Let's talk about one of the problems in the construction of a wooden or frame house, about cracks in the timber. Consider the causes of the appearance, methods of elimination and prevention.
There is no 100% recipe for preventing wood cracks. Of the most suitable methods of protection is drying in vivo, in the bark, without getting sun rays... This drying can take years, depending on the material and thickness of the barrel.
There is also a technique for soaking the forest in sea water within 3 years (for oak), but it is used only in the manufacture of joinery, piece products, as it requires significant costs.
Reasons for the appearance of cracks in the timber
Reason # 1 - initially raw material
One of the reasons is the use of initially raw material, the use of raw material, profiled beams, logs or beams for the uprights of a frame house. As a result, cracks in the timber appear immediately after the timber dries, and excess moisture evaporate.
What if you bought raw material as the uprights of a frame house? Without a special drying chamber, it is necessary to properly lay it out on the street. The distance from the ground is at least 30 cm, then we shift each beam or board so that air passes freely between them. The boards should not bend in the middle or elsewhere.
The most important thing is that the drying of the tree should take place without the participation of the sun, i.e. in full shadow. The timber should dry up to 14% moisture. Only then can our timber be treated with an antiseptic and used in frame construction.
Cracks appear in a log house no matter how high quality it was raw material... This does not mean that then you can take cheaper and "damp", since besides cracks, there are other motives, because of which you should choose high-quality, dry wood.
Since one half of a bar or log wooden house is outside, and the other part is inside the house, then moisture absorption and shrinkage occurs unevenly, depending on weather conditions.
Consequently - outer side often cracks from stress, and these cracks cannot be avoided. And if, after a few years, you do not like the appearance of your country house, You can do outer skin through counter. rail. As a cladding, you can use an imitation of a bar or an imitation of a log - a block house.
The second reason may be the incorrect load on the frame post. Although it was in frame house this is not easy to do. After all, the house itself is quite light, the loads on the racks are distributed evenly and they are quite small, given the number of racks.
But still, there are single columns (15x15 or 20x20 timber) that are installed inside a frame house in order to reduce the number of walls and partitions.
Poor construction of timber or frame house structures can add more cracks and other problems such as gaps between logs or beams.
And if there are cracks, then there will already be a loss of heat, blowing out. All details of the house must be clearly adjusted to each other. In window and door structures gaps must be provided, do not forget that the wooden house is constantly in motion, especially in the first, second season.
Reason number 3 - artificial heating at home
And the last thing is artificial heating at home. A log house before heating with all possible in modern ways should stand for one year. Actually, both windows and doors in it also need to be installed only on next year after the house itself is built.
Surge heating has a detrimental effect on a wooden house.
Imagine: it's wet outside, the tree has accumulated moisture inside, outside, a week later you arrived, turned on the heating everywhere and dramatically dried the whole house.
On Sunday, you left your property, turned off the heating. Again the change in temperature and humidity. Such intermittent heating cannot have a positive effect on wooden house... It is advisable to maintain a certain temperature, including in winter.
How to repair cracks in a log, timber
There are currently two main ways to repair cracks. The first method is to sell a specialized joint sealant for wooden structures, including beams and logs. Also, these sealants can be matched to the color of your home, making it invisible. Everything here is simple and clear, we go to the hardware store, buy, close up.
When it comes to frame construction, we will check our frame struts for cracks. In addition to sealants, a putty for wood based on PVA, etc. is sold, there is also a putty with shades for wood. It can only be used for finishing works, for example, sealing problem areas on the inside fine finish... There is the best and easiest way to seal cracks in the frame post.
To do this, we need small sawdust, which we collected in advance in a container.
And also PVA glue or impregnation, drying oil can be used. This glue is intended for gluing wood, paper. We mix it in a separate container with our sawdust, mix it, bring it to a homogeneous mass.
After that, we fill the cracks in the timber with the resulting mass. In a few hours, this mass will solidify. Good bonding and sealing. In the end, it looks like this:
So far, we have spoken to you about small cracks in wooden structures Houses.
What if the crack in the frame post is very large?
There are two options here, and it is necessary to choose according to the situation: whether the rack is an important support or not, how big is the crack.
- You can install a duplicate support, or even replace the stand, if possible;
- You can use steel U-shaped brackets according to the size of the bar. They will prevent further cracking, as well as carry out the procedure for sealing the crack using PVA glue or special sealant. The use of polyurethane foam is not permitted.
Houses made of profiled timber are considered the most convenient and comfortable to live in, moreover, very attractive. After making this material already has a great appearance, so, by and large, it does not need finishing. Many owners log houses they don’t do it. But over time, the owners begin to notice that on level and smooth walls cracks are formed.
Why does profiled timber crack? and how dangerous is it? Let's try to answer these questions.
Reasons for cracking timber
There is such a science - "wood science". According to her, wood in the process of drying can decrease in size, that is, dry out. In particular, the drying out of pine will be, as a percentage:
- across the fibers - 3-5%;
- along the fibers - 0.1-0.3%.
The shrinkage of external and inner layers... For example, in the same pine, the dimensions of the inner layers decrease by 2.91%, and the outer ones by 8.22%. But this is only if the wood dries naturally. If the production of profiled timber is carried out from a pre-dried material, it cracks much less, and the size of the cracks is not very large.
In addition, during shrinkage, tensile stresses act on the surface layers, and compressive stresses on the inner ones. It often happens that their value becomes greater than the tensile strength of the tree, as a result of which the upper layers crack. The same situation is observed not only with profiled timber, but also with rounded logs. Therefore, for natural drying the outer layers dry first, after which the inner ones. This means that in any case, the timber and logs will crack. The only thing that can be done in this case is to reduce the size of the cracks.
Wood protection methods
Now you know, why does the profiled timber crack?... There are several ways to deal with this. Here are the most common ones:
- Dry for a long time. It will take at least two years for the logs to dry completely. Only then they will not crack so much, and the size of the cracks will be within 1-2 mm.
- Make a compensation cut. The effectiveness of this method is in question, there are still disputes about its feasibility and safety.
- Drying with high-frequency currents - in this case, the process occurs as if from the inside - first the insides dry, and then the surface. However, the cost of a tree dried in this way is simply transcendental. In addition, some experts are not sure about the harmlessness of exposure to high-frequency currents.
- Chamber drying is the most preferred method. Thus, most manufacturers dry the material.
How dangerous is cracking
While lumber manufacturers and sellers of specialty crack bridging products do their best to reassure buyers of the dangers of cracking, the reality is not so bad. Here are the arguments they make:
- If the timber cracks, then when moisture gets in, it freezes in winter and can break it.
- As a result of cracking, rotting begins.
- Insect pests accumulate in the cracks.
- Thermal insulation properties houses are down.
To be convinced of the controversy of these statements, it is enough to go to the nearest village and look at the houses there - the walls are simply teeming with cracks. Nevertheless, the people living there do not notice any danger.
The question of how and how to repair cracks in a timber is relevant for all owners of wooden structures. Construction from natural wood is not only a tribute to fashion. Timber structures are lightweight, environmentally friendly and have excellent insulating qualities. Their construction is carried out in a short time. For wooden log cabins, there is no need to build a heavy and powerful foundation. Their durability is also an important factor. But all this is possible only on condition correct operation and timely maintenance of buildings.
Cracks in the timber are a sign of a violation of the operating conditions of the structure or even its complete destruction.
One of the factors that can lead to a building losing its functionality is cracks in the timber, which can be called the "scourge" of all wooden structures.
The damage caused by cracks in wood
Time spares nothing. Even the most quality wood over time, it begins to be covered with a network of small cracks. This is a process that occurs due to the natural shrinkage of the material. Outwardly, it looks quite exotic and natural. Such a web acts as an element of wall decor and serves as a kind of decoration for the building.
Property owners do not attach such " exterior decoration»Due importance, considering that it has no effect on the strength and characteristics of the building.
It’s completely in vain.
Slots in the timber can cause a violation of the operational characteristics of the structure or its complete destruction.
Cracks appear due to different rates of moisture removal from different layers of the log. It evaporates much faster on the outside than in the middle. The resulting stress causes the material to rupture.
Below are the destructive factors that cause cracks in the wood:
- Longitudinal cracks that run along the entire length of the product reduce its strength and can cause complete destruction of the timber.
- The part gets into the openings rainwater and snow. This causes dampness and decay of the material. After a short period of time, the entire wall can be hit.
- Water trapped in the cavity of the wall freezes in winter, expands and destroys the structure of the tree. In addition, it causes deformation of the entire structure. This phenomenon can lead to the destruction of all communications (heating systems, water supply) and the rupture of electrical wires.
- The holes in the tree can serve as a kind of home for many insects. Ants, bark beetles, bees or wasps can settle in the cavities. Few people will like such a neighborhood. Bark beetles can completely destroy a log house in a few years.
