How many crowns are in the log house. Calculation of the amount of materials for a house made of logs. Builders' mistakes: typical and gross
A wooden house is a house made of living material - wood. Wood has many advantages, including environmental friendliness, sophisticated look and easy installation. It will fill your home with a pleasant forest aroma and create a cozy atmosphere. In such a house it will be cool in summer and warm in winter. Therefore, many owners of suburban areas prefer to build a cottage or country house from wood.
In spite of a large number of positive properties, such a house has one drawback. This is shrinkage. However, if you know the principles of the formation of this process, then the problem is easy to deal with.
LOG HEIGHT
A log house consists of crowns that are stacked on top of each other. Each crown of a particular log diameter has its own height. It depends on the thickness of the log.
For example, in a log with a diameter of 200 mm, the height of the crown is 170 mm, and 30 mm goes to the longitudinal (lunar) groove of the log. It turns out that the lower log is buried in the upper one to a depth of 30 mm. The remaining 170 are the useful height of one crown.
For a diameter of 220 mm, the useful height will be 190 mm, for 240 mm - 210 and so on. By the way, if you are building a house for permanent residence, then a log with a diameter of 240 mm - best option for central Russia. In such housing it will be warm and comfortable even in the cold winter.
Thus, in each log of any diameter, the lower one is buried in the upper one by 30 mm. Knowing this value, it is easy to calculate how many crowns are needed for the desired height of the log house.
HOW SHRINKING HAPPENS
During construction country house logs of natural moisture are used, since only such materials can be processed on equipment without damaging the processing knives. In addition, the logs dry out as part of an already assembled log house. This is the only way to achieve the hitch of logs, which are pulled together by natural forces into a single structure. The house becomes an integral object.
Each crown of the house consists of a tree trunk, and each tree trunk releases (evaporates) moisture over time. As a result, it becomes dry and shrinks across the fibers. Thus, the compression occurs vertically. Horizontal drying (along the fibers) practically does not occur due to the structural features of the tree.
When shrinking, the house gradually dries up and loses a little in height. Each crown in the composition of the house dries up and loses 3-5% of its thickness. As a result, the whole house can also lose 3% - 5% in height, regardless of how many crowns are in the composition.
Shrinkage of a wooden house is an endless process, but there is nothing to be afraid of. The active part of the process takes place in the first 6 months after construction. Then the house also shrinks, but only slightly. This is an inconspicuous action that will not affect the structure of the house, interior and exterior finishes.
Shrinkage of the house proceeds in a decreasing exponential manner, where the most active part falls on the first six months.
The slower the shrinkage process, the better. This reduces the risk of cracks in the walls, since the logs do not experience a sharp change in humidity, and evaporation is slow. The main part of the moisture from the log leaves through the ends. To clog the ends, a special compound is applied that slows down the release of moisture and reduces the number of cracks.
This will help you avoid trouble. For example, such as creaking doors or poor closing of windows. Therefore, it is important that construction and finishing work is carried out by experienced specialists using special technologies and certain types of fasteners. You will learn about these technologies and fasteners in the next newsletter.
The main mistakes in the construction of chopped wooden houses.
Chopped houses faithfully serve people for more than one millennium. Houses made of solid wood give their owners the incomparable pleasure of living in a comfortable microenvironment. Solid wood has a high heat capacity (2.4 times higher than that of ceramic bricks), which makes it possible to smooth out daily temperature fluctuations. Also, the porous structure of the tree allows you to naturally regulate the humidity in the room due to the cycles of absorption and evaporation of moisture. The frame is relatively resistant to soil and foundation movements. The wooden surface often does not require any additional processing, except for grinding and coating with antiseptics to create beautiful interiors.
