Wood for building a house: how dangerous high humidity. Natural wood humidity - it is important to know! Wood transport humidity how many percent

Freshly wood has a natural humidity. But this does not mean that the moisture of all the wood is about the same.

Not at all the same humidity will have pine, growing on a dry place and tree, cut in a swamp. Humidity can be even higher, for example, when when weaving along the river, the tree has gained moisture as much as it could. If you make a board from such wood, without drying it in advance, then the boards, of course, will turn out, but over time they will definitely disappear and quit. As a result, it will have to teeling the sheaving boards kicked to the wall - to sort out the trim. And even if it is for the upholstery to use lining with an eurorophile, the cracks will still appear in the trim, which will be the greater, the greater the width of the cladding used. The truth of the gaps themselves will be less. (The wider lining, the less cracks, but they themselves more. And vice versa - the smaller the slit, but more than their quantity.) And this is if she is dry material for raw. If the material of the base is raw, and the trimmed raw, then the consequences will be even worse and sad. This is just one of the options for throwing money "to the wind".

The tree during the sweetener loses from 5 to 7% of its sizes in width and thickness, and only up to 1% in length. This means that if this year you folded the log of 3 meters high, then in a year its height may well be on 10, or even 20 centimeters less. But in length and width, it will remain almost the same as it was.

It is for this reason that most construction companies suggests their customers in the first year to fold the house from the bar and only next year to produce his finish.

That all this did not happen, it is necessary to dry wood to dry.

That is why GOST is determined by the moisture of wood used. So for the inner covering, wood should be applied with humidity up to 15%, for outdoor - up to 20%. The humidity of the geepar also should not exceed 15% humidity.

There are several ways to determine the moisture content of wood. In domestic conditions, use a special electrolygizer instrument. The effect of the device is based on the change in the electrical conductivity of the wood, depending on its humidity. The electrical magometric needles with the supplied electric drives are injected into the wood and pass through them the electric current, while on the scale of the device immediately marks the moisture of wood in the place where needles are introduced. Many experienced cutters determine the moisture content of the tree. Knowing the types of wood, its density and other physical sv-va, it is possible to determine the moisture content of wood by weight, by the presence of cracks on the end or along the fibers of the wood, for warning and other features. In the color of the cortex, its size and color of wood, you can recognize ripe or freshly edged wood and the degree of its moisture.

On the ability to absorb moisture affects not only the microclimate of the room, but also the tree of wood. The most hygroscopic rocks include beech, pear, Kempas. They most quickly react to changes in the humidity level. Unlike them there are stable breeds, for example, Oak, Merbau, etc. These include bamboo stem, very resistant to adverse climatic conditions. It can be flattened even in the bathroom. Various wood species have different levels of humidity. For example, birch, grab, maple, ash has low humidity (up to 15%) and when drying, have a tendency to form cracks. Oak and nut moisture and mild (up to 20%). They are relatively resistant to the formation of cracks and dry out not so quickly. Olha is one of the most resistant to drying rocks. Her humidity is 30%.

Humidity - One of the main characteristics of the wood. Under the moisture content of wood understands expressed in percentage of the mass of water to the dry mass of wood.

Absolute moisture of wood The ratio of the mass of moisture is called in this volume of wood, to the mass of absolutely dry wood. According to GOST, the absolute moisture content of the parquet should be 9% (+/- 3%).

Relative moisture of wood - This is the ratio of the mass of moisture contained in the wood, to the mass of wood in a wet state.

There are two forms of water in the wood - associated and free. Of them there is a total amount of moisture in the wood. The bound (or hygroscopic) moisture is contained in the cell walls of wood, and the free occupies the age of cells and intercellular spaces. Free water is easily removed than the associated, and to a lesser extent affects the properties of wood.

According to the degrees of moisture, wood is distinguished by the following types:

Wet wood. Her humidity is more than 100%. This is only possible that the wood has been in water for a long time.
Fresed. Its humidity ranges from 50 to 100%.
Air dry. Such wood is usually stored for a long time in the air. Its moisture can be 15-20%, depending on the climatic conditions and the season.
Room and dry wood. Its humidity is usually 8-10%.
Absolutely dry. Her humidity is 0%.

Wood properties directly determine the properties of wooden products. With excessive or insufficient moisture, wood usually absorbs or giving moisture, accordingly increasing or decreasing in volume. With high humidity in the room, wood can swell, and with a lack of moisture, it tends to dry out, so all wooden products, including floor coverings, require careful care. To prevent the deformation of the floor covering in the room, it is necessary to maintain a constant temperature and humidity. This favorably affects not only the quality and durability of floor coverings and wooden furniture, but also on the health of people. With a sharp change in the temperature-humid regime in the room in the wood there are internal stresses, which lead in cracks and deformations. The optimal temperature in the room with parquet flooring should be approximately 20 degrees Celsius, and the optimal air humidity is 40-60%. Hydrometers are used to monitor the temperature in the room, and the relative humidity in the room is maintained using air humidifiers.

Wood properties also depend on seasonal changes in the microclimate of the room.

In the heating period, lasting since October to April, the temperature in the room rises, and the humidity decreases. The moisture level in the floor drops below the permissible level of 25%. Such differentials negatively affect the overall state of wood. Parquet strips vary in size, breathed, seams between them can diverge and form small gaps. Cracks can form on the coating. It is possible to eliminate such consequences by reducing the temperature and increase the humidity in the room.

In the summer, parquet absorbs more moisture. Relative humidity can reach 60%. During this period, the return process takes place: with excessive moisture content, the plank will burst, find one to another, their edges rise, and the coating is deformed. In this case, in order to restore the coating, it is necessary to regularly air the room or use the air conditioner and turn on the heating in order to reduce the humidity.

The deformation of rivets when changing the season can be very significant. With a change in the relative humidity of the air to 30% in winter to 60% in summer at a temperature of 20 per equilibrium moisture, wood can change by 5%.

Control the humidity and temperature regime in the room can be using a thermohydrometer. This will help in a timely manner and avoid deformation of the coating. The room temperature can be changed using air conditioning. To increase humidity, you can put open containers with water (for this purpose, aquariums, fountains, etc.) are excellent, or acquire special air humidifiers with built-in microclimate analyzers.

Air humidifiers without significant electricity costs will create a favorable climate in the room, ensuring the proper level of humidity. There are various types of air humidifiers (steam, ultrasound), depending on the method of evaporation of water.

For parquet floors and wooden furniture, ultrasound or traditional humidifiers are ideal. They protect wooden coatings and furniture from cracks and drying wood.

Drying wood

Dry wood has high strength, it is less breeding, not exposed to shockting, it is easily glued, it is better off, more durable. Any wood of various breeds very sensitively responds to a change in environmental humidity. This property is one of the shortcomings of timber. With high humidity, wood easily absorbs water and swells, and in heated premises it dries and brends. The room is sufficient to the moisture of wood to 10%, and in the open sky - no more than 18%.

There are many ways of drying wood. The easiest and affordable is the natural type of drying - atmospheric, air. It is necessary to dry wood in the shade, under a canopy and in draft. When drying on the sun, the outer surface of the wood is quickly heated, and the inner remains raw. Due to the voltage difference, cracks are formed, the tree is quickly brewed.

Boards, timber and other p / m fit into the stacks on metal, wooden or other stands with a height of at least 50 cm. The boards are stacked by internal layers up to reduce their stacks.

It is believed that the drying of the boards put on the edges occurs faster, as they are better ventilated and the moisture evaporates more intensively, but they are more and more, especially the material of high humidity. The pile of p / m, prepared from freshly edged and alive trees, is recommended from above to seal heavy load to reduce the charge.

