and a relative humidity of 6096 (and it does not matter whether the air in the bath is still, 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 either the air temperature or its relative humidity, or better both, is reduced so that the air characteristics are below curve 1, for example, if the mode corresponding to point 4 is realized. The fact of possible air movement (blowing the floor) does not change the qualitative picture, but only affects the rate of evaporation or condensation. By the way, it is this mechanism that works in case of catastrophic moistening of the undergrounds of a residential building, to which a bathhouse with leaking floors is attached. Warm wet air from drained to the ground hot water spreads over long distances and emits condensate on cold subfloors and the foundation of the entire residential building.

The main conclusion is that conservation ventilation is not just a change of air in the room of a damp bath. It is necessary to supply air with as low a temperature and relative humidity as possible, more specifically with as low an absolute humidity as possible. 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 necessary to heat not the air, but the floor of the bath, for example, with infrared radiation. And if, nevertheless, it is possible to warm up only the air, then it must be dried, as is done in washing and dishwashers. Note that the sometimes recommended methods of drying the bath with the release of hot moist air through the floor into the underground lead only to additional moistening of the cold (and therefore the most problematic) elements of the bath. It is better to release hot moist air through the upper vents, in which condensation is not possible. In fact, in almost all baths for conservative drying of the interior, general exchange ventilation is used.

With 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 walls of the pores are not wetted by water, which means that the pressure of water vapor in the pores is greater than on the surface of the wood. This leads to "evaporation" of water from the pores to the surface of the wood in the form of droplets, which then evaporate again as described above.

Water that fills pores with wetted walls, including unimpregnated wood, evaporates in the 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 actual 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 greatly affect the drying rate. The "blowing" of materials is characterized by a parameter called vapor permeability, equal, for example, for mineral wool 8 - 17, for pine along the fibers - 10, pine across the fibers - 2, brick - 2, concrete - 1 in units of 10 "6 kg / m / sec/atm Thus, with characteristic static pressure drops due to wind of 104 atm, the actual values ​​of the drying rates of porous materials 10 cm thick 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 super-diffusion materials (perforated membranes ) The drying rate increases with the 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 humidity and the time of year, but the temperature of the internal elements of the bath has a much greater influence. It would be possible to continue the analysis of wood drying issues and consider the most reasonable solutions for conservation ventilation. But it makes no sense to deceive: the centuries-old experience of operating wooden baths shows that no matter how dry the wooden floors are, there are still no guarantees of the quality of drying, they still rot. Indeed, if 1 m2 of a wooden floor absorbs conditionally 1 kg of water, then drying it at a rate of 20 g/m2 will last 50 days. Therefore, wood is covered with roofs and awnings wherever possible (and not only in baths), but even in this case it is able to moisten. condensate 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 safety of unheated areas wooden structures. Air ducts smaller than 1-3 mm, on the contrary, are stagnant, poorly ventilated areas, the moisture from them evaporates slowly, which creates conditions for rapid decay, especially when in contact with vapor-tight materials, and even more so with constantly moistened ones. The question is not about how to properly dry the wood, but about how to generally remove it from the bath 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 foam concrete floors and then makes incredible efforts to dry it. So rusting steel is painted, and they do not try to quickly dry it after every rain. IN modern baths all wood that may 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 coatings, as well as shelters, not to mention antiseptic and fire-fighting treatment. Wood in a bath is a problematic material, and the prevailing opinion that a 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 a greenhouse environment of an apartment corridor, untreated wood is acceptable even on the floors, but even there it is only in the form of a removable drying grate.

CEILING VAPOR PROOF

Methodically more difficult is the question of ventilation of the wood of the upper parts of the walls and ceiling. The task of conservation ventilation here, too, is to supply dry air to moistened zones 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 ventilation air.

The ceiling (or rather, the ceiling) can be moistened by precipitation during emergency roof leaks and during steam condensation. Previously, moisture was predominant due to trivial leaks, since until the 19th century in cities and until the 20th century in villages there were no bath roofs, except for wooden (tes, slit-shingles), straw and reed roofs. log walls and ceilings in the event of a roof malfunction could absorb hundreds of liters of water in the rain. 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 accidentally arose, then the walls and ceiling had to be dried sooner or later, but be sure to dry. This was achieved by constantly ventilating the attic space, organizing where possible vents, gaps and cracks in log and plank structures, that is, the same techniques were used as in the natural drying of firewood in logs, but, of course, while maintaining the heat-insulating ability of 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 the most dangerous. So what happened, as a result of which everyone around began to talk about the indispensable need for vapor barrier of the walls and ceilings of the bath as the most important thing? Indeed, for centuries in log black, and then in white steam baths, they did not know about any vapor barrier, and steam moistening is so insignificant compared to leaks that they cannot create a dangerous level of wood moisture content above 18 percent for a long time (especially in dry built-in saunas ).

We note right away that the question of vapor protection of wood and insulation first arose in baths in connection with the appearance in everyday life of soft waterproofing roofing materials(used, moreover, often not for its intended purpose), and dangerous levels of wood moisture have become exclusively local and long-term. However, before moving on to this issue, consider common features moistening wood with condensing steam.