Thus, sealing cracks in the walls of timber buildings becomes a vital issue, the solution of which must be given due attention, time and money.
Prevention measures
It is necessary to think that cracks are a serious enemy of the structure even before construction begins. Moreover, several years before it began. If you build from dry material, then the likelihood of surface destruction is significantly reduced. When the moisture content in all layers of the product is the same, then tension will not arise in them. Therefore, the likelihood of cracking is greatly reduced.
In order to avoid a web of cracks, the following measures are taken:
- Long-term drying. This is necessary in order to remove moisture from the wood as much as possible. The logs should be kept cool and cold for 2-3 years. dark place... Their position must be rigidly fixed. This will prevent them from bending. Logs can be processed when the moisture content of the material drops to 18-20%. In this case, the maximum crack width will not exceed 5 mm. It is much easier to deal with such flaws than with those that are formed in undried material.
- Sealing the ends of the timber. The ends of the logs dry much faster than the rest of the surface. This is due to the structure of the wood. As a result, the ends are covered with cracks and cracks in the first place. Through them, an abundant release of moisture is carried out. A similar situation can lead to deformation of the timber and a violation of the tightness of the wall. You can close up the ends oil paint, carpentry varnish, facade sealant, wax or drying oil. After that, the evaporation process will slow down and shrinkage will occur evenly.
- Compensation cuts. This preventive measure helps to avoid the appearance of many small cracks, since the stress of the material when the timber deforms will compensate for the kerf. It is done with a depth of one third of the diameter of the log and a width of 7-10 mm. To do this, you can use a regular chainsaw or hand cutter... The cut is made in the upper part of the product: this way it will be covered and protected by the bar lying on top. It is better not to bring the opening to the end: this way the wood will be protected from moisture and insects. The cavity can be laid with tow or moss. This material will compensate for fluctuations in moisture.
But, despite all the preventive measures, cracks on the walls wooden frame can not be avoided. This natural property wood. You can only eliminate its consequences.
How and how you can fill up the cracks in the timber
Building wooden houses has a thousand-year history. During this long period, mankind has learned to eliminate the consequences of wood shrinkage and shrinkage of buildings. New technologies have significantly expanded the range of materials used for embedding facades and options for their use.
So, to eliminate cracks in wood, the following methods are used:
To seal cracks, you can use a mixture of sawdust and PVA glue.
- Application of a stub. The plug is a regular piece of wood cut to fit the hole. Hammer it with a hammer. It is not recommended to use excessive force when driving the wedge - this can split the wood. Since it will continue to dry out, PVA glue must be applied to the wedge. The place of repair is sealed with putty or a solution made of sawdust and glue.
- Sealing with homemade putty. Small sawdust and PVA glue are used as ingredients. The consistency of the mortar should correspond to the usual wall putty. The cavities are filled with material using rubber spatula... After it dries, the next layer is applied. After that, the surface is smoothed and polished. For improvement appearance the place of repair can be tinted.
- Use of facade sealant. This is a new unique product of the chemical industry. The sealant has high adhesion and is environmentally friendly. It can deform, changing in size up to 25% of the volume, without loss technical characteristics... In this case, the temperature range at which the sealant can be used is from -50 ° C to + 50 ° C. The material is placed in the cavity using glue gun... After that, the surface is leveled.
- Application of wood putty. This material can be used to seal both end and longitudinal cracks. It should be borne in mind that holes with a size of no more than 3 mm can be processed with this composition. Otherwise, the material will fall out quickly. It should only be applied on a dry surface. Sold putty in a ready-to-use color natural wood... No additional finishing is required after application. The material is resistant to water, frost and ultraviolet light.
- Caulking. This is an ancient way of repairing wooden log cabins, tried and tested for centuries. To seal the cavities, ordinary moss is used, of which there is a lot in the forest. The good thing about moss is that this material has a very low degree of thermal conductivity. Embedding with moss is additional thermal insulation. Caulking is carried out with a well-soaked and squeezed material. It is tamped tightly into the holes with a wooden spatula. As it dries, the moss expands and fills in the smallest gaps. The protruding excess is carefully cut off. This method is environmentally friendly and does not require capital investments.
The durability of the structure depends on the quality of the drying of the wood, otherwise the timber may bend over time, rot, and insects and fungus will surely start in it. So how to dry the timber without cracks and residual harmful moisture? After all, only proper drying will improve the mechanical properties of wood, prevent warping, decay and cracking.