With the natural drying on the ends, cracks are always formed, to prevent their cracking and preservation of P / m, the ends of the boards are recommended to thoroughly paint the oil paint or soak hot oil or bitumen to protect the wood. Processing ends need to be immediately after transverse fuse. If the tree is characterized by high humidity, then the end is dried with a flame of a soldering lamp, and then painted.

The trunks (ridges) are deficatory (purified from the crust), only the ends are left for small rigs-clutch 20-25 cm width to prevent cracking. Corre is cleaned so that the tree be sinking faster and is not amazed with beetles. The trunk left in the cortex, in relative warmth with high humidity quickly, is amazed by fungal diseases. After atmospheric drying with warm weather, the moisture of wood is 12-18%.

There are several other ways of drying wood.

Warming method

Or wrying used in Russia for a long time. The blanks are cut into parts, taking into account the size of the future product, lay in the ordinary cast iron, the sawdusts of the same workpiece are poured, poured with water and put for several hours into the drowned and cooled Russian furnace "languishing" at T \u003d 60-70C. At the same time, leaching occurs - evaporation of wood; Natural juices come out of the workpiece, the tree is painted, acquiring warm dense chocolate color, with a pronounced natural pattern of texture. Such a workpiece is easier to be processed, and after graduation, drying is less cracking and brewed.
Parafining method

The blanks are lowered into the melted paraffin and put in the oven at T \u003d 40C for several hours. Then the wood enhances the same for a few more days and acquires the same properties as after the rebel: it does not crack, does not breed, the surface becomes tinted with a distinct pattern of the texture.
Welding method in linseed oil

The dishes made of wood, stealing in flaxseed, is very waterproof and is not lightering even in everyday use. This method is acceptable today. The billet is put in the container, poured with linseed oil and steamed on slow heat.

Wood is a rather porous material containing a large amount of capillary filled with moisture. In practice, the moisture of wood is defined as the ratio of the weight of the water contained in the tree to the weight of absolutely dry wood. There is the concept of "free" and "bound" moisture. "Free" moisture is contained in the pores and capillary of the tree. "Related" moisture that is contained directly in wood cells.

When drying, the tree gives a destruction - decreases in the amount (volume). At the same time, the size decreases along the fibers (along the length of the board) is practically not occurring, but in the direction, the transverse move of the fibers, there is a significant change in the size (in the thickness and width of the board). The magnitude of this change depends on the wood breed and the specific value of changing the moisture content of wood. In the life, the most unpleasant surprises are associated with changing the width of the board.

For example, if you make a floor with a natural humidity board, then a decrease in its width over time can be so significant that two neighboring boards lose the engagement with each other. In this case, to remove the cracks, you will have to tear off all the boards from the lag and to be reinstalled, to intoxicate.

"What kind of humidity should there be a board?", - You ask. Everything is simple - any wooden product, in the process of its operation, seeks to the so-called "equilibrium moisture." "Equilibrium humidity" is determined by the temperature and humidity of the air in the environment where the board will be. The values \u200b\u200bof this humidity you can see in the table. For residential premises, it averages 8-10%, for the street it averages 12-14%. It is logical from this that the crude board will be inserted in the room, losing in its width, on the other hand, the dry board will be moisturized outdoors, expanding.

Natural humidity, finite wood moisture

Natural humidity - This is humidity inherent in wood in a growing or just cut (sawn) condition, without additional drying. Natural humidity is not normalized and can be from 30% to 80%. Natural wood moisture fluidity varies depending on the conditions of growth and season. So, the natural humidity of fresh trees in the "Winter" Forest traditionally less humidity of fresh trees in the "summer" forest.

Initial humidity - The same as natural humidity. Only a fired tree has a maximum humidity, which for different breeds may even exceed 100%. Balz tree may have moisture in a freshly powerful state that gives up to 600%. In practice, we are dealing with less values \u200b\u200b(30-70%), because After logging, some time passes until the cutting of the tree and placing it in the dryer and it, of course, loses some amount of water. We accept for the initial humidity, the value of the moisture of wood, which it has before shipping into the drying chamber.

