Cracks in logs. Dried timber: positive factors and necessary equipment Growth in the crack of the timber what to do

The durability of the structure depends on the quality of the drying of the wood, otherwise the timber may warp, rot over time, and insects and fungus will definitely start in it. So how to dry a timber without cracks and residual harmful moisture? After all, only proper drying improve the mechanical qualities of wood, prevent warping, decay and cracking.

Note that the instruction states: the moisture index indicates the amount of water in the wood. By the way, this moisture can be both free and bound. But free moisture evaporates well, lightening the wood, and bound moisture leaves very slowly.

Features of dried timber

It is clear that at first moisture from the outer layers intensively evaporates. This is what creates a lot of stress in the wood: stretching the surface and the appearance of cracks.

Varieties of timber

Experts specify how to dry timber with different shrinkage coefficient:

• low drying - pine, spruce, fir, white poplar, cedar;
• medium drying- beech, oak, aspen, elm, black poplar, ash, small-leaved linden;
• strongly shrinking- hornbeam, Norway maple, birch, larch.

Percentage = weight of water in wood/weight of dry wood.

Dried lumber properties

Let's summarize the goals of timber drying:

• increase the safety of the material;
• enhance strength properties;
• avoid cracks;
• strengthen connections;
• simplify construction work;
• increase insulating ability;
• protect the tree with paint immediately after installation;
• reduce the inevitable changes to the finished building;
• improve the surface without additional cladding.

Methods for creating dried timber

atmospheric, natural

• We store the beams in stacks under awnings on outdoors a few months.
• We will cover their ends with glue or lime to avoid cracks.
• But from changes in weather, humidity and temperature, the material is sometimes deformed, small cracks form.

Chamber

A highly effective alternative to the atmospheric method is chamber drying.

• Timber in drying chambers equipped with heating heaters, fans, air ducts favor uniform, proper drying.
• The effectiveness of such drying is indisputable: we do not depend on the weather, and the process is controlled by a computer, reducing time, but increasing volumes.

Note! Freshly cut it already with 20% humidity.

Generator

Drying with high-frequency generators.

• Here, the wood in the circuit of this generator is the dielectric in the capacitor ( Electric Energy submitted alternating current turns into heat).
• The bar, heating up, dries intensively and evenly.
• But the cost of electricity is significant, which means that the price of timber is higher. By the way, ready-made dry timber is always 2 times more expensive.

Types of drying chambers

convective

IN convection chambers energy comes to the wood from the air cycle, and heat transfer - by convection.

There are 2 types of such cameras.

• Channel dryers continuous action, where stacks are constantly pushed further to a drier place in 4 to 12 hours. The tunnel is loaded from the "wet" edge, and unloaded from the opposite, "dry" one.
• Drying chambers of special periodic action are smaller than tunnel ones and can have only 1 door. But the parameters of the environment, ventilation, ventilation reversal guarantee perfect drying. After the end of drying, the chamber is completely freed and loaded with raw logs, from this the energy loss increases by 20% than in tunnel chambers.

Condensing

• The condensation chamber collects the evaporating moisture on the coolers and drains it into the sewer.
• But here heat pumps do not give high temperatures, so the cycle is slowed down.
• Electricity is provided by the cooler compressor.

innovative

• Vacuum chambers with a pressure of 0.5 bar accelerate the drying of the timber with a complete absence of warpage and cracks.
• Microwave chambers, electromagnetic dryers are also innovations, as are hot air dryers.

Drying at home

High-quality drying of timber at home can be carried out in one of the following ways.

Natural drying

Advice! It is worth knowing the time of cutting a tree under a beam: in autumn and winter there is no movement of juice, which means that the humidity is minimal - the logs will dry out quickly.

Conditions for proper drying:

• Selection of material of the same thickness and breed.
• Straight stacked material: Straight stacks and trellises between rows will increase air circulation.
• Base pads.
• Pegs one under the other and intermediate boards in a row with pegs;
• Optimal air movement: loose placement so that air can flow horizontally.
• Air shutters for uniform ventilation of stacks.
• The canopy will protect from rain and sun, and the ventilated area of ​​the site will speed up the process.

Note! Prolonged drying of the timber drying timber at home guarantees humidity less than 18%.

Thermal chamber

• Imitation dryer: non-residential premises with brick oven and heating along the walls.
• We build stacks with our own hands, lay trellises in rows and heat the stove, raising the temperature to 50 degrees.
• Then the room cools down to + 20.
• Let's repeat the cycle.
• A week later, the beam is ready.