Usually, in the literature, the moistening process is described briefly and simply: moist 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 vapor condensation occurs and the wood is moistened only at this point. In fact, the process is more complex. Firstly, wood is a wettable porous material, so the released condensate is absorbed by the wood and is distributed along the wetted pore walls over a large volume of wood (blotter effect). By the way, 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 finely porous (for example, like mineral wool, which practically does not have capillaries) or if the material is treated internally with a water-repellent preparation and is not wetted, then the wood moisture curve is transformed 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, there is a constant condensation of moisture from the air in the same way as described above. However, if the inner surfaces of the porous material are not wetted, the released condensate cannot be distributed over large volumes of walls (that is, it cannot be absorbed) and inevitably accumulates in separate zones, forming droplets as well. When using mineral wool, drops of condensate flow down in streams on the lower elements of building structures, for example, on wooden beams, logs, crowns, strongly moistening them. In any case, in vapor-permeable (breathable) walls, it is desirable to make ventilation ducts (air ducts) 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 wood (boards, clapboard, siding) inside and out so that the gap between the boards and logs plays the role of steam channels (ventilating facade).

Needless to say, there has always been a desire to prevent water from entering the walls at all.

So, in particular, in stone (brick) city baths, the walls remained moist for years, despite ventilation. Therefore, the internal 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 material 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 a roof covering, 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, wood-fiber boards, wood concrete, sectional straw wetted 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 non-leaking, or to upholster the plank walls of the bath from the outside with roofing material to protect against wind and rain. As a result, the shavings, which were previously moistened only with rare leaks, and when moistened under the influence of steam penetrating from the bath, immediately dried out, under a layer of roofing material lost the ability to dry out after any moistening. More precisely, shavings under the roofing material can dry out only when moisture is removed back into 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 rolled materials, called windproof, were developed for these purposes. They do not let compact water (raindrops) through due to non-wetting and at the same time slightly let air with water vapor due to porosity or perforation, but protect against gusts of wind. It should be noted that gusts of wind create pressure drops up to 10 "atm., which exceed pressure drops due to heating the air in the bath 10 5 atm. is passed in a very limited amount. The fact is that the gas-dynamic resistance of the windproof material is much less than the gas-dynamic resistance of the protected wall made 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 of an easily blown insulation , then here the 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 moisture. Indeed, by covering the chips on the ceiling with windproof material, we will only be sure that an accidental leak of the roof will not moisten the chips, and if it does get wet (in any way), it will dry out sooner or later anyway. But if the temperature of the wind protection layer is below the dew point, then moisture will condense on this layer, which cannot pass through the wind protection in a liquid state. 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 barrier 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 lay a vapor barrier in areas with a temperature above the dew point. If the vapor barrier is made in the form of wall cladding (plastic, steel, ceramic), then there are usually no questions about its installation. But what if the vapor barrier film is laid inside the walls? For example, is it necessary to make a gap between aluminum foil and decorative lining? The answer is simple: if there can be compact water, 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 the steam bath after several years of operation, you will see that where there was no water (in the center of the ceiling), the back (upper) 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 for them to dry out when the roof leaks. Therefore, having prevented the penetration of steam, it is still desirable to restore the possibility of blowing the wall through the organization of air vents on the outside, and preferably on the inside of the vapor barrier, although the role of the conservation ventilation of the inside can be assumed by the general exchange ventilation of the room. At the same time, the supply and exhaust openings of the vents should go outside or the premises adjacent to the bath (dressing room, vestibule). To assess the required dimensions of the vents, consider a log bath with a volume of 10 m3 and an area of ​​enclosing structures of 25 m2. The degree of emergency humidification will be taken 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 drying time of the walls can be achieved at a wall ventilation rate of 1 m3 / h, which is significantly lower than the ventilation rates of the bath rooms - 10 m3 / h or more. Such a speed can be provided by air supply and exhaust openings between logs and vapor barrier, with a 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 design of construction, including multi-storey buildings, implies the development of insulating materials for highly specialized functions and only sometimes combined functions. So, for example, waterproofing, windproofing, vapor barrier, heat-insulating 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 walls and which, playing the role of air vents, could remove moisture from hard-to-reach most critical places in any form (in the form of compact water or in the form of steam). It is these drainage materials that will apparently become the basis of progressive solutions for the conservation ventilation of walls in the future. Indeed, how to dry (or keep dry) the massive brick walls that have been in a wet state for years, the walls of urban public baths, laundries, and swimming pools? Neither elevated bath temperatures nor maintaining a relative humidity of 40 to 60 percent in laundries and swimming pools can keep walls completely dry, even if they are protected by ceramic tiles. Recently, hollow building materials (slotted bricks and concrete blocks with cavities, foam materials) have become widely used, but these voids in the walls must somehow be interconnected and connected to centralized supply and exhaust devices that regulate the speed of conservation ventilation within the required limits. This role will be assumed by new ventilating materials, primarily in ventilated facades and roofs.

One way or another, using ultra-modern or traditional materials and designs, 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 the problematic parts of the walls (especially load-bearing structures) and are ventilated exclusively with external air under the action of wind pressure. With a large size of air ducts, it is desirable to close the ventilation ducts to local supply and exhaust openings, the flow sections of which, if necessary, can be adjusted. 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 moistening of the walls with humid bath air.