Finite humidity - This is the humidity that we want to get after the complete drying cycle. In this case, the appointment of the product is made from dried wood is taken into account.

First of all, wood drying is the process of removing moisture from wood by evaporation.

Wood drying is one of the most important operations in the process of wood processing. Wood dried after sawmill, but in front of woodworking. The wood is dried in order to protect it with the lesion by wood-painting and wood-cutting mushrooms during its further storage and transportation. Drying warns wood from changing shape and sizes in the process of manufacturing and operating products from it, improves wood finishing, gluing. The humidity to which the wood is dried depends on the sphere of its further use. The whole point is reduced to bring the humidity of the board to the same meaning that would have achieved the product from this board during operation in these conditions. Such a moisture value is called "equilibrium humidity", it depends on the humidity and temperature of the ambient air. For example, a board from which the parquet and other outline will be made, operated indoors - should have a humidity of 6-8% as this humidity will be equilibrium. For products that will be operated in contact with the atmosphere, (for example: wooden windows, the outer covering of the house) of the equilibrium humidity will be 11-12%.

You ask: "What will happen otherwise?" We answer: otherwise, it will be what is found in Russia completely and nearby, namely the consumer will face problems. Imagine that you bought the wall paneling in order to sew walls inside your country house or giving. If you buy a lining with a raw board with a raw board and tighten the walls of your home, it will begin to slowly dry out naturally in the already established state. Turn to the table of equilibrium humidity and experience. If you natope in the winter room up to 25 degrees Celsius, then with a standard air humidity inside indoors in 35%, the value of equilibrium humidity for the board in such a room will be 6.6%. At bases and markets, the lining can very often have moisture from 14% and higher (we met and 30%). Next, imagine that your lining begins to dry, losing water from my pores. The hike is a process called "dry" and expressed in a decrease in the size of a wooden product. The value of the heatheus depends on the wood breed, the direction of fibers in the product, etc. The main sweep is across the fibers (respectively, the thickness and width of your clapboard). When your lining will dry in the prescribed state to an equilibrium moisture, you, at the most worst case, you risk not just to see that the skin has diverged, and get the slots between the boards, almost a finger.

In industry, various wood drying technologies are used, differing in both the equipment used and the peculiarities of heat transmission drying material.
The classification of species and drying methods is usually based on heat transfer methods for which four wood drying technologies can be distinguished:

convective drying technology;
conductive drying technology;
radiation technology drying;
electrical drying technology;

Each type of drying can also have several varieties depending on the type of drying agent and features of the equipment used for wood drying. There are also combined wood drying technologies, in which various types of heat transfer (for example, convective dielectric) are used at the same time, or other signs of various wood drying technologies are combined.

Independent drying technologies

Chamber drying

Chamber drying. This is the main industrial wood drying technology, carried out in the forest-drying chambers of various designs where lumber is loaded with stacks. The drying occurs in the gaseous medium (air, flue gases, overheated pair), which by convection transmits heat heat. For heating and circulating the drying agent, the drying chambers are supplied with heating and circulating devices.

In the chamber technology of drying wood, the timer drying deadlines are relatively small (from tens of hours to several days), wood enhances any given ultimate humidity with the required capacity, the drying process is amenable to reliable regulation.

Atmospheric drying

The second on the meaning and distribution in sawmills the method of industrial wood drying, carried out in the stacks placed on a special open territory (warehouses) washed by atmospheric air without heating. Advantage of atmospheric technology drying wood-relatively low cost. In addition, this method is the most gentle. Disadvantages: seasonality (winter drying is almost stopped); big duration; High end humidity. The atmospheric wood drying technology is used mainly for drying lumber in sawmills to transport humidity and on some woodworking enterprises for drying and aligning the initial moisture content of lumber before drying in drying chambers for wood.

Drying in liquids

Drying in liquids is carried out in baths filled with hydrophobic liquid (petrolatum, butter) heated to 105-120 ° C. Intensive transmission of heat from fluid to wood allows to reduce drying period compared to chamber 3-4 times, with other things being equal. This method is used in wood canning technology to reduce its humidity before impregnation. Attempts to apply the drying of sawn timber in petrolatum at woodworking enterprises did not give positive results due to the fact that lumber after such a drying do not meet the requirements for wood for furniture and joinery and construction products.

Conductive drying technology

Conductive (contact) wood drying technology is carried out by means of heat transfer with thermal conductivity when contact with heated surfaces. It is used in small volumes for drying, thin wood materials - veneer, plywood.

Radiation drying

The radiation drying of the tree occurs when heat is transmitted with radiation from heated bodies. The efficiency of radiation drying is determined by the density of the flow of infrared rays and their permeability in solid wet bodies. The intensity of the flow of radiant energy is weakened as depicted into the material. Wood belongs to infrared materials lowered for infrared radiation (the depth of penetration is 3-7 mm), so this method does not apply for drying of sawn timber. It can be used for drying thin-sheet materials (veneer, plywood), in addition, this method is widely used in wood finishing technologies for drying paintworks. Electric stoves, electric heating elements, gas (flameless) burners, incandescent lighting electrollamps from 500 W and higher are used as emitters.

Rotary drying

Rotary drying of wood is based on the use of the centrifugal effect, due to which the free moisture is removed from the wood when it rotates on centrifuges. Mechanical removal of free moisture is achieved with a value of centripetal, acceleration of at least 100-500g (G - acceleration of free fall). Such accelerations due to the difficulty of accurate balancing centrifuges with a stack in practice have not yet been achieved, only experienced developing appropriate devices are underway. In well-known industrial rotary dryers, the centripetal acceleration does not exceed 12G. Under these conditions, mechanical dehydration is manifested to a small extent. However, the intensification of the drying process in the humidity range above the hygroscopicity limit is observed.

When installing the carousel in the drying chamber, the drying technology of sawn timber is the same as in conventional periodic chambers. Duration of drying at the first stage (from initial humidity to the limit of hygroscopicity) is reduced several times depending on the thickness, rock and initial moisture content of wood compared with the usual convective dryer with the same modes. Although rotary dryers are economical and provide high quality drying, industrial use for drying lumber rotary method has not yet found.

Vacuum drying

Vacuum drying under reduced pressure in special hermetic drying chambers. Due to the complexity of the equipment and the impossibility of obtaining a low ultimate moisture of wood, a vacuum drying of an independent value has no value. It is used in combination with other drying methods and as an auxiliary operation in the preparation of wood to impregnation.

Dielectric drying

Dielectric drying is a drying of wood in an electromagnetic field of high frequency currents, in which wood heating occurs due to dielectric losses. Due to the uniform heating of wood throughout it, the occurrence of a positive gradient of temperatures and overpressure inside its duration of the dielectric drying is ten times less convective. Due to the complexity of equipment, a large electricity consumption and not enough high quality drying, the dielectric drying actually does not find a wide application.

Combined wood drying technologies

The use of combined wood drying technologies is more efficient, such as convective dielectric and vacuum-dielectric. For mass drying, the use of these methods is not economically, but in some cases, especially when drying, expensive, responsible lumber and billets made of hardwood breeds, these methods can be used.

Convective dielectric drying

With a combined convection-dielectric technology, wood drying to a stack loaded into the chamber, equipped with thermal and fan devices, also apply high-frequency energy from a special TVH generator through electrodes located near the stack.
The consumption of heat on the drying in the drying chamber is mainly compensated by the thermal energy of the steam supplied to the calorifers, and high-frequency energy is supplied to create a positive temperature difference over the material cross section. This drop, depending on the characteristic of the material and the rigidity of the specified mode is 2-5 ° C. The quality of the convective-dielectric drying of lumber is high, as the drying is conducted with a small difference in the thickness of the material.

Vacuum-dielectric drying

This is another way of drying wood using TWH energy with this technology use advantages and vacuum and dielectric drying. Due to the heating of wood in the TWH field under reduced pressure, boiling water in the wood is achieved at low temperatures of wood, which helps to preserve its quality. Move moisture in wood with vacuum - dielectric wood drying is provided by all major driving forces of moisture transfer: a gradient of moisture content, temperature, overpressure, which reduces the duration of the drying.

With a vacuum - dielectric dryer, the lumber stack is placed in an autoclave or hermetic chamber, where the vacuum pump is created by a reduced medium pressure (1-20 kPa). The lower the pressure of the medium, the lower and the evaporation temperature of moisture and wood during drying. Consumption of heat drying is provided by the high-frequency energy to the wood. When using this technology, drying wood also occur operational difficulties - the complexity of the equipment, especially the commissioning and operation of high-frequency generators, the high flow of electricity to drying. Therefore, in solving questions about the use of vacuum - dielectric cameras, it is necessary to develop a feasibility study at the terms of a particular enterprise.

Induction, or electromagnetic wood drying

The method is based on the transfer of heat material from ferromagnetic elements (steel grids) laid in a stack between rows of boards. Stacking together with these elements is located in an alternating electromagnetic field of industrial frequency (50 Hz) formed by a solenoid mounted inside the drying chamber. Steel elements (grids) are heated in the electromagnetic field, transmitting heat and air heat and air. In this case, a combined heat transfer material is happening: conductive from the contact of heated meshes with wood and convection from circulating air heated as well as grids.

A tree is a living plant that naturally absorbs water to maintain vital activity. Spinal recently, it contains a significant percentage of humidity, in different breeds it is individual. Nevertheless, this value must be considered when buying a material to understand, wood is suitable for further processing and use or still needed.

Views of humidity

Absolute - the ratio of the mass of the liquid in the volume of wood to the mass of the dry sample of the same size.

Relative shows the amount of moisture relative to the mass of the same tree sample in the same condition.

In natural material, adjoin the associated and free moisture:

Free is in the intercellular space and makes up the artery of the tree. This is easily removed during drying and does not affect the quality of the workpiece;
Related is contained in wood cells.

Norma

Wood breed moisture content regulation regulatory documents:

SNIP II-25-80;
SP 64.133330.2011;
GOST 16483.7-71 *;
GOST 17231-78.

There are moisture norms for wood by material use class. For each individual breed, it is difficult to determine the amount: in what conditions the plant grew, which season was issued, in which the land was produced - all factors are displayed on the amount of moisture in one individual. Average meanings:

Wood moisture content: the norm according to GOS is defined for ready-made structures in different operating conditions.

Definition of humidity

To determine how many percent of the natural moisture of wood should be used by one of the methods:

The easiest and most common is the use of a water meter - an electrical device whose work is based on measuring the electrical conductivity of the measured raw materials. Three needle electrodes are inserted into the wood, the device allows a discharge on them and displays the desired value to the screen.
Probe with four needles to work with chips are based on the same principle of work.

How to determine wood moisture without moisture meter

The accurate calculation with the measurement error is not more than 1% describes GOST 17231-78. Simplified algorithm:

Take the cut of wood weigh it.
The sample is placed in the drying chamber with air temperature + 103 ° C to obtain a constant mass.
The dried cut is cooled to room temperature and weighed again.
Determine the moisture content of the formula:
- W \u003d (M-M0) / M0 * 100%, where M and M0 are the mass of wood before and after drying.

Definition of devices can give an error to 10%:

Electrodes penetrate insignificant depth, water in the trunk or product is unevenly distributed. When dried, the upper layers become more dry.
Each breed breaks up in different ways with moisture.
Specific electrical resistance of different types of trees individually, universal devices are not taken into account.

The methods described by GOST methods and durable, the definition of the value may take several days and requires special equipment.

