How much does a cube of edged boards of natural moisture weigh. The weight of a cubic meter of boards of natural moisture content of different species

What is the specific gravity of pine? The specific gravity of pine is measured in kg/m3 and is determined by the density of pine wood measured in g/cm3. Unlike many other materials, wood in particular softwood pine, is characterized not by one value of the specific gravity, but by a fairly wide range of values. The fact is that pine, like any other tree, is a porous natural material that has natural moisture. In other words, pine wood always contains a certain amount of water, which significantly affects its density, and hence the specific gravity of pine. In general, the question of what is the specific gravity of pine does not matter. practical sense, without specifying the moisture content of the wood sample. And the moisture content of pine wood can fluctuate over a wide range. Allocate, for example: the proportion of pine at natural humidity, specific gravity of freshly cut pine, specific gravity of wet, damp, wet, dried, dried, dry and absolutely dry pine wood. The quality of pine wood is reflected in the grade softwood lumber, for example: pine of the 1st grade, pine of the 2nd grade, pine of the 3rd grade. For each variety of pine, the density and specific gravity of the tree will be different. Although the determining parameter for the value of the specific gravity is still the moisture content of the wood. However, with the same moisture content of the tree, for example 12%, the specific gravity of pine grades 1, 2 and 3 will be different.

The highest specific gravity is in the growing, not yet sawn and cut down pine. This is due to the highest possible moisture content of the tree in the "growing" state. What is the specific gravity of pine in its natural state? The fact is that the natural moisture content of pine wood is not standardized in advance, as a reference parameter, but is actually determined. And it depends a lot on growing conditions. coniferous tree, as well as the season of harvesting pine wood. It can range from 29 to 81%. Accordingly, the natural specific gravity of pine can vary in the same wide range of values. From a practical point of view, specific gravity at natural moisture is usually of little interest, since it is an initial characteristic and changes rapidly. Already in the freshly cut state, the specific gravity of the pine decreases from the initial value, the one that was in the natural state “on the vine”. With all types of storage and transportation, even without special drying, pine wood loses moisture, dries and the specific gravity of pine decreases. The lowest, lowest density and lowest specific gravity of pine is in an absolutely dry state, precisely because the moisture content of such coniferous wood is very small.

In the processing of coniferous wood, the sale of pine lumber, the use of wood in construction and the manufacture of pine joinery. Of practical interest is the specific gravity of wet (moist, damp, dried) and dry pine. At the same time, despite the fact that such tree names as: wet, damp, damp pine wood are widely used by coniferous wood producers, trade organizations and woodworkers, carpenters. There is no clear specific binding of such definitions to specific values ​​of humidity in percentage terms. Dried pine is freshly sawn pine wood that has been stored for a long time under conditions in which the natural drying of the tree took place “in passing”. Its actual density and specific gravity can also be different and are not standardized by any norms and rules (SNiP, GOST). Dry pine is coniferous wood that has undergone special drying. However, for specific products and types of work, the moisture content of dry pine is determined by special requirements for these pine wood products and is regulated separately by GOST and SNiP. For example, in the manufacture of wood products and structures intended for outdoor use, dry pine is considered to be wood with a moisture content of 11 - 14%. For wooden products from pine used in residential premises, dry wood- this is wood with a moisture content: 8 - 10%. And for parquet, dry pine with moisture is used parquet board 6 - 8%. So the specific gravity of dry pine is also indicated in accordance with technological requirements to wood moisture, for specific products and types of work. Therefore, it is technically competent and correct from a technological point of view to operate with the values ​​of the specific gravity of pine using non-general terms: wet, wet, damp, dry wood. And indicate the values ​​of the specific gravity of pine only in relation to the moisture content of the tree. As additional information, it is necessary to take into account the grade of coniferous lumber: the share of pine grade 1, grade 2 and grade 3. Specific values ​​for the specific gravity of pine wood for different wood moisture (kg/m3) and the corresponding density of pine (g/cm3) can be found in Table 1.

Table 1. Pine specific gravity. Specific gravity of pine? Density values ​​at different moisture content of pine wood. See the answer in table 1. .

For the manufacture of various building materials from wood (lining, board, slats, timber), natural moisture material is used. However, according to the requirements of GOST and building codes floor board from raw wood must be dried before laying. From this indicator depends on how much the cube of the board of natural humidity weighs. Although the price of the material is charged for its volume, the weight of the board of natural moisture is important when transporting products. We will tell you how much a cube of natural moisture boards of different breeds weighs.

The concept of material moisture

Before you tell how much a natural moisture edged board and other lumber weigh, you need to understand the basic concepts. For the manufacture of grooved, terraced, planed and edged boards, different types of wood are used. Each breed has its own specific hygroscopicity, that is, the ability to absorb moisture from the air.