Advice! Final only in a heated room. Therefore, ventilated attics, heated sheds and garages, and residential buildings are the best storage and dryers.

Conclusion

• Primary drying is carried out in warm air, minimal humidity, but in natural conditions.
• We build the platform on poles.
• Across and along we put the timber on thin strips (for free ventilation).

It is not easy to find out the moisture level of the obtained dried wood at home. The master determines it by mass, by eye or by sound (dry wood rings when tapped).

Experienced practitioners recognize the degree of moisture from the chips: they tie a long chip in a knot. If the chips have not collapsed at the same time, then the wood is still damp, and if it breaks up, it is already dry. But let's pay attention to the core of the timber - it is sometimes more humid, then it is worth drying a little more.

The video in this article has additional information we need on this topic.

During operation wooden houses or baths, cracks begin to appear in the timber. This process cannot be prevented, as it is typical for wooden buildings.

Why, it is desirable to seal cracks in the timber

Small cracks on the surface of the wood do not negative impact for the operation of the building. Most often, they can be decorative element giving the logs a certain personality. Still, the appearance of cracks should not be treated negligently.

If cracks in timber have a width of more than 5 mm and spread throughout the log or beam, then it is necessary to take measures to prevent their spread. Why do it?

• Water will get inside the cracks, the moisture content of the wood will increase and it will begin to rot.
• Wood cracks are a favorite place for various bark beetles, which, feeding on wood, will render even the most durable logs unusable.

Therefore, if deep cracks are found, they must be repaired immediately.

Prevention of cracks

To prevent the appearance of cracks in the timber, it is necessary to apply a number of measures.

Sealing cracks in timber:

Preventive measures prevent the occurrence a large number cracks, but they cannot completely eliminate their formation. can hide cracks in timber, to prevent the processes of decay in them by embedding.

Sealing cracks in timber possible different ways. Of the materials most often used for this, putties that harden in air, dry mixes, and sealants.

Methods for sealing cracks in a beam

The above methods of sealing cracks can be used both outside and inside the house from a bar. All methods do not harm the wood, contribute to the removal of cold bridges and increase the strength of the tree.

Wood has been and remains the most popular material for building a house. This beautiful, eco-friendly, safe, fragrant, warm material perfect for all kinds of buildings. However, it also has disadvantages. No matter how diligently the owners take care of the house, cracks will still appear. So, how to avoid cracking timber in a wooden house?

What cracks are dangerous?

The danger lies not in the cracks themselves, which will appear sooner or later anyway, but in their depth. After all, if they reach the core of the timber used in the construction, this will not only significantly spoil appearance at home, but also significantly reduce the strength of the building. That's why experts recommend keeping an eye on the condition of your home, watching for cracking, and doing everything you can to keep the cracks from getting deeper.

Initial cause of cracks

Before you figure out how to avoid cracking a timber in a wooden house, you should find out why the timber is cracking. This happens for one very simple reason. The log dries unevenly, because it always takes more time to dry the middle than the upper layers, so during natural drying the log seems to dry out, but in fact the core remains raw. To prevent this from happening, it is better to purchase logs that are dried in special drying chambers.

What wood is better to take for construction

In order not to figure out how to avoid cracking the timber in a wooden house, immediately after construction, it is better to buy northern wood for construction, which was tarred before selling. It is resistant to the appearance of cracks, and if they appear, then only on the surface, without penetrating deeper. But if another wood has already been used, the house has been built, what should I do? Understand the causes of cracking and take action.

Causes of timber cracking in a finished house

To maintain the normal condition of the wood, measures must be taken to maintain a balance between the dry and wet layers of the timber. What can break it?

1. Spring sun. So that the tree does not crack in the spring, experts advise taking measures and protecting the house with special protective materials that will prevent moisture from evaporating from the tree.
2. Heat from furnace heating. Not only the sun, but also the usual stove can dry out the wood. But if the sun does it from the outside, then the furnace works from the inside. The first two years after construction, you should not heat the stove so that the timber does not crack.

How to protect wood?

So, how to avoid cracking timber in a wooden house? It is enough to follow some rules, and there will be much less cracks, and the ones that appear will not cause trouble.

• When choosing materials, you need to pay attention to the profile of the timber being sold and the compensation groove. If the latter is done correctly and extremely accurately, it is unlikely that it will ever be covered with cracks.
• From March to May, the house should be covered with UV protection products.
• During the construction and settlement of the house, the ends of the timber are treated with substances containing lime. The fact is that they do not allow moisture to evaporate and, therefore, the beam to dry out.
• For care wooden building you need the best stuff. Most suitable option- those that contain not only filters from ultraviolet radiation, but also linseed oil.