However, only correctly cut down trees will give comfort to their owners. wooden houses. The construction of a log house requires high carpentry skills at the level of 6th category. Without experience and qualifications, it is almost impossible to cut down wooden house no mistakes. And mistakes during construction can negate all the advantages of a log house. Houses built with mistakes are easy to recognize: builders or owners have to additionally insulate and sheathe them from the outside and inside to hide defects, eliminate through blowing of locks in the corners and interventional seams. One of modern options houses made of solid wood, practically devoid of the disadvantages of log cabins, are houses made of glued beams. Thanks to the features of this technology, blowing through the seams and cracking wood in such houses is practically impossible.
In this article, we will briefly touch on the most common mistakes in the construction of log houses.
- Log preparation errors.
Mistakes in the choice of material for construction.
According to GOST 9463-88 "Round timber conifers» pine, spruce, fir and larch round timber is suitable for building houses. Larch is the most expensive material, the hardest and most resistant to decay. Spruce has a lower density, excessive knotting and is prone to more cracking. The optimal tree for building a house is a pine aged from 80 to 120 (140) years old, grown in the northern regions (Arkhangelsk, Angarsk, in Karelia) on dry sandy soil, at least 24 meters high. The best pine logs have a dark red or yellow-red core, indicating a high density of wood. More loose varieties have a pale yellow core. The forest of winter felling, contrary to folk legends, actually has more high humidity sapwood (25-50% higher than in summer), more starch and, therefore, more easily affected by fungi. It is possible to determine the round timber of winter felling using a qualitative test for starch: a stroke is applied to the debarked wood with an iodine pencil. If the stroke turns blue - in front of you is a tree cut down in winter.
For construction, it is allowed (this does not mean that you must agree to the purchase of such materials) timber with such defects as mushroom blue and colored sap stains (no more than 1/20 - 1/10 of the end diameter), wormholes (no more than 5-10 pieces per 1 running meter), lateral cracks from shrinkage no more than 1/20 -1/5 of the end diameter, trunk curvature no more than 1-2% (1-2 cm per 1 running meter). Logs used for construction must have a run-off value (thinning of the log to the top) of no more than 0.8 cm per 1 m of length.
Rot (sapwood, rotten, sound) and tobacco knots (decayed knots of brown or white color, crumbling under load) are not allowed in round timber.
The minimum diameter of round timber for a residential building is 22-24 cm. The width of the grooves should be at least half the diameter of the log, and in the northern regions it can be increased even more. With a smaller size of the grooves, the consumption of timber decreases, but the thickness of the interventional seams becomes smaller, and the house becomes more “cold”.
The cutting of corners can be carried out without residue "in the paw" or with the remainder - "in the corner". Cutting "into a corner" makes the connections more reliable, and the log house more stable. In addition, the wood allowance better protects the castle from the effects of atmospheric factors. The cutting "in the paw" is usually used for the subsequent sheathing of corners or the entire log house. For residential buildings, the device for connecting logs in the corners must have internal locking elements that exclude the through blowing of the corner (connecting logs “in a bowl” with a barrier or “in a cloud” with a barrier). Due to its geometry (inverted bowl), cutting "in the cloud" allows better removal of moisture and faster drying of the joint. Cutting internal locking elements requires a highly skilled carpenter, such work takes more time and costs more. Otherwise, the corners of the residential building will be protected from blowing only with tow ( heat-insulating material). This is one of the main disadvantages of round log houses, where log joints are manufactured industrially without additional internal locking elements.
Moisture content of timber for construction. SP 64.13330.2011 " wooden structures» allows the use of raw solid wood for the construction of houses with a moisture content of up to 40% under the following conditions: the predicted shrinkage of the wood should not violate the structure and flexibility of the joints, and the timber itself should be subjected to antiseptic treatment and conditions for drying out and protection from moisture should be provided for them . It is optimal if the log house dries out, installed in place on the foundation and under the roof. Drying period from 6 months to 1 year. If the log house stood at the seller in the feet (separate parts of the log house with 5 crowns, convenient in height for processing) without a roof for 6-12 months, then with a high probability this means that the tree will be affected by rot. It is permissible to purchase log cabins that have stood under the roof.
