How to repair cracks in timber? How to hide cracks in laminated timber? Cracks in timber - what to do? Does profiled timber crack badly?

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

Note that the instructions state: the moisture content 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, while bound moisture leaves very slowly.

Features of dried timber

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

Types of timber

Experts clarify how to dry timber with different shrinkage coefficients:

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

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

Properties of dried lumber

Let's summarize the goals of drying timber:

• increase the safety of the material;
• enhance strength properties;
• avoid the appearance of cracks;
• strengthen connections;
• simplify construction work;
• increase insulating abilities;
• protect the wood by painting immediately after installation;
• reduce 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 sheds in the open air for several months.
• We will cover their ends with glue or lime to avoid cracks.
• But due to changes in weather, humidity and temperature, the material sometimes becomes deformed and small cracks form.

Chamber

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

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

Note! Freshly sawn it already has 20% moisture content.

Generator

Drying with high frequency generators.

• Here the wood in the circuit of this generator is the dielectric in the capacitor ( Electric Energy served alternating current turns into heat).
• The timber, when heated, dries intensively and evenly.
• But the energy costs are significant, which means the price of the 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 occurs through convection.

There are 2 types of such cameras.

• Channel dryers continuous action, where the stacks are continually pushed further into a drier place in 4 to 12 hours. We load the tunnel from the “wet” edge, and unload it from the opposite, “dry” edge.
• Special batch drying kilns are smaller than tunnel kilns and may only have 1 door. But environmental parameters, airflow, ventilation reversal guarantee perfect drying. After drying is completed, the chamber is completely emptied and loaded with raw logs, which increases energy losses by 20% than in tunnel chambers.

Condensation

• The condensation chamber collects evaporated moisture on the coolers and discharges it into the sewer system.
• But here the heat pumps do not produce high temperatures, so the cycle is slower.
• Electricity is provided by the cooler compressor.

Innovative

• Vacuum chambers with a pressure of 0.5 bar speed up the drying of the timber with a complete absence of warping and cracking.
• 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 using one of the following methods.

Natural drying

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

Conditions for proper drying:

• Selection of material of the same thickness and type.
• Straight stacked material: Straight stacks and trellises between rows will increase air circulation.
• Pads at the base.
• Pegs under each other and intermediate boards in a row with pegs;
• Optimal air movement: not dense placement, so that the air flows horizontally.
• Air dampers for uniform ventilation of stacks.
• The canopy will protect from rain and sun, and a ventilated area of ​​the site will speed up the process.

Note! Long-term drying of timber drying timber at home guarantees humidity less than 18%.

Thermal chamber

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

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

Conclusion

• We carry out primary drying in warm air, minimal humidity, but under natural conditions.
• We build the platform on pillars.
• We place the timber across and lengthwise on thin slats (for free ventilation).

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

Experienced practitioners recognize the degree of moisture from the shavings: they tie long shavings in a knot. If the shavings do not collapse, then the wood is still damp, and if it disintegrates, it is already dry. But let’s pay attention to the core of the timber - it is sometimes wetter, then it’s worth drying a little more.

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

The tree was and remains the most popular material when building a house. This beautiful, environmentally friendly, safe, fragrant, warm material Perfectly suits all different types 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 of timber in wooden house?

Which 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 construction, this will not only significantly damage appearance home, but will also significantly reduce the strength of the building. That's why experts recommend taking a closer look at the condition of your home, keeping an eye out for cracking, and doing everything possible to prevent the cracks from getting deeper.

The initial cause of cracks

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

What kind of wood is best to take for construction?

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

Reasons for cracking of timber in a finished house

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

1. Spring sun. To prevent the wood from cracking in the spring, experts advise taking measures and protecting the house with special protective materials that will prevent moisture from evaporating from the wood.
2. Warmth from stove heating. Not only the sun, but also the usual stove can dry out wood. But if the sun does it from the outside, then the furnace does it from the inside. For 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 of timber in a wooden house? It is enough to follow some rules, and there will be significantly fewer 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 with utmost precision, it is unlikely that it will ever become covered with cracks.
• From March to May, the house should be covered with ultraviolet protection products.
• During the construction and settling of a 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 timber to dry out.
• To care for wooden building we need better stuff. Most suitable option– those that contain not only filters from ultraviolet radiation, but also linseed oil.

What if cracks appear?

Cracks that appear must be repaired quickly so that moisture does not evaporate through them, otherwise the timber will crack even more. Sealant, ordinary putty and caulking are suitable for closing. Paint is applied on top. If cracks appear inside the rooms, they are covered with sawdust and plastered. But when large cracks appear, you will have to use sealant.

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 is it advisable to seal cracks in timber?

Small cracks on the surface of the wood do not affect negative influence for the operation of the building. Most often they can be of the nature decorative element, giving the logs some individuality. But still, the appearance of cracks should not be treated negligently.

If cracks in timber are more than 5 mm wide and spread throughout the entire log or timber, then measures must be taken to prevent their spread. Why do this?

• 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 detected, they must be repaired immediately.

Prevention of cracks

To prevent cracks from appearing in timber, a number of measures must be taken.

Sealing cracks in timber:

Preventive measures help prevent the occurrence of large quantity cracks, but they are not able to completely eliminate their formation. Can be hidden cracks in timber, prevent rotting processes in them by sealing.

Sealing cracks in timber possible different ways. The materials most often used for this are air-hardening putties, dry mixtures, and sealants.

Methods for sealing cracks in timber

The methods described above for sealing cracks can be used both outside and inside a timber house. All methods do not harm the wood, help remove cold bridges and increase the strength of the tree.

Hello, our dear readers. Owners of your own wooden houses and those of you who are just planning to build them. Today we will talk about such a well-known problem as cracking of lumber.

After all, there is no greater sadness than watching the appearance of more and more cracks on the walls of your still not really inhabited home, in the construction of which, by the way, a lot of nerves, labor and money were invested.

So the question arises: what can be done to prevent the timber from cracking, what and how to treat it? But is it formulated correctly? And is it really possible to save wooden facade presentation using only impregnations and lotions?

Why does timber crack?

Before you protect something or prevent something, you need to understand the very mechanisms of the problem, or all your actions, even if there is quality materials will never be effective.

So, the reason for cracking of wood is “buried” in its uneven drying. It's no secret that after loss of moisture, timber noticeably loses in volume. This is where the whole problem lies.

It is logical that the upper layers of the tree dry out faster and decrease in volume, but the core, which is deeper and therefore dries out more slowly, does not keep up with such a pace.

As a result, the tree (those top layers) cannot stretch and crack. Moreover, the more unevenly the shrinkage occurs, the deeper and more numerous the gaps will be.

A particularly problematic area in this regard is the ends of the timber. Along the cut plane, along the grain, the wood loses moisture even faster, which means it is subject to even more cracking.

Ideally, the wood should dry evenly and very slowly so that unnecessary stress does not arise in it, and all layers lose volume in an equal percentage, as a homogeneous product.

But, unfortunately, this does not guarantee the integrity of the material. The point is to create ideal conditions for lumber, it is possible only at the stage of its preparation. This is done in special drying chambers using vacuum and microwave technologies.

But the joke is that wood has the ability to absorb moisture from the surrounding air, accumulate it, and when weather conditions change, lose it again according to the pattern described above, that is, unevenly.

And this process is endless. You won't build an owl's house in drying chamber. And on fresh air he will quickly find a reason to crack.

How to extend the shelf life of a house made of timber?

Knowing about the upcoming problem before construction begins, you can thoroughly prepare for it and significantly extend the life of your future home. Believe me, over the centuries-old history of building log houses, craftsmen have found more than one way to deceive nature.

Calibration

Everything in this world moves along the path of least resistance, so most cracks appear on the edge of the beam that is closer to the core of the material. But what does this give us?

A lot, actually. If you take this fact into account when building a house, and hide problem areas inside or between the crowns, the facade will remain free of defects longer, and the cracks themselves, when they appear, will be insignificant.

Of course, all this applies to ordinary non-profiled timber. A comb already created by the manufacturer will not give you any freedom to maneuver.

Compensation cut

But you must admit that in the realities of mass production, keeping track of the fibers is quite troublesome. This will greatly reduce the speed of work, and therefore increase the cost of the finished product, ultimately reducing its competitiveness. Although if there was no other choice, they would have done so. We calibrated the logs manually, made notes for the front side, but why?

The problem can be easily solved using expansion joint. Indeed, why allow spontaneous ruptures to occur when you can carry out a neat, civilized cut?

Through it, moisture will leave the tree more evenly, and there will be no cracks. The cut will just widen a little and that’s it. Of course, such a trick will be clearly visible at the open ends and even such technical cracks will have to be caulked, but it’s better than the tree itself cracking wherever it wants.

Impregnations

This is how we gradually reached construction impregnations. Along with antiseptics and fire retardants, there are also compounds that slow down the process of moisture evaporation.

And here keyword they “slow down” If you completely make the surface of a tree vapor-tight, it will simply begin to rot. But with slow evaporation, the moisture in the core has time to rise to the surface, and therefore the tree dries out much more evenly.

In particular, similar paints and impregnations are often used to open the ends and joints of timber, and not at all because of cracks. Having the opportunity to remove moisture along the fibers, lumber shrinks more significantly towards its edges than in the middle, and this leads to the appearance of inter-crown cracks, for which corners are so famous in a wooden house.

But everywhere has its advantages and disadvantages. Many people cannot afford colorless expensive impregnations, and the composition of the solutions is not very natural. Cheap ones are not as effective, have a far less woody color and are often difficult to use.

Confused?

Then let's talk about them in a little more detail.