What if there are cracks?

Cracks that have appeared must be hastily repaired so that moisture does not evaporate through them, otherwise the beam will crack even more. Sealant, ordinary putty and caulk are suitable for closing. Paint is applied on top. If the cracks went inside the rooms, then they are covered with sawdust and plastered. But when large gaps appear, you will have to take a sealant.

Causes of cracks in the timber and ways to prevent their formation

1. Cracks in the timber are formed due to uneven shrinkage

Cracks in the bar occur due to the fact that the humidity inside the bar is higher than outside. Thus, the outer part of the bar "breaks", because. it rips her apart from the inside.

In the language of specialists and in the textbook, such defects in wood building materials are classified as follows: "Cracks are longitudinal ruptures of wood, formed under the action of internal stresses, reaching the tensile strength of wood across the grain...". Cracks in lumber are different, but in this article we discuss cracks shrinkage, the causes of their occurrence and ways to overcome their occurrence in the beam.

The humidity of the timber and its drying affect the quality of the building material wood. Drying can be atmospheric and chamber: in the first case, the beam dries out naturally, and in the second case, by force. The formation of cracks in the timber depends on how chamber drying is carried out, whether its technologies are followed.

Drying wood is accompanied by an uneven distribution of moisture in the body of the bar, which causes an uneven level of moisture in the wooden building material and leads to the formation of internal stress in it.

With atmospheric drying, the timber naturally reaches the required moisture content, being in a log house on shrinkage for up to six months. Thus, the drying process is delayed in time, but the internal stress in the wood is often balanced (or approaches its indicators) with the external one, because. In the natural environment, the humidity of the air is higher than in drying chamber, which smooths out the effect of wood bursting from the inside. Simply put, drying out from the inside, the timber is saturated with atmospheric moisture from the outside, which leads to a slowdown in the drying process, but at the same time, to a more gentle drying, a gradual balancing of the humidity outside and inside in accordance with the environment.

In order to speed up construction, developers sometimes resort to buying a log house from chamber-drying timber in order to get a house immediately without shrinkage, on a turnkey basis. Such construction is not only much more expensive, because. dry lumber is higher in price due to the cost of electricity for its production, but also leads to a poor-quality structure - some manufacturers of dry lumber violate the drying technology at high-speed drying.

It is not enough to simply place the raw material in the drying chamber and turn on high temperature. Special temperature conditions must be observed during the entire production of dry lumber, and at the end also connect the steam to prevent cracking of the wood from the outside, soften it so that the external layers are not torn by internal stress.

2. Compensation groove in the beam helps prevent cracking

One way to overcome the internal stress in the beam and, therefore, to minimize the formation of shrinkage cracks in the beam is the so-called. "compensation grooves" in the timber, which are sawn simultaneously with the manufacture of the wooden building material itself.

The relief cut relieves part of the internal stress in the bar, because. has the function of, as it were, artificial cracks - they are made in advance, before the real ones appear, but since they hide under the lower and upper crowns during the assembly of the log house, they become invisible and do not spoil general form buildings.

When a beam that has dried up from the outside bursts with tension from the still wet middle part from the inside, it either tears on the sides, forming cracks, or slightly opens in the compensation grooves. When the moisture leaves from the inside, it closes again and the bar takes on its original, albeit already shrunken, shape.

Visually, changes in the relief cut are difficult to notice and this does not affect mechanical properties wood and log quality.

The compensation groove is also made in the beam natural humidity, and dry. It helps to overcome the internal tension in the wood, regardless of how the moisture leaves it - naturally during shrinkage or forced in the drying chamber.

The presence of a relief cut in the beam does not guarantee the complete absence of cracks, but significantly reduces their formation: the softer and more natural process the release of moisture from the wood structure, the less the formation of deformations in it.

3. Other causes of cracks in the timber

Another reason for the formation of cracks in the timber is the sawing of the timber through the core of the log. In the case of sawing without a core, the beam does not shrink during shrinkage, and the formation of cracks is minimized.

It is possible to determine from which part of the log the timber was made from annual rings at the ends of the lumber: they are wider at the core, and narrow towards the edges. But this is often only possible for specialists and a simple layman does not pay attention to these details. Therefore, when choosing a building material, consider the beam not only from the sides, but also from the end.

So to build a beautiful and quality house from a bar, pay attention to the quality of the lumber from which your suburban building will be built. It is important how the house will be built: from a timber of natural moisture for shrinkage or from a dry timber, which is used for construction immediately for finishing. Atmospheric drying of the timber involves the formation minimum quantity cracks, in contrast to forced drying timber, the manufacturing technology of which can be violated, especially during the hot construction season.

Ask the suppliers of wooden lumber about the presence of a compensation groove in the timber. The unloading cut, although it does not completely save from the formation of cracks, but significantly reduces their number.

When inspecting the supplied wooden building material, pay attention not only to the side parts, but also to the ends of the beam, which can tell a lot about the quality of the log used in the manufacture of the beam.

Both stone and wooden, the process is quite complicated. In order for you to live in the house happily ever after, you need to take care of the house. Sometimes to repair something, to finish building something. If during drying all the moisture from the wood did not evaporate, and you purchased a poorly dried beam, then with a high degree of probability we can expect cracks on the facade of wooden drying. Such cracks are the reason why cold will penetrate inside the building. In the worst case, the wall may still be blown. Consider where cracks can appear from and what measures you can take to eliminate them yourself.

Typically, the drying rate of wood is 1 cm in 5 months. For a house measuring 1 50x1500mm, it will take 5-6 years for the wood to completely dry out, stop cracking and shrinking. As experts say, at the sight of cracks on the facade wooden house you shouldn't panic. They can even be left as a highlight in the interior. But only until the crack width becomes more than 2 cm. Wood with cracks of such a width will not remain intact for a long time. If we talk about the depth of cracks, then the maximum depth that is acceptable is 5 cm. Deeper cracks will harm your home.

The reasons why the beam is cracking

The very first and most common cause of cracks is the poor quality of the material. It all depends on how well beam was dried. It should be borne in mind that the outer layer of wood dries much faster than the inner one. Therefore, the outer layer cracks and decreases in size, which leads to cracks. Usually, after the construction of a wooden house is completed, it is worth monitoring the appearance of cracks. In two or three weeks, they may appear on the facade of the house. After a month has passed, beam should dry completely, and the cracks will reach 2-3 cm. There is a chance to prevent the appearance of cracks for this reason by drying beam on one's own. To do this, lay out in the shade beam rows, observing two details. The first detail - the wood should be raised at a distance of 30 cm from the ground and laid in rows, and the second detail - there should be “gaskets” of boards between the rows so that air can freely pass between them.

The second reason why cracks may appear is if the load on the frame was incorrectly calculated. In this case, it does not even matter whether the wood is well dried or not. To eliminate this cause for the appearance of cracks, you need to be careful at the design stage. You need to check all rack loads in the project. If necessary, add more to relieve the total weight of the roof.

The third reason is already improper installation, when cracks appear at the junctions of the logs. For this reason, the appearance of "cold bridges" should not be surprised. To eliminate this cause of cracks, even at the construction stage, it is necessary to fit all the details of the log house tightly to each other. In places where windows and doors will be installed, special expansion gaps must be made. This will reduce the load on the walls, and therefore, the risk of gaps between the logs will decrease.

The fourth reason for the appearance of cracks in wood is related to heating. Not quite competent specialists can start to fuel wooden house in the first season. This leads to the fact that cracks appear both outside and inside. Temperature fluctuations are not good for wood. Due to such a difference, the humidity in the logs changes, which contributes to the appearance of cracks. It should be remembered that beam should not “know” what heating is for one year, but preferably two years.

The most famous ways to get rid of beam from cracks - this is with the help of a seam sealant, PVA and sawdust. You can purchase joint sealer at any store that specializes in building materials and related items. The advantage of this method is that it is easy to match the sealant to the color of the wood. The downside is that shrinkage occurs during use of the sealant, so you will have to apply the sealant again after a couple of days. Usually this method is suitable for the elimination of cracks, the width of which is up to 1 cm. For cracks already much larger, a proven method is used by many specialists. We prepare small sawdust, and then we buy PVA glue. Both ingredients are mixed together until smooth. We close the cracks with the same mass and leave for 2-3 hours. The result justifies all hopes. You can also choose wood that will be the least susceptible to cracking. The most resistant is considered to be wood from the northern regions. But the wood of southern tree species is not so resistant. In it, cracks can appear very quickly and reach the middle of the log. Another way to prevent cracks in wood is to finish the ends. In order for it to work, the processing of the ends must be carried out during the natural drying of the wood.