It is important to understand that the higher the humidity of the timber, the greater the shrinkage of the tree, and the wider the gaps between the crowns, the gaps in the corner joints (especially with cutting defects), the more the tree will crack.
Why don't they cut down houses from dry wood? Dry wood has a greater density and hardness, and is much more difficult to process. The rounded log is subjected to chamber drying upon request after processing. However, kiln-dried wood can warp as the equilibrium moisture builds up on the construction site. They use Finnish and Karelian dry pine of equilibrium moisture in construction, but this is already an exclusive product. In addition, a properly assembled frame made of raw wood, during drying in the assembled state, “sits down” in place, reducing the size of the through slots and, accordingly, the coefficient of blowing through the walls. It is important to know that it is possible to paint (do not mean antiseptic treatment) wood only if its moisture content does not exceed 15%. Otherwise, the wood will crack badly when it dries. Therefore, the processing of log cabins is permissible only with vapor-permeable antiseptics. Treating a damp (damp) log house with a vapor-tight antiseptic will also cause the wood to crack as it dries.
For pins (dowels), only dry (no more than 12%) straight-grained wood without knots should be used. Birch pins must be antiseptic.
Fastening logs to metal elements (reinforcement trimmings, long nails) is not recommended, since moisture accumulates on the media section, and metal elements become centers of biological destruction of wood. Usually, rebar is used by unscrupulous builders to fasten and "tighten" crooked logs, which then leads to a violation of the normal shrinkage of the log house, the formation of cracks and the bulging of individual logs. It is strictly forbidden to pierce with nails corner connections logs, as this will interfere with the movement of the tree during shrinkage, and will contribute to the formation of cracks (nails after shrinkage of the tree will rise above the surfaces).
Types of timber processing for construction.
The most traditional for Russia is round timber. In Scandinavia, a carriage is used (from the Norwegian "lafteverk" - log cabin) - logs hewn from two opposite sides into two edges, or a semi-carriage - logs hewn one edge from the inside. The cost of a hewn log can be 35-50% higher than a round log. When processing round timber, builders sometimes leave parts of the bast (podkore) not removed. According to the norms, no more than 20% of the bast can remain on the round timber. However, it is better to remove the bast completely by shaving (planing), as the bast contains many polysaccharides, which are an excellent breeding ground for microorganisms and insects that can damage the wood. Also, when guarding, young layers of sapwood that are less resistant to damage by fungi and insects are removed.
Waterproofing must be laid between the first flashing crown and the foundation. Until now, for some reason, builders use for waterproofing a short-lived material based on cardboard - roofing material, in which through holes and cracks are formed in 7-10 years. For waterproofing, it is necessary to use modern bitumen-polymer materials with a service life of 25-50 years. Of course, the complete absence of waterproofing is also unacceptable. The use of a backing board under the flashing crown reduces heat losses by heat transfer from the frame to the foundation, reduces the risks of biological destruction of the flashing crown. According to the requirements of SP 64.13330.2011 "Wooden structures", such wooden linings (pillows) should be made of preservative wood mainly hardwood(oak, aspen). If necessary, backing boards can be replaced with new ones. Replacing the crown crown is a much more time-consuming procedure. The lower crowns of the house must be protected from moisture. The greatest harm is caused by rain splashes reflected from the ground and snow rolled against the wall. To protect the logs from splashes and snow, it is recommended to raise the foundation above the planning mark by at least 40-50 cm.
Additional protection factors for the log house include splash-proof visors protruding above the plinth, long roof overhangs (75-120 cm) and equipping the roofs with gutters and pipes.
Orientation of logs when laying. Every tree has a natural curvature due to wind loads during tree growth. When laying logs, they will certainly be laid with the curvature upwards so that the loads from the overlying structures compensate for the bending of the wood. If you do not follow this principle, then the logs will stick out to the sides. Normally, the deviation of the crowns of chopped walls from the horizontal per 1 m of length should not exceed 3 mm.