Depending on the absorption of moisture, porosity and the structure of cell membranes, each type of wood has its own absolute humidity. The maximum value of this indicator is 30.

In addition, a natural moisture board can absorb water in direct contact with it during precipitation or when the room is flooded. Dampness in the room is also the reason wood absorbs moisture. If the surrounding air becomes very dry, it releases moisture.

Important! Most often, moisture loss occurs through the ends of the product.

The normal process of absorbing and releasing moisture into wood is called "breathing". Equilibrium moisture is the state in which there is a balance of water between environment and inner space wood.

The indicator of natural saturation with water depends on the location of the fibers in the structure. Moisture evaporates faster in the longitudinal direction of the fibers, and not in the transverse direction. That is why the floor from the board of natural moisture quickly releases moisture at the ends of the floorboards.

To understand what is batten normal humidity, you need to understand the concept of absolute and relative humidity:

1. Relative saturation moisture is the percentage of its mass in wood to the mass of a wet product.
2. Absolute indicator always more than relative. This is a percentage of the mass of moisture in wood to the weight of ordinary dry material.

Important! Since the hygroscopic intracellular fluid collects in the cell walls, it is more difficult to remove. As a result, hygroscopic moisture more affects the geometry of the board, its weight and characteristics.

The weight of a natural moisture cut board also depends on the unbound free liquid in the material, which collects in the intercellular spaces and inside the cells. Such moisture evaporates quickly and does not affect the performance of the product.

Natural moisture refers to the moisture content of freshly sawn wood that has not been dried. This non-standardized indicator can be in the range of 30-80 percent. The weight of 1 m3 of natural moisture cut board depends on:

• conditions in which the tree grows;
• the season when the split was made (winter wood is less saturated with moisture than the one that was cut in the summer season).

The dependence of the weight of the board on moisture

If you need a board of natural moisture, the price depends on the weight of the cube of the material and its saturation with moisture:

• semi-dry products have a humidity of 18 to 23 percent;
• a raw product with a moisture content of more than 23% is the cheapest - from $ 30 per cubic meter;
• dry edged board with humidity in the range of 12-18 percent costs $40-50 per cubic meter;
• dry lumber with a humidity of 6-12 percent are the most expensive - from $ 60 per m³.

Depending on the dampness, the weight of the material also changes. For example, a cube of wet oak floorboards weighs 990 kg. If the material is dried to a moisture content of 10%, then the mass of the cube will decrease to 0.67 tons. But the price for dried lumber will increase.

The increase in price depending on the saturation with moisture is justified by the fact that the characteristics of the product also increase:

• dried wood has dimensional stability;
• it is resistant to decay;
• the material is durable and flexible;
• the tree is quickly and easily processed;
• provides a strong adhesive fixation;
• the product will last longer.

Attention! Wet wood is prone to mold, rot and warping. Ideally, if the moisture content of the lumber is brought to the point at which the shrinkage and swelling of the wood stop. That is why the cost of such products is the highest.

How much does a cube of boards from different breeds weigh?

The weight of a cube of material is directly related to the type of wood from which it is made:

1. An oak board of natural moisture content weighs 990 c/m³. A cube of dried wood weighs 670 centners.
2. Wet pine floorboards weigh 820 kg / cu. The dried elements have a weight of 470 c/m³.
3. Cube boards from wet spruce wood weighs 760 q, and dried board - 420 q.
4. Wet larch products have a weight of 940 kg / cu. A cube of dry larch weighs 630 kg.
5. birch lumber undried weigh 870 centners / m³, and dry - 600 centners / cu.
6. Aspen floorboards from wet wood - 760 centners / cubic meter, and dried - 470 centners.
7. Alder wood cube after saw cut, it has a weight of 810 centners, and the dried material - 490 centners.

Why is it necessary to know the weight of a cubic meter of wood?

Since the manufacturer charges the price for lumber depending on the type of wood, moisture content and volume, the weight of the material is not taken into account. This indicator will be needed when transporting lumber, since the choice depends on it. vehicle and the cost of transportation.

Also, the weight of wood is taken into account when calculating the loads on building construction. As a rule, an ordinary consumer does not need such a calculation. It is made by designers and designers at the stage of project development.

Artificial and natural drying

Natural drying of lumber is very slow and stretches for a long time. However, such a drying process is considered the most gentle, since cracks and other deformation defects do not appear in the wood. With aggressive chamber drying, there is a high probability of cracking and deformation of the lumber.

Important! Natural drying is carried out in a special well-ventilated place, which is reliably protected from atmospheric moisture and direct sunlight.

Humidity of a freshly cut tree reaches 50-80%. With natural drying, this figure drