Materials for the construction of a bath: selection of the constituent supporting structures. Saunas from a kiln-dried bar Baths from a kiln-dried bar

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 which materials are best used for building a bath.

What material is the bathhouse made of:

rounded logs;
timber;
brick;
concrete;
various types of panels.

The best material for a bath - Log walls

Most often, baths are built from wood. Particular attention is paid to the strength and quality of the material: any irregularities or loose spots can cause tangible heat loss.

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

Aesthetics. For many, when choosing between a squared log building, aesthetics are one of the main factors.
Environmental friendliness. Wood is an environmentally friendly material, absolutely safe for humans.
Low thermal conductivity. Long-term preservation of heat is provided due to the low thermal conductivity of wood compared to other materials (brick, concrete, panel). There is no need for additional thermal insulation.
Durability. By this criterion, timber baths are significantly superior to panel and frame buildings. Longevity depends on many factors - from the choice, harvesting and storage of wood, and ending with the maintenance of the building. Subject to the technology of building a bath, proper and timely care, such a bath will last quite a long time. The estimated period, subject to all standards, 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 a brick bath. Basically, conifers are used for the construction of baths - pine, larch. Pine is distinguished by a small number of knots and the largest straight trunk. Larch is denser than pine and more resistant to decay, resistant to moisture, 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 construction standards. To increase fire resistance, wood is impregnated with fire retardants, the choice of which is huge.

Building material for a bath - Bar

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

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

Brick walls for the construction of a bath

Building a good bathhouse out of brick and stone is more difficult than building it out of wood. However, in some cases, when brick and stone are more accessible than wood, you have to build from them not only the foundation, but also the walls. Using brick during construction, you can maintain a high temperature in the room during the day, but such material will take much longer to warm up. A brick bath is more durable and less fire hazardous. Its main drawback is large heat losses due to high thermal conductivity. To reduce it, it is recommended to sheathe the bath from the inside with clapboard, placing a thick layer of steam and thermal insulation between it and the brick wall. Any brickwork absorbs and allows moisture to pass through, so the contact of the walls with the ground is not allowed.

Moisture-resistant materials for a bath include:

moisture-resistant drywall, used in the interior decoration of the bath and requires the application of an additional primer;
moisture resistant panels.

Concrete walls for a bath

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 execution, otherwise it is better not to use foam concrete.

When performing masonry work from a foam block, you must remember about the additional waterproofing of the material. It can be bituminous soil (liquid bitumen) with preliminary treatment with deeply impregnated soil.

In the panel construction of the bath, the external walls are 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 construction. Due to the lightness of the walls being erected, it will be enough for a panel bath

Currently, the Canadian technology for the construction of country houses from OSB sandwich panels is gaining more and more popularity. It is possible to build a bath from this material, 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 lightness of the structure,
walls made of OSB - panels with 150 mm thick insulation do not freeze in winter and provide quick heating of the interior space, keeping heat for a long time.
and finally, OSB - panel is the ideal roughing panel for any interior and exterior decoration.

The service life of a panel bath depends on the quality characteristics of interior 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 own advantages, but they are artificial. The best material for a bath is natural wood and should be preferred when building a bath. You can build from wood at any time of the year, be it cold winters or dry summers. Wood serves as an excellent heat insulator, as it has an excellent property of accumulating heat and retaining it for a long time, which is important when heating a bath. The baths, built of rounded logs, combine the old Russian traditions of erecting wooden buildings and modern production technologies, which makes them unsurpassedly beautiful.

Talking about the health benefits of a bath is a stupid business. And so each of our compatriots knows perfectly well that regular trips to the bathhouse allow you to remove toxins and salts from the body, stimulate metabolism, increase immunity and simply improve well-being.

Interesting interior of the bath

But if you want the bath to really give you maximum pleasure, it must be built according to all the rules. The most important of these is the correct choice of building material. So what is the best way to build a bathhouse? It is worth giving the most detailed and detailed answer to this question.

The modern market for construction products is quite rich: wood, reinforced concrete, frame construction, and so on. However, not all of this assortment is suitable if you want to build a bathhouse. Moreover, most of the materials listed above are completely unsuitable for construction.

The only material that can be called a really good choice is wood. In this case, you can use wood of different species: some are better for building a bath, while others are slightly worse.

An example of a bath made of wood

But in any case, it is worth changing the tree to some other material only as a last resort. For example, if a log or timber is too expensive or difficult to obtain material in your area. Then you can build a bath from expanded clay concrete blocks, bricks or foam blocks, but the steam room itself will definitely need to be sheathed with wooden boards. And it is worth taking such a step only if there is no alternative to such construction, and you really want to get a bath.

Fortunately, in most regions of our country, wood is not only affordable, but also a very cheap building material, therefore it is best.

Large volumes of harvesting together with a huge stock of knowledge on the correct preparation of wood make the construction of baths as easy as possible.

You can buy a ready-made kit for building a bath, order the construction of a turnkey bath, and if you have certain skills, build a bath with your own hands by purchasing the required amount of prepared timber or timber.

But still, before starting construction, it is worth finding out which tree is best to build a bath from. In general, when building, you can use a variety of types of wood, but still some are much better suited than others. And it's worth knowing about it in order to make the right choice.

We build from softwood

Today it is coniferous wood that is most often used in the construction of baths. There are many reasons for this. Firstly, thanks to natural resin impregnation, these types of wood are less susceptible to decay, which is very important for a bath: high humidity and temperature can have the most negative effect on the material.

Secondly, in the steam room, decorated with coniferous wood, there is always a special aroma that will appeal to any connoisseur of the bath. Finally, some coniferous logs are the cheapest, and therefore the most affordable, which remains one of the most important factors when choosing a building material.

So, what kind of conifers can serve as a source of wood for the construction of a bath? There are several of them:

Spruce. One of the most common and popular building materials. The low weight combined with the softness of the wood makes the processing as easy as possible. This has a positive effect on the cost of building material: almost everyone, if they wish, can save up the required amount to build their own spruce bath. It is also important that for many years of operation the spruce retains its original golden-white color. Alas, this option has one drawback - a high resin content. Of course, this gives a definite advantage: the wood practically does not rot even after prolonged and intensive use. However, at high temperatures, resin is released from the pores of the wood, which can cause serious problems when visiting a bath. Therefore, during the construction of a spruce bath, experts recommend to carry out internal cladding using wood of other species.
Spruce wood example
Even when working in difficult conditions (high humidity), the wood is practically not susceptible to the appearance of mold or mildew. This is due to the fact that it contains a natural antiseptic. Thanks to him, the bathhouse, during the construction of which larch was used, has a tonic and curative effect. A regular visit to the bath can prevent the onset and development of diseases of the cardiovascular system. The high hardness and high weight make the processing of larch an extremely difficult process, which affects the final cost of the building material. A larch bath will cost you about 2 times more than a bath made of spruce, pine and other cheap wood species. Well, on the other hand, you can be sure that this bath will serve you, and your children, and your grandchildren.

How to build a sauna professionally and competently.

Every owner wants to have a bathhouse on his personal plot, therefore these household structures are often erected before the completion of the construction of the main house. 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 rain shower, many homeowners prefer to build a free-standing bathhouse equipped with a stove, steam baths, and sometimes supplement it next to located pool.

When implementing these plans, the owner of the site, first of all, is faced with the following questions: what material for the construction of the 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 premises.

What materials are used to build a bath

When deciding on the construction of a bath, it must be remembered that it is a rather complex engineering structure that requires compliance with rather stringent measures to ensure safety during operation. At the same time, the question of which material is better for building a bath is, to a certain extent, rather prosaic. No room for washing and receiving bath procedures can be built from one material. Additional building and finishing materials will be required for pouring the foundation, heat and vapor insulation, and roofing.

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

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

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

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

Some gardeners and summer residents boast that they managed to build a bath from scrap materials.

Paying tribute to the low cost of such construction, it should be noted right away 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 on the Internet.

It is generally accepted that the best material for the construction of a bath is wood, which can be used for the construction of walls, the arrangement of floors, ceilings and for the manufacture of elements of rafter and roof structures.

Features of wooden baths

When choosing a finishing material, the greatest attention is paid to the products intended for the cladding of the steam room and the washing department. There should be no knots in the carriage board, because with several heating-cooling and wet-drying cycles, these knots will surely fall out, giving the wall panels an unaesthetic look.

The most widespread for interior decoration was lining made of linden, alder, aspen and maple.

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 changing rooms, there are no special requirements for finishing materials. Here you can use any lining or edged, grooved board, afterwards treating it with stain, soaking it with linseed oil and varnishing it.

The greatest difficulty in the construction of a bath is the choice of material for 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 the floors, one should not only choose the highest quality materials, but also when laying them, it is necessary to provide for all measures to ensure high-quality hydro-steam-thermal insulation.

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

For Russia, the bath is considered a place where you can not only spend time. It has long been known: in order to cleanse the spirit and body, you need to thoroughly steam with a birch or oak broom. But the question arises of how to efficiently and economically build at least a mini-bath on your site.

In this article, we will explain how to do this, what are the best materials to choose, how much does it cost... Let's consider the main mistakes of construction, time and financial aspects.

What is important at the beginning?

Having decided to build, one should understand a small but significant thing. Nice little bathhouse needs a project. Many people underestimate the importance of drawings and calculations. And speed, reliability, comfort and cost depend on it.

Advice! Before going to the architect, you need to decide on the material.

Log walls

It so happened in Russia that wooden baths were erected. There are reasons for this. The following breeds are usually chosen:

Pine.
Fir.
Cedar.

The log bath will not rot, moisture resistant. No additional vapor barrier required.

Pros:

Natural material, environmentally friendly.
Keeps warm well.
"Log" ones are considered to be the most durable. In terms of quality, they are superior to frame, stone - buildings. Observing construction technologies, the service life without repair reaches 70–80 years.
Relatively inexpensive material, it all depends on the region.
Excellent aesthetic appearance.

Minuses:

The disadvantage of this material is the obligatory subsidence of the building by 15–20 cm. After the construction of the frame, it is recommended to wait a year.

Erection from a bar

Most often, timber is used in the construction of baths. It exists of four types:

Planed.
Glued.
Not planed.
Profiled.

It is possible to use any of the listed materials. But the most popular is considered to be profiled or planed. Let's consider each separately.

Planed

The special treatment makes it practically invulnerable to cracking. The timber that has passed the chamber drying will be more expensive. It all depends on the professionalism of the builders. For example, if you build it yourself, then it is advisable to choose high-quality processing.

Install well from a prepared timber. This is easier thanks to the "comb", which provides an easy, reliable and tight grip. That allows construction to be carried out with less effort.

Mezhventsovye areas are protected thanks to a special profile. This also allows you to do without repairs for many years, to preserve the heat of the walls.

Advantages:

Long service life.
Environmentally friendly material.
Low cost.
Easy to assemble.

Disadvantages:

Violations in the drying technique lead to deformation, twisting.
It is "susceptible" to crackling even with processing.
May darken over time.

Glued

More "difficult" to manufacture. Made from planks and logs. High-quality drying and gluing. Due to the processing of two or more lamellas, it is considered the best material for the construction and decoration of baths and saunas. It is chosen by people who are not used to saving.

Pros:

Allows to erect a building in a month or two.
"Gorgeous" aesthetically.
Practically not subject to shrinkage.
Does not deform.
Due to its high-quality processing, it does not crack.
Optimum humidity excludes the appearance of fungus and mold.

Minuses:

Expensive material.
The use of adhesives makes it not environmentally friendly.
It is very quick to assemble a panel bath, which is used by commercial enterprises.

Not planed

The most inexpensive and demanded of materials. Not planed timber (sawn timber) is a square or rectangular section. The production is carried out from spruce or pine. Drying of wood takes place not in chambers, but in the fresh air. This made it possible to significantly reduce the cost of the material.

Pros:

Minimum costs for the construction of the frame.
It can be used as a finishing material.
Doesn't require highly qualified specialists.

Minuses:

After the box has been erected, the building is left to shrink for a year.
It is necessary to additionally insulate, seal the cracks. Cracks may appear during use of the building.
External insulation is required.
Needs additional interior decoration.

Profiled

It got its name from the connecting locks. From can be divided into the following:

Comb.
With one thorn.
With two thorns.
Norwegian.
Finnish.

Easy to install. Slots and mezhventsovye corners are gouged at the construction site. The most suitable type of material.

Advantages:

High-quality grinding allows you to use it in decoration.
Do not use harmful chemicals.
Made from spruce, pine, oak.
Due to its low thermal conductivity, it retains heat well.
A low proportion of shrinkage - 4–5 cm.
Fast erection with small forces.

Disadvantages:

Poor drying will lead to more sinking.
It is necessary to treat yourself with fire-fighting agents.
After construction, there will be no possibility of redevelopment.

Nowadays, a barrel-bath made of profiled material is very popular. The price starts from 60 thousand for an already assembled structure, which can be conveniently accommodated even in the smallest dacha plot of six acres. Moreover, the structure is being commissioned. without foundation.

Modern building materials for a bath

Few people know that baths built with bricks and cement will look and function as well as wooden ones. Consider the common options from expanded clay blocks (cinder block) and bricks.

Brick bath

Stone structures have a number of advantages over wooden structures. The advantages include:

resistance to weather conditions,
practicality,
the possibility of redevelopment.

But the cost will rise significantly - this is due to the preparation and installation of the foundation. And also the obligatory interior decoration.

For the construction of brick baths, the services of professional builders of various specialties are required. If only carpenters are needed for wood, then here you will need:

Bricklayers.
Plasterers.
Finishers.
Roofers.

Building quickly on your own will require tremendous knowledge and experience. Incorrect wall laying will lead to the formation of condensation and instability of the structure. You will also need additional thermal insulation of the building facade.

Foam block

This material is more suitable for construction. Although it is considered a "young" material. He had his own fans. They are successfully used in the construction of residential buildings, including baths from foam blocks.

Light weight, excellent thermal conductivity allows you to make a warm building. But just like a brick, a foam block needs a foundation and additional thermal insulation. The main qualities of the stone are its fire resistance. For example: a brick crumbles under the influence of high temperature. This cannot be said about.

It is made from sustainable materials. Easy to handle. The low price allows you to compete with other building materials.

The most expensive materials in construction

Frequent mistakes in construction

In order for the bath to turn out to be of good quality, it is necessary to pay attention to the mistakes that are made by both professionals and amateurs:

The tree should be dense from conifers: spruce, pine.
Incorrectly calculated foundation.
Logs should be from 20 to 25 cm. Too thin will fit only for a village "makeshift", will lead to loss of heat.
To preserve heat, it is necessary to use moisture-resistant wood in the decoration; alder, poplar or aspen can handle this.

Due consideration should be given to oven bricks... First, it must be red fireproof. Secondly, one-piece, you can not use hollow. A window that is too large or too small is considered an error. For a bath, it should be at least 50 * 50.

Which is better - to build it yourself or to use the services of a company?

Building a bath brings with it a number of problems. This is a dilemma: build independently or through a firm. Choosing independent construction, you need to be ready for such processes as:

Responsibility for quality.
It takes a lot of effort and time.
Building experience is needed.
You can forget about the quick completion of construction.
Hire assistants (shabashniki).
Purchase, delivery - materials.
Foundation calculation.

Of course, there are pluses in self-construction. Namely:

Freedom of choice.
Phased construction.
Better control.
Savings in money.

The firm's advantages and disadvantages:

Hiring a company removes a number of problems with finding workers.
The responsibility for quality lies with the firm.
Assumes the development of the project and supervision of the construction process.
The construction will be done by professionals.
Fast completion of the project. You can even order a project of a bathhouse with a swimming pool.

Cons:

additional financial costs.

Obviously, hiring a company that can carry out turnkey construction is much more profitable than doing such a complex business alone.

Cost overview

Summary table. The prices for various materials are indicated along with the work:

How to build a budget bath with your own hands: let's go through the main steps

The first step is to decide on the materials and placement, area. And you will also have to face such obstacles as:

calculation and laying of the foundation,
frame erection,
finishing,
will determine the insulation,
vapor barrier,
think over the installation of equipment.

Foundation

To make the base strong and economical, the pile option is suitable for its construction. It is much easier to make than tape.
The next step is markup. Don't forget about partitions indoors.
Then the location of the piles is noted. The distance between them should wash two meters. The piles must be at the intersection of the walls and at every corner.
Wells should be 25-30 cm wide and 1-1.5 meters deep.
The well is half filled with sand, spilled with water, followed by compaction.
After that, you can start immersing the asbestos pipes. Around them, a reinforcing and wooden frame is created for pouring concrete.
Leave such a structure to dry completely - for five days.