The size of the interventional gaps should not exceed 1 mm. With the Russian felling system, it is quite difficult to fulfill this condition, since as the tree dries out, the cracks open up. The advantage is the Norwegian felling system with a wedged longitudinal groove and a sliding self-jamming lock, in which, as the tree dries out, the logs shrink relative to each other, reducing the size of the intervents cracks.
In Russia, traditionally, they continue to insulate the interventional gaps of log houses with natural materials such as flax, jute, felt, moss, etc., which are not elastic, are subject to biological destruction, and are a breeding ground for microorganisms and insects. All of these materials require repeated caulking. Meanwhile, in Scandinavia, an elastic self-expanding polyethylene foam tape is used as an interventional sealant, the use of which eliminates the need for repeated caulking.
If possible, you should avoid connecting logs in crowns along the length. Such connections weaken the structure of the log house, and the walls of the log house can be deformed. The logs used in the construction should be as solid as possible. And it is definitely not worth making connections at the intersections of the walls, where load concentrations occur.
Shrinkage and swelling of wood along the fibers are manifested to a greater extent than across the fibers. Therefore, all vertical racks and columns must be equipped with shrinkage compensator platforms, which are tightened to the required shrinkage value, which can last up to 6-8 or more years. Perhaps a more aesthetic option is to install expansion joints at the bottom of the columns, where they are less visible.
It is not recommended to cut openings for windows and doors in the frame before the end of the first active period drying of wood (6-12 months). During the same period, you should not hem the floor, ceiling and sheathe the walls, as this will interfere with normal ventilation and drying of the wood.
Particular attention should be paid to the ventilation of the underground space during the device wooden floors. The minimum cross-sectional area of one vent should be at least 0.05 m 2, and the total area of the vents should be at least 1/400 of the underground area. It should be noted that this design of floors is already archaic. In the world, floors are mainly used on the ground, which allow you to use geothermal, avoid problems with humidity in the underground space and the flow of radioactive soil gases into the house.
3. Mistakes in finishing a log house.
When installing window and doorways we should remember that the minimum distance between the openings is 90 cm. The walls must be reinforced with dowels. For installation in log houses, it is better to use windows and doors with frames at least 10 cm wide, which does not allow the window and door block to be deformed during the secondary caulking of the house.
The fastening of the bars for the frames of doors and windows should be sliding - without the use of nails, since the shrinkage of a wooden house can last quite a long time. Above windows and doors, compensation gaps are left under the top log for shrinkage of 5-8% of the opening height.
It is better to use self-expanding elastic sealing tapes for sealing window and door frames. Plain polyurethane foam when expanding, it can deform window frames, and when the tree shrinks, it can form cracks. If it is used, then after hardening it should be covered from the outside from exposure to the sun and moisture with a waterproofing vapor-permeable self-adhesive butyl rubber tape. From the inside, the foam must be covered with a vapor barrier tape. Unprotected foam quickly breaks down, as in the house in the photo below.Finishing the interventional seams of the assembled log house after the end of the first stage of intensive drying (12-24 months) with glazing beads or a rope is only decorative, contributing to the waste of money and time, but not protecting the walls from blowing. Modern elastic and vapor-permeable interventional sealants (for example, from the domestic manufacturer SAZI) make it possible to protect interventional cracks from blowing through and create an aesthetic appearance walls.
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External insulation of a wooden house. Most often, external insulation has to be resorted to when construction defects are detected, such as through blowing through walls. The main and most critical mistake is the external insulation of a wooden house with vapor-tight heaters (polystyrene foam, polyethylene foam). In this case, the tree is deprived of the opportunity to dry out, it is moistened, which increases its thermal conductivity and accelerates biological destruction. In clause 8.8 of SP 23-101-2004 "Design of thermal protection of buildings" it is prescribed to arrange the layers of multilayer walls in such a way that the vapor permeability of materials from the inside to the outside of the heated house increases, and does not decrease.