Experienced masters determine the humidity of the tree in appearance:

In the color of the breed;
By availability;
Boxing, etc.

Wood readiness for processing can be defined independently:

According to the quality of the bark: the wet tree has rich and soft, in the process of drying the crust harvested;
At the place of cutting: fresh plant is a wet-fuzzy;
On the chips: when compressing a beam, it should not stick up - this is not ready for processing, the product will give a significant shrinkage.
The presence of uniformly distributed shallow cracks speaks of the maturity of the material, deep - about drying and inhomogeneity.

In our opinion, the most controversial question in the Internet. Let's detail based on GOST answer this question. Also, based on experience and practical examples, let's try to figure out and give logical answers to all of the issues listed.

Wood moisture this is the ratio of the mass of moisture in the volume of wood, to the mass of absolutely dry wood.

Watering of lumber is measured by moisture meter.

A tree is a living material that grows, sleeps, breathes. Most indicators in the wood due to this change from year to year. And such an indicator as humidity in the wood, as well as the humidity of a dry lumber is changing even during the year. This indicator depends on the time of year, from the area, place of growth.

Two main indicators on which the natural moisture content of wood depends.

Also on the moisture of wood affects the region, the place of growth.

When wood comes less wet, it will dry faster, and the drying process is softer and breaks it less.

Dry lumber

Transport humidity and furniture humidityget by drying.

Wood humidity happens:

Natural humidity (40-60%)
Transport moisture (18 +/- 2%)
Furniture humidity (8 +/- 2%).

Wood moisture depends on the use of sawn timber.

Natural humidity 40-60% is used for formwork, in the rafter system, for crates, etc.
Wood furniture humidity 8 +/- 2% is used, the name already gives a prompt, first of all and most in the furniture production, as well as for the production of glued timber.
In all other cases, the transport humidity of 18 +/- 2% is used and used for any construction, for the production of sawn goods, such as block house, tongue, etc.

Sometimes the client comes and says: "I want a welfare of a bar of 8%."

Ask: "Why?"

Answer: "I was told (I read) it will be better."

Based on GOST 8486-86 and on experience, for construction, transport humidity is the most optimal humidity. Because with a humidity of 18 +/- 2%, the sawn timber does not cord, does not twist, it does not shine, not subject to fungal infection. Lumber of transport humidity fully justifies its physicomechanical characteristics in construction.

Also conviction that the bar can be dried up to 8% absolutely incorrectly, and no one has ever seen such a bar.A timing of drying less than 20% is impossible, yes the upper layers no one argue can be dried to a humidity of less than 20%, but the core? The humidity of the bar in the core reaches 20%, which corresponds to GOST and DIN. With this humidity, the bar and the board does not cord, does not twist, it does not shine, is not subject to fungal infection.

There are also interesting data that is entered in the table below.

Based on the data of the table, the equilibrium moisture content of wood is 17-18.5%, if proceeding from the average data (air humidity 80-85% and the temperature of +10 s). It is logical that, for the construction of a house from a bar, humidity is less than 20% simply not needed. The construction site from this will not "win."

You can, of course, hear the argument about the glued bar, it is dried to a humidity of 8%.

First, it is not dried by a bar, and lamellas (board).
Secondly, the manufacturers of glued timber lamellas need to be glued together so that they converge tightly and do not worry over time, did not dismiss.

In principle, hence the glued laminated bar of poor quality. He was poorly dried, because he dried the board, not to mention the timber, to the humidity of 8 +/- 2% not easy, did not bother, schitri and over time the bar may disappear, the lamellae disappear.

Customers also come, who say that we have demolished my grandmother's house, and we could not disassemble it. The roof "I moved", and the log house, as stood "inserted" and stood.

And the client with an exclamation summarizes: "They built!".

Of course, no one was chased to build, as quickly as possible, cheaper, no one chased for "new technologies." And the tree was spilled, ignorated, they gave the time a log to cure, and then only collected.

