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 occurrence, ways to eliminate and prevent.
There is no 100% recipe for preventing cracks in the forest. Of the most suitable protection methods - is drying in natural conditions, in the bark, without getting sun rays. Such drying can take years, it all depends on the material and thickness of the trunk.
There is also a method of 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.
Causes of cracks in the beam
Reason number 1 - initially raw material
One of the reasons is the use of initially raw material, the use of raw material, profiled timber, logs or timber for the frame house racks. As a result, cracks in the timber appear immediately after the timber dries, and excess moisture will evaporate.
What if you bought raw material as the studs of a frame house? Without a special drying chamber, it is necessary to properly decompose it on the street. The distance from the ground is at least 30 cm, then we shift each beam or board so that air can freely pass between them. Boards should not sag in the middle or in other places.
The most important thing is that the drying of the tree should take place without the participation of the sun, i.e. in complete shade. The timber should dry to 14% moisture. Only after that it is possible to treat our timber, including with an antiseptic and use it in frame construction.
In a log house, cracks appear no matter how high quality it was. raw material. This does not mean that then you can take it cheaper and “raw”, because apart from cracks there are other motives, because of which you should choose high-quality, dry wood.
Since one half of a beam or log wooden house is outside, and the other part is inside the house, then the absorption of moisture and shrinkage occurs unevenly, depending on weather conditions.
Consequently - outer side more often it cracks from stress, and these cracks cannot be avoided. And if in a few years you don't like the look of your country house, You can do outer skin through counter. rail. As a sheathing, you can use an imitation of a beam or an imitation of a log - a block house.
The second reason may be an incorrect load on the frame rack. Although it is in frame house it is not so easy to do so. 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 (beam 15x15 or 20x20), which are installed inside the frame house to reduce the number of walls and partitions.
Poor installation of wood or frame house structures can add more cracks and other problems, such as gaps between logs or timber.
And if there are gaps, then there will already be a loss of heat, blowing out. All parts of the house must be clearly adjusted to each other. in windows and door structures gaps should 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 finally, this is artificial heating of the house. Timbered house before heating by all possible in modern ways must last one year. Actually, both windows and doors in it also need to be installed only on next year after the house is built.
Spasmodic heating has a detrimental effect on a wooden house.
Imagine: it is humid outside, the tree has accumulated moisture inside, outside, a week later you arrived, turned on the heating everywhere and dried the whole house abruptly.
On Sunday you left your property, turned off the heating. Another change in temperature and humidity. Such intermittent heating cannot have a positive effect on wooden house. It is desirable to maintain a certain temperature, including in winter.
How to repair cracks in a log, beam
Now there are two main ways to repair cracks. The first way - a specialized seam sealant is sold for wooden structures, including timber, logs. Also, these sealants can be matched to the color of your home, which will make it invisible. Everything is simple and clear here, we go to the hardware store, buy, close up.
If we are talking about frame construction, then we will check our frame posts for cracks. In addition to sealants, wood putty based on PVA, etc. is sold, there is also 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 a frame rack.
To do this, we need small sawdust, which we collected in advance in a container.
As well as PVA glue or impregnation, drying oil can be used. This glue is designed for gluing wood, paper. We mix it in a separate container with our sawdust, mix, bring to a homogeneous mass.
After that, we fill the cracks in the timber with the resulting mass. After a few hours, this mass will harden tightly. Good bonding and sealing. In the end it looks like this:
So far we have been talking about small cracks in wooden structures at home.
What to do if the crack in the frame rack is very large?
There are two options here, and you need to choose according to the situation: whether the rack is an important support or not, how big the crack is.
- You can install a backup support, or even replace the rack, if possible;
- You can use steel U - shaped brackets according to the size of the timber. They will prevent its further cracking, as well as carry out the procedure for sealing the crack with PVA glue or a special sealant. The use of polyurethane foam is unacceptable.
Houses made of profiled timber are considered the most convenient and comfortable for living, and also very attractive. After manufacturing given material already has a beautiful appearance, so, by and large, does not need finishing. many owners timber houses they don't do it. But as time passes, the owners begin to notice that on even and smooth walls cracks are formed.
Why is profiled timber cracking and how dangerous is it? Let's try to answer these questions.
Causes of timber cracking
There is such a science - "wood science". According to her, the wood in the process of drying can decrease in size, that is, dry out. In particular, the shrinkage 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 are reduced by 2.91%, 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 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 act on the inner layers. 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 round logs. Therefore, at natural drying The outer layers dry first, then the inner ones. And 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.
Ways to protect wood
Now you know, why is profiled timber cracking. There are several ways to deal with this. Here are the most common:
- 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 sky-high. In addition, some experts are not sure about the harmlessness of exposure to high-frequency currents.
- Chamber drying is the preferred method. Thus, most manufacturers dry the material.
How dangerous is cracking
Although lumber manufacturers and dealers of specialized crack-sealing products try their best to reassure buyers of the danger of cracking, in fact, everything is not so scary. Here are their arguments:
- If the beam 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 cracks.
- Thermal insulation properties houses are going 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 full of cracks. However, the people living there do not notice any danger.
The question of how and with what to repair cracks in a bar is relevant for all owners of wooden buildings. Construction from natural wood is not only a tribute to fashion. Structures made of timber 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. An important factor is their durability. But all this is possible only if correct operation and timely maintenance of buildings.
Cracks in the beam 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 the building losing its functionality is cracks in the timber, which can be called the "scourge" of all wooden structures.
Damage caused by cracks in wood
Time spares nothing. Even the most quality wood over time, it begins to become 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 finish» of due importance, considering that it does not have any effect on the strength and characteristics of the building.
Absolutely in vain.
Slots in the beam 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. Outside, it evaporates much faster than from the middle. The resulting stress causes the material to break.
Below are the destructive factors that cause gaps in wood:
- Longitudinal cracks that run along the entire length of the product reduce its strength and can cause complete destruction of the timber.
- Gets into the openings of the part rainwater and snow. This causes dampness and rotting of the material. After a short period of time, the entire wall may be affected.
- Water that gets into 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. Such a phenomenon can lead to the destruction of all communications (heating systems, water supply) and rupture of electrical wires.
- Holes in a tree can serve as a kind of home for many insects. Ants, bark beetles, bees or wasps can settle in cavities. Few people like this neighborhood. Bark beetles can completely destroy a log house in a few years.
Thus, sealing gaps in the walls of buildings made of timber 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. And a few years before it started. If you build from dry material, then the probability of surface destruction is significantly reduced. When the humidity in all layers of the product is the same, then there will be no tension in them. Therefore, the likelihood of cracking is greatly reduced.
In order to avoid a web of cracks, the following measures are taken:
- Prolonged drying. This is necessary in order to remove moisture from the wood as much as possible. Logs should lie for 2-3 years in a cool and dark place. Their position must be rigidly fixed. This will prevent them from twisting. 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 form in undried material.
- Sealing the ends of the timber. The ends of the logs dry much faster than the rest of their surface. It has to do with the structure of the wood. As a result, the ends are covered with cracks and cracks in the first place. Through them, a plentiful exit of moisture is carried out. Such a situation can lead to deformation of the timber and a violation of the tightness of the wall. You can close 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 during the deformation of the timber will compensate for the cut. It is made 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 manual 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 changes in humidity.
But, despite all the preventive measures, cracks on the walls wooden frame cannot be avoided. it natural property wood. You can only eliminate its consequences.
How and with what it is possible to close cracks in a bar
Construction wooden houses has a thousand year history. During this long period, humanity has learned to eliminate the effects of shrinkage of wood and shrinkage of buildings. New technologies have significantly expanded the range of materials used for sealing 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.
- The use of a stub. The plug is an ordinary wood chip made to fit the hole. Hit 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 repair site is sealed with putty or a solution made from sawdust and glue.
- Seal with homemade putty. Small sawdust and PVA glue are used as ingredients. The consistency of the solution should correspond to the usual wall putty. Cavities are filled with material using rubber spatula. After it dries, the next layer is applied. After that, the surface is leveled and polished. For improvement appearance the place of repair can be tinted.
- The 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 be deformed, changing in size up to 25% of the volume, without losing specifications. At the same time, the temperature range at which the sealant can be used is from - 50º C to + 50º C. The material is placed in the cavity using glue gun. After that, the surface is leveled.
- Application of putty on wood. With the help of this material, it is possible to seal both end and longitudinal cracks. It should be noted 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 to dry surfaces. Putty is sold in a ready-to-use color form natural wood. After application, additional finishing is not required. The material is water, frost and UV resistant.
- Caulking. This is an ancient way of repairing wooden log cabins, tried and tested for centuries. To seal the cavities, ordinary moss is used, which is very abundant in the forest. The use of moss is good because this material has a very low degree of thermal conductivity. Moss seal is an additional thermal insulation. Caulking is carried out with well-soaked and pressed material. It is tightly packed into the holes with a wooden spatula. As the moss dries, it increases in volume and fills the smallest cracks. 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 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 will improve the mechanical qualities of wood, prevent it from warping, rotting 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 is supplied to the wood from the air cycle, and heat transfer is by convection.