Note that the instruction states: the moisture indicator indicates the amount of water in the wood. By the way, this moisture is both free and bound. But free moisture evaporates well, making wood lighter, and bound moisture leaves very slowly.
Features of dried timber
It is clear that moisture from the outer layers evaporates intensively first. This is what creates great stress in the wood: surface tension and the appearance of cracks.
Varieties of timber
Experts clarify how to dry a beam of different shrinkage coefficient:
- low-withering - pine, spruce, fir, white poplar, cedar;
- moderately dry- beech, oak, aspen, elm, black poplar, ash, small-leaved linden;
- severely dry- hornbeam, Norway maple, birch, larch.
Percentage = mass of water in wood / mass of dry wood.
Dried lumber properties
Let's summarize the goals of drying the timber:
- to increase the safety of the material;
- enhance strength properties;
- avoid cracks;
- strengthen connections;
- simplify construction work;
- increase insulating capacity;
- protect the tree with paint immediately after installation;
- reduce the inevitable changes to the finished building;
- improve the surface without additional cladding.
Ways to create a dried timber
Atmospheric, natural
- We store the beams in stacks under awnings on outdoors several months.
- We cover their ends with glue or lime to avoid cracks.
- But from changes in weather, humidity and temperature, the material sometimes deforms, small cracks form.
Chamber
Chamber drying is a highly efficient alternative to the atmospheric method.
- The timber in drying chambers, equipped with heating heaters, fans, air ducts, promote uniform, correct drying.
- The effectiveness of such drying is undeniable: we are not dependent on the weather, and the process is controlled by a computer, reducing the time, but increasing the volume.
Note! Freshly sawn it already with 20% moisture.
Generator
Drying with high frequency generators.
- Here, the wood in the circuit of this generator is a dielectric in the capacitor ( Electric Energy supplied alternating current turns into heat).
- The timber, when heated, dries intensively and evenly.
- But the costs of electricity are significant, which means that the price of a bar is higher. By the way, ready-made dry timber is always 2 times more expensive.
Types of drying chambers
Convective
In convective chambers, energy is supplied to the wood from the air circulation, and heat transfer - by convection.
There are 2 types of these cameras.
- Continuous duct dryers, where stacks are constantly pushed further into a drier place in 4 - 12 hours. We load the tunnel from the “wet” edge, and unload it from the opposite, “dry” one.
- Batch dryers are smaller than tunnel kilns and can only have 1 door. But the parameters of the environment, the blow-through rate, and the ventilation reversal guarantee perfect drying. After the end of drying, the chamber is completely emptied and loaded with damp logs, this increases the energy loss by 20% than in the tunnel chambers.
Condensing
- The condensation chamber collects the evaporated moisture on the coolers and discharges it into the sewer.
- But here heat pumps do not give high temperatures so the cycle is slowed down.
- The electric power is provided by the refrigerant compressor.
Innovative
- Vacuum chambers with a pressure of 0.5 bar accelerate the drying of the timber without warping and cracking.
- Microwave cameras, electromagnetic dryers are also innovations, just like 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 felling a tree under a bar: in autumn and winter there is no sap movement, 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 trellis between rows will increase air circulation.
- Base pads.
- Pegs under each other and intermediate boards in a row with pegs;
- Optimal air movement: not tightly packed so that air can pass horizontally.
- Air dampers for uniform ventilation of the stacks.
- The canopy will protect you from rain and sun, and a ventilated place on the site will speed up the process.
Note! Long-term drying of the timber drying timber at home guarantees humidity less than 18%.
Thermal camera
- Simulated dryer: non-residential premises With brick stove and heating along the walls.
- We build stacks with our own hands, lay trellis 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 facilities and dryers.
Conclusion
- The primary drying is carried out in warm air, minimum humidity, but in natural conditions.
- We build the platform on pillars.
- We put the timber across and along the thin strips (for free ventilation).
The moisture level of the resulting dried wood at home is not easy to find out. 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 the long shavings in a knot. If the shavings have not collapsed, then the wood is still damp, and if it decays, 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.
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 lumber cracking.
After all, there is no more sadness than to observe the appearance of more and more cracks on the walls of your even not really inhabited housing, in the construction of which, by the way, a lot of nerves, labors and funds were invested.
So the question arises: what can be done so that the timber does not crack, how and how to process it? But is it formulated correctly? And is it really possible to keep u wooden facade presentation, using only impregnations and lotions?
Why does the timber crack?