Caracas

You will need a well-dried timber.
Before installation, it should be treated with an anti-corrosion compound.
At intersections and corners - reinforced beams are installed (vertically).
Each such pillar should stand every meter from each other, not forgetting to leave openings for the windows.
The whole structure is united by bars, or boards, and fastened with jumpers from a bar.
A frame with a roof is assembled in such an unpretentious manner.

Finishing - insulation

OSB plates are used in the decoration.
Sheets are screwed with wood screws.
The gaps of the joints are filled with polyurethane foam.
Inside, the decoration takes place according to the same principle with only one difference: insulation and vapor barrier are inserted before stitching.

Completion

After sheathing and insulation, you can start arranging furniture and additional equipment.

Important! Furniture should be made of moisture resistant wood. Purchased electric ovens can be used as ovens.

Outcomes

It is building on our own that is a long, nervous and seasonal process. The fastest way to assemble a bathhouse on the site is from foam concrete or a ready-made dried log house. If you work in four or more hands, then one season will be enough for the construction of the foundation, walls and roof. Well, the external and internal components of the cladding are a secondary issue.

The optimal combination according to the conditional "Price-quality" characteristic concerns:

Dry log buildings (medium diameter);
Baths made of red brick (subject to normal interior decoration). Resistant to fire;
Premises made of timber 15 X 15, 20 X 20, preferably dry.

Advice! When planning the purchase, plan and time of year for construction, do not rush to calculate the area. A 4 x 4 meter log house or masonry is enough for a whole family, where even a washroom can fit.

For your information, barrel-baths do not count, because it is a prefabricated structure, a kind of temporary option for several years.

The best video about building a bath with your own hands

Sergey Zhornachuk's material has deservedly gained more than 200 thousand views, thousands of likes and approving comments. An excellently edited, informative, sensible video about the construction of a bath with his own hand.

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, gets overdried, 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 a specific bath process, the characteristics of wood, its possible morbidity and 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 the 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 smear 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 GIF - 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 down 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 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 deep into the wood: first into the intercellular spaces (vessels, pores between the 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 the 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 out) 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 during drying in the form of water vapor and can humidify the air. This effect is used not only when drying a bath, it is also used to create a condensation climate 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 create only a very definite relative humidity of 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 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's 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 vapor coming out of the wood that “pulls” the “smells of wood,” 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 during heating is ventilated 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 dotted 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 wood bath discussed above, the wood "kept" the relative humidity in the bath at the level of 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, and 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 moistened (like an ordinary woolen thread) and thereby shows how much it is moistened. 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 sharp 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 various 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 bathhouse 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 noted, in warm and humid climatic conditions.

The step-by-step drying process is typical for other porous materials, including bricks, plaster and soils (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 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 membranes of the cell walls (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 mode, the fastest molecules, overcoming the 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 escape 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 emitted 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 regime). 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 homothermal. 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 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 mechanism that works in case of catastrophic humidification of the subfields of a residential building, to which a bathhouse with leaking floors is attached. The warm, humid air from the hot water discharged to the ground spreads over long distances and produces condensation on the cold sub-floors 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, almost all baths use general ventilation 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 conservation 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 the quality of drying, 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 other hand, airs less than 1-3 mm in size are stagnant, poorly ventilated zones, moisture evaporates from them slowly, which creates conditions for rapid decay, especially when in contact with vapor-proof 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. In the same way, 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-prevention treatment. 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 conservation 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 in the event of a malfunction of the roof 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 happened by accident, then the walls and ceiling had to be dried sooner or later, but be sure to dry. 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 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 earlier, in black logs, and then in white steam baths, they did not know about any vapor barrier, and steam humidification is so insignificant compared to 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 insulation 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: 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 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 along the wetting 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, 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 the stone (brick) city baths, the walls remained moist for years, despite the ventilation. Therefore, the inner surfaces of the walls, wherever possible, were protected with 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 of this, 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 wind gusts. It should be noted that gusts of wind create pressure drops of 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, having covered 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 vapor 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 there can be compact water 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 steam from entering 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 leaks. 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 better, on the inner side of the vapor barrier, although the general ventilation of the room can assume 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 bathhouse (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 design, 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 conservation 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.