How to treat timber

Now that we know where the legs of our problem come from, and how all this can be solved, let’s see what can really be used to treat the ends of the beam so that it does not crack.

Lime

Lime is a cheap natural antiseptic, but few people know that it protects wood well from solar ultraviolet radiation and prevents it from drying unevenly.

However, do not rush to take up the popcorn. Firstly, lime is washed off very quickly, and secondly, it does not have the most pleasant color.

Would you like the ends of your beautiful log house to turn white with stains? Agree, this protection is for the most extreme cases.

Dye

You can also protect the ends with any breathable paint. Today there are more than enough of them on sale. But, again, the wood texture will be lost, but the capillarity in the beams will be completely killed. It’s a fact that if you paint pre-kiln-dried wood with good paint, the likelihood of it cracking will be minimized.

Another thing is that supplied to coatings market They are in no way inferior in cost to specially developed impregnation, and more often than not they cost significantly more, so what’s the point in reinventing the wheel?

Wax

Another remedy we inherited from our ancestors is beeswax. The ends sealed with it remain transparent for steam exchange, but not for moisture. Plus, this material is of natural origin, 100% safe for human life and time-tested.

Another thing is that working with such a product is extremely inconvenient; it requires constant heating, and also makes the wood more susceptible to fire.

True, today manufacturers have refined the idea of ​​their ancestors and created wax-based mastics that are easy to use, which, in addition to the properties described above, improve mechanical properties wood and give it a beautiful silky shine. The only problem is the price. Not everyone's budget allows them to purchase such a miracle.

Polymer impregnations

Along with natural ones, there are also polymer impregnations on sale. The same "Senezh Tor", "Neomid Tor Plus" or "Biotor" from trademark Rogneda. These compounds are pure chemistry.

But they do their job perfectly, are relatively cheap, easy to use and colorless. If you need wood texture in pure form, you can’t do without polymer.

Only supporters of “green” housing will remain dissatisfied here. And this is logical. The meaning of building from natural materials a house and then saturate it with chemicals?

In a word, how to care for your log house and what impregnations or mastics to choose for this is a personal matter for the owner. It is enough to know that today there is a choice and cracking, which was perceived by many as a death sentence, is quite possible to avoid, or at least minimize it.

With this we say goodbye to you. Goodbye and see you soon on the pages of the site about the dacha.

Causes of cracks in timber and ways to prevent their formation

1.Cracks in timber are formed due to uneven shrinkage

Cracks in timber occur because the humidity inside the timber is higher than outside. Thus, the outer part of the bar “breaks”, because she is bursting 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 breaks in wood, formed under the action of internal stresses reaching the tensile strength of wood across the grain...”. There are different types of cracks in lumber, but in this article we discuss cracks shrinkage, the reasons for their occurrence and ways to overcome their occurrence in timber.

The moisture content of the timber and its drying affect the quality of the wood of the building material. Drying can be atmospheric or chamber: in the first case, the timber dries out naturally, and in the second case, it is forced. The formation of cracks in the timber depends on how chamber drying is carried out and 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 humidity in the wooden building material and leads to the formation of internal stress in it.

During atmospheric drying, the timber naturally reaches the required humidity, while shrinking in the log house 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 values) with the external one, because in a natural environment, the air humidity is higher than in the drying chamber, which smoothes out the effect of wood expanding from the inside. Simply put, when drying 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 purchasing a log house made from kiln-dried timber in order to get a house immediately without shrinkage, “turnkey”. Such construction is not only much more expensive, because... dry lumber is higher in price due to the electricity consumption for its production, but it also leads to a poor-quality structure - some manufacturers of dry lumber violate the drying technology when drying it at high speed.

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 include steam to prevent cracking of the wood from the outside, to soften it so that internal stress does not tear the outer layers.

2. An expansion groove in the timber helps prevent cracks from forming

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

The unloading cut relieves some of the internal stress in the block, because functions as if artificial cracks - they are made in advance, before real ones appear, but since they are hidden during the assembly of the log house under the lower and upper crowns, they become invisible and do not spoil general form buildings.

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

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

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

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

3. Other reasons for the formation of cracks in timber

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

You can determine which part of the log the timber was made from by looking at the annual rings on 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 the average person does not pay attention to these details. Therefore, when choosing a building material, consider the timber not only from the sides, but also from the ends.

Thus, in order to build a beautiful and high-quality house from timber, pay attention to the quality of the lumber from which your country building will be built. It is important how the house will be built: from timber with natural moisture for shrinkage or from dry timber, which is used for construction immediately before finishing. Atmospheric drying of timber involves the formation of a minimum number of cracks, in contrast to forced drying timber, the manufacturing technology of which may be disrupted, especially during the hot construction season.

Ask your lumber suppliers about the presence of an expansion groove in the timber. Although the unloading cut does not completely prevent the formation of cracks, it 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.