Before protecting something and hindering something, you need to understand the mechanisms of the problem, or all your actions, even if there is quality materials will never be effective.
So, the reason for wood cracking is "buried" in its uneven shrinkage. It's no secret that after the loss of moisture, the timber noticeably loses in volume. This is the whole problem.
It is logical that the upper layers of the tree dry out faster, decrease in volume, and the core, which is deeper, and therefore dries up more slowly, does not keep up with such a rate.
As a result, the tree (the very top layers), due to the impossibility of stretching, cracking. Moreover, the more unevenly the shrinkage takes place, the deeper and more numerous the breaks will be.
Especially trouble spot in this regard, the ends of the timber are. Along the plane of the cut, along the fibers, the tree loses moisture even faster, which means it is subjected to even greater 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, like a homogeneous product.
But, unfortunately, this does not guarantee the integrity of the material. The point is what 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 a tree has the ability to absorb moisture from the surrounding air, accumulate it, and when the weather conditions change, it again loses it according to the above-described scheme, that is, unevenly.
And this process is endless. You will not build an owl house in drying chamber... And on fresh air he will quickly find a reason to crack.
How to extend the shelf life of a log house?
Knowing about the upcoming problem even before the start of construction, you can thoroughly prepare for it and significantly extend the life of your future home. Believe me for centuries-old history the construction of log cabins, the masters 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 that edge of the bar, from which it is closer to the core of the material. But what does this give us?
In fact, a lot. If we take this fact into account when building a house, and hide problem planes 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 is applicable for ordinary non-profiled timber. The 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 fibers is quite troublesome. This will greatly reduce the speed of work, and therefore increase the cost of the finished product, and ultimately reduce its competitiveness. Although if there were no other choice, they would have done so. We calibrated the logs by hand, made notes for front side, but why?
The problem can be easily solved with an expansion joint. Indeed, why allow the appearance of spontaneous ruptures, 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 spread out a little in breadth and all business. 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 will crack itself wherever it pleases.
Impregnation
This is how we gradually came to construction impregnations. Along with antiseptics and fire retardants, there are also such compositions that slow down the process of moisture evaporation.
And here the key word is “slow down”. If you completely make the surface of the tree vapor-proof, it will simply start to rot. But with slow evaporation, the moisture in the core gets time to rise to the surface, and therefore the tree dries up much more evenly.
In particular, they often open the ends and joints of the timber with such paints and impregnations, and not because of cracks at all. Having received the opportunity to remove moisture along the fibers, the lumber to its edges gives a more significant shrinkage than in the middle, and this leads to the appearance of inter-crown gaps, for which corners are so famous in a wooden house.
But there are advantages and disadvantages everywhere. Colorless expensive impregnations are too expensive for many, and in terms of their composition, solutions are not very natural either. Cheap ones are not as effective, are far from woody and are often difficult to use.
Confused?
Then let's talk a little more about them.
How to process the timber
Now that we know where our legs grow from, and how all this can be solved, let's see what it is really possible to process the ends of the timber 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 its uneven drying.
However, do not rush to tackle the bakeware. Firstly, the 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 from stains? Agree, this protection is for the most extreme case.
Dye
You can also protect the ends with any breathable paint. Today there are more than enough of them on sale. But, again, the woody texture will be lost, but the capillarity in the bars is completely killed. Fact - there is a fact, if you open the previously passed chamber drying wood with good paint, the likelihood of cracking is minimized.
Another thing is that the paintwork materials supplied to the market are in no way inferior in their cost to a specially developed impregnation, and most often they cost much more, so then it makes sense to reinvent the wheel?
Wax
Another tool that 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 even makes the tree more susceptible to fire.
True, today manufacturers have finalized the idea of their ancestors and created on the basis of wax convenient mastics, which, in addition to the properties described above, improve mechanical properties wood and give it a beautiful silky sheen. The only problem is the price. Not every budget allows you 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 brand Rogneda. These compounds are pure chemistry.
But they do an excellent job with their task, are relatively cheap, easy to use and colorless. If you need wood texture in pure form, polymer is indispensable.
Only adherents of "green" housing will remain dissatisfied here. And this is logical. The meaning is to build from natural materials a house, so that it can be impregnated with chemistry later?
In a word, how to take care of your log house and what impregnations or mastics to choose for this is a personal matter of the owner. It is enough to know that today there is a choice and cracking, which was perceived by many as a sentence, is quite realistic to avoid, or at least minimize it.
On this we say goodbye to you. Goodbye and see you soon on the pages of the site about the dacha.