There are 2 types of such cameras.
- Continuous duct dryers 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 resulting dried wood at home. The master determines it by mass, by eye or by sound ( dry wood ringing when tapped).
Experienced practitioners recognize the degree of moisture in 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.
Hello our dear readers. Owners of their 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 watching the appearance of more and more cracks on the walls of your still not even properly settled housing, in the construction of which, by the way, a lot of nerves, labor and funds were invested.
So the question arises: what can be done so that the timber does not crack, with what and how to process it? But is it correct? And is it really real to keep u wooden facade presentation, using only impregnations and lotions?
Why is the beam cracking?
Before you protect something and prevent something, you need to understand the very mechanisms of the problem, or all your actions, even if there are quality materials will never be effective.
So, the reason for the cracking of wood is “buried” in its uneven shrinkage. It's not a secret for anyone that after the loss of moisture, the timber noticeably loses volume. Therein lies 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 out more slowly, does not keep up with such a pace.
As a result, the tree (those very upper layers), due to the impossibility of stretching, cracks. Moreover, the more uneven the shrinkage is, the deeper and more numerous the gaps will be.
especially trouble spot in this respect are the ends of the timber. Along the cut plane, along the fibers, the tree loses moisture even faster, which means it undergoes even more cracking.
Ideally, the wood should dry evenly and very slowly so that no unnecessary stresses 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 a tree tends to absorb moisture from the surrounding air, accumulate it, and when weather conditions change, lose it again, moreover, according to the above 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 an excuse to crack.
How to extend the shelf life of a house from a bar?
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 of history 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, and most of the cracks appear on the edge of the beam, from which it is closer to the core of the material. But what does this give us?
Actually a lot. If you take this fact into account when building a house, and hide the problematic planes inside or between the crowns, the facade will remain free of defects longer, and the cracks themselves will be insignificant when they appear.
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, it is quite troublesome to follow the fibers. 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 was no other choice, they would have done so. 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 breaks when you can make a neat civilized cut?
Through it, moisture will leave the tree more evenly, and there will be no cracks. The cut will just be a little wider and that's it. Of course, such a trick will be clearly visible on open ends, and even such technical slots will have to be caulked, but it’s better than the tree itself cracking where it pleases.
Impregnation
This is how we gradually got to construction impregnations. Along with antiseptics and flame retardants, there are also such compounds 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-tight, it will simply begin to rot. But with slow evaporation, the moisture in the core gets time to rise to the surface, and therefore the tree dries out much more evenly.
In particular, often with similar paints and impregnations, the ends and joints of the timber are opened, and not at all because of cracks. Having the opportunity to remove moisture along the fibers, lumber shrinks to its edges more significantly than in the middle, and this leads to the appearance of intervent cracks, which corners are so famous for in a wooden house.
But everything has its advantages and disadvantages. Many people cannot afford colorless expensive impregnations, and in terms of their composition, the solutions are not very natural either. The cheap ones are not as effective, have a far from woody color and are often difficult to apply.
Confused?
Then let's talk about them a little more.
How to process timber
Now that we know where our legs grow from, and how all this can be solved, let's see how 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 take on the maklovitsa. 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 streaks? Agree, this protection is for the most extreme case.
Dye
You can also protect the ends with any breathable paint. Today they are on sale more than enough. But, again, the wood 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 will be minimized.
Another thing is that the coatings supplied to the market are in no way inferior in their cost to a specially designed impregnation, and most often they are much more expensive, so what's the point of reinventing the wheel then?
Wax
Another remedy that we inherited from our ancestors is beeswax. The ends sealed with it remain transparent for vapor exchange, but not for moisture. Plus, this material is of natural origin, 100% safe for human life and time-tested.
Another thing is that it is extremely inconvenient to work with such a product, it requires constant heating, and even makes the tree more susceptible to fire.
True, today manufacturers have finalized the idea of \u200b\u200bthe ancestors and created wax-based mastics that are easy to work with, 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 trademark Rogned. These compounds are pure chemistry.
But they do an excellent job of their task, are relatively cheap, easy to use and colorless. If you need a wooden texture in pure form, without a polymer can not do.
Only adherents of "green" housing will remain dissatisfied here. And this is logical. The meaning of building natural materials house, then to impregnate it with chemistry?
In a word, how to care for your log house and what impregnations or mastics for this to choose is a personal matter of the owner. It is enough to know that today there is a choice and cracking, which many perceived as a sentence, is quite realistic 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 cottage.