And how is it now? Everything is done with accuracy. The client wants faster and cheaper, the manufacturer gives, what is ready to pay the client. Here is a general result.

The desire to savely save, spoils the opinion about the best natural building material. The tree will repeat this living material, he "survives" only in the hands of professionals.

From the logs of which moisture can you create reliable and warm wooden chopped houses? Experts believe that for construction it is necessary to choose the material of only natural humidity. Why?

Secrets of an ancient wooden house-building, It says that a wooden chopped house must be built from the logs of natural humidity. And it is not surprising, because such a material has many advantages that can be justified from the point of view of modern data. Although I must say that the durability of the log houses built in the old days, which have been standing for several centuries, in itself is the proof of the rulite of the ancient masters. But still, why is the natural moisture of wood so important?

From the properties of the building material, In particular, now we are talking about wood, the strength characteristics of the house strongly depend. With an inequilibrium humidity, the tree takes or gives moisture, while its diameter changes. So, with a large moisture, the logs absorb water and increase in volume, and during dry air he dries off. If there is a sharp change in air humidity, stresses occur inside the logs that cause cracking and deformation. To avoid it is necessary in production (at all of its stages) to control the lumber humidity.

Distinguish such types of lumber:

Wet wood. Her humidity is almost one hundred percent. This turns out when the sawn timber spent a long time in water. Such material is never used in construction.
Wood natural humidity, recently fired. The humidity of such a sawn timber depends on the tree of the tree, the time of deforestation and ranges from fifty to eighty percent.
Air and dry lumber. This tree was kept for a long time on the street, his humidity ranges from fifteen to twenty percent.
Room and dry lumber. This tree, which has long been kept in stock, its humidity is from eight to ten percent.
Fully dry lumber. This tree after forced drying in special chambers, its humidity is no more than two percent.

Experts say that if the logs for the house set to subjected to a forced drying or for a long time to store in a sweaty form, then they can deform.

The tree loses its moisture until the humidity does not reach a certain level. Level depends on atmospheric conditions. The same process passes when absorbing (sorption) moisture.

If there is a completely dry lumber to take out to the street, Bring to the construction site, it will begin to absorb moisture from the air, which will be the cause of his swelling or curvature. Practice has shown that the house cut from dry wood does not give a uniform shrinkage.

Unlike the design of the logs of natural humidity, The loghouse from the forcibly dried log does not decrease in size (dries), but increases (swells). In this case, the walls are twisted outside, the crowns and roof can be dispersed. Remove the completely consequences of this process is not easy, expensive and often unreal. Even pine, which is considered a solid tree of wood, loses its strength to six percent, while its shock viscosity increases on average ten percent.

If the house kit is cut from the logs of natural humidity, Then the decrease in humidity in the tree is gradually. At the same time, the volume of the house decreases, under the influence of its own weight, the crowns are tightly falling into place. As a result of the dense fit, the logs are less blurred, and therefore it will also be necessary to spend less strength and finance for insulation.

With the construction of natural moisture structures It is impossible to make hard fixation. Approximately two years is the main shrinkage of the house design, which cannot be interfered. Shrinkage can range from three to seven percent - the size depends on the tree of wood and environmental conditions.

It is important to remember that the dewing and swelling of the sawn timber along and across the fibers comes at different speeds, Therefore, all vertical elements of the house must be equipped with compensators.

With the help of compensatory devices, you can adjust the height of the house and geometric proportions. For reliability, the crowns are attached to each other with the help of aging of wood, which are mounted in a checker manner after a half meters from each other.

Masters when they create wooden chopped at home, remember that the dermiska is an uneven process. It can go differently outside and inside the house.

Therefore, in the production of the house kit, technological gaps are made, which impede the incense dense fit in the groove, because it subsequently becomes the reason for the appearance of large gaps.

The secretions of the construction of log houses are many and only experienced masters can build a warm and reliable house, which will have a few centuries.