Aesthetics of a wooden house. Often, lovers of wooden houses, where all the elements of the interior, such as walls, floors, ceilings, beams, railings, furniture are made of wood, find that, perhaps, they went a little too far with the number of wooden surfaces that create the feeling of living in " wooden box". To the rescue comes the change of furniture and the painting of the walls. However, it is wiser to plan contrasting surfaces in the house at the design stage. These can be floors, ceilings, countertop surfaces in the kitchen, steel elements of stairs and railings, decorative wall from natural or artificial stone.
-> Do-it-yourself log house -> Log house design"Bricks of the log house" - crowns.
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The peculiarity of any tree is that its trunk grows unevenly in thickness: more on the south side, less on the north. Therefore, the annual rings on the south side are wider than on the north. For an example (Annual rings of a tree), I specifically chose a tree that grew on the southern edge and the difference in the thickness of the sides is clearly expressed. In the crown of the log house, the logs are stacked so that the side of the log, where the annual rings are denser (the northern side), looks out. The north side cracks less. And the southern one, due to its lower density, is a little warmer. However, this is only possible if the forest is drill (flat). If the log is curved, then it is laid on the wall of the log house, regardless of the orientation of the annual rings, either with a hump up or a hump down. If there are a lot of crooked logs and their curvature is approximately the same, then one wall can be made slightly crooked by laying the logs with a hump outward. In the finished frame, the curvature of the wall is almost not noticeable. |
For reliable thermal insulation and windproof walls, between the logs, in the process of laying the crowns, is placed interventional sealant. I am an ardent supporter of such a compactor as moss- unique in its properties natural material. For more information about its advantages, harvesting, storage and laying on logs, see the topic “Moss. Log cabin caulking»
Basic principles of assembling a log house.
1. Layout of logs in the crown.
2. Vertical fastening of logs.
In order for the structure of the log house to turn out to be rigid, so that over time the walls do not swell in a vertical plane (especially in the area of door and window openings), when assembling the log house, vertical rallying of logs with dowels is used (in Belarus they are called dowels).
Nagel (dowel) is a round or quadrangular wooden stick that is driven into a hole drilled immediately in 2 - 3 logs in height. Any wood can be used as a material for dowels. Nagels are inserted into each crown.
Under no circumstances should metal pins be used as dowels!
On metal pins in the cold season, moisture will condense from the air passing through the interventional seal. The joints will be constantly wet, which will be a prerequisite for the development of decay processes inside the walls.
Sometimes builders, for the vertical rallying of logs, drive pointed metal pins into the crest of the upper log with a sledgehammer. Under no circumstances should this be done!, since the clogged pins prevent the free shrinkage of the logs and they hang on the pins. As the logs dry out, the intervent gaps increase.
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At the end of the assembly of the log house, for aesthetics, we make the protrusions of the edges of the logs in the corners the same. For this: we measure on the upper log such a distance from the corner to the end that suits us (but not less than 20 cm). Then, attaching a plumb line to this mark, we draw marks with a marker on all the bottom lying logs. With a chainsaw, we cut the ends of the logs strictly vertically (according to our markings). Since the fibers at the ends of the logs remain open, the ends of the logs will dry faster than the middle of the log. And, in this regard, large cracks will appear at the ends. In order to minimize cracking, I recommend covering the ends of the logs with acrylic varnish for outdoor use or PVA glue. In the old days, the ends of the log cabins were covered with clay, lime mortar or painted with paint. |
When felling a log house openings for windows can be omitted or made deliberately smaller in size. Later, when we install windows, openings are cut with a chainsaw to a specific size, taking into account the landing spike.
If you are faced with the task of finding a supplier of construction services if you want to build a wooden house or a bathhouse, then it is inseparably linked with the concept that involves the calculation of a log house. Having calculated the quantity required material, you can find out what its cost is for 1 m 3. This will be the actual cost of the kit. Here, each owner of the territory for building is trying to understand what the cubic capacity of the building is made up of.
In order to independently calculate the volume of the bars in the house, it is necessary to use the specified parameters as the main ones, namely: heights and axial dimensions. This will allow you to calculate the linear meters of the bars in the house. The easiest way is to multiply the length in linear meters in the crown by the number of crowns.
Determining the number of crowns and calculating the material
In order to calculate the required number of crowns for a round log building, you need to know what the working height of the log is.
Figure 1. Characteristics and dimensions of round logs.
It depends on how wide the groove of the beam has. Rice. 1 illustrates a table that can be applied to a standard slot. If you divide the height of the beam by the working height of the beam, you can get the number of crowns needed for work.
For example, you can calculate the volume of beams for a house, the dimensions of which are 6x9 m. The example assumes that it is necessary to make calculations for a log house, the height of which is 3 m.
The task is to calculate the number of crowns in the house from rounded logs, the diameter of which is 220 mm. To do this, 3000 mm must be divided by 191 mm, which will be equivalent to 15.71 mm. This suggests that for a given height, 16 crowns will be needed.
Using the data indicated in the drawing of a log house, you can determine how many running meters are in one crown. Do not forget about the protrusions that represent the corners.
In this example, the crown length is calculated as follows: 9+9+6+6+6, which is equivalent to 42 running meters. This suggests that you can calculate the running meters in the house from the example as follows: 42x16, which will be equal to 672. After that, you have to take into account the halves of the zero crown, the data of which also needs to be added, they are needed to shift the rows.
The halves are calculated as follows: 3x6, which is equivalent to 18 running meters. For the reason that one solid beam is needed to obtain 2 halves, it is necessary to divide 18 by 2, you get 9 linear meters of beams in halves.
In the end, we managed to get 681 linear meters, but openings were not taken into account here. If you subtract the running meters of openings, you can get 546 running meters.
After that comes the turn of the calculation, of which the log house consists. This must be done using the formula: π * r ^ 2 * l (here π is 3.14; r is the radius of the beam; but l is the length or number of linear meters in the house). The calculation itself is as follows: 3.14x0.11x.011x546, which is equal to 20.75 m 3. This means that the volume of the log that makes up the log house in this example is 20.75 m 3.
Do not forget about illiquid residues, as well as losses in the process of sawing the parts of the building kit. This number can be equal to the limit of 3-7 percent. This suggests that the test cubic capacity of the building from the example will be about 22 m 3.
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The cost of the material of the house kit
If we take into account that the price of 1 m 3 of a log of a set is 8.5 thousand rubles, then the cost of this log house from a log will be 187,000 rubles.
Such a price is not only lower than that presented by developers working with stone and brick, but is also justified in many respects. First of all, in a dwelling built of wood, natural air exchange will take place through the walls, the volume of which per day is approximately equal to 20% of the total air volume in the premises, which is true even with closed windows and doors.
This will allow maintaining in the rooms the most suitable balance of oxygen for a person, with regard to humidity and thermal indicators. It is worth considering that in order to maintain normal vital signs, it will not be necessary to operate climate systems. In such a dwelling, you will be warmer, because wood has a slight thermal conductivity.
When comparing brick and wooden walls, the latter will surpass the former in terms of thermal insulation characteristics. The same ratio of thermal conductivity can be achieved with a wood wall thickness of 10 cm and a brick wall of 51 cm. These examples can be considered more than illustrative.
If you decide to build a log house, and use a rounded log as a material, then you are already familiar with all the features of the calculation. Now it only remains to choose the most profitable service provider by comparing the cost of a log house that each of them offers to its consumers. It is important and correct to choose a rounded log, and this issue will have to be approached with no less seriousness.
Wood is a unique natural building material that has a large number of positive properties and has a huge number of fans. Thanks to this, wooden houses have not lost their popularity even after the appearance on the market of new inexpensive building materials with good quality characteristics. Moreover, with the beginning of the use of milling machines for rounding logs and obtaining a beautiful, high-quality and easy-to-lay material, the demand curve for structures (houses, baths, cottages, etc.) made of wood went up sharply. Today, rounded logs are as common in construction as gas silicate blocks, sandwich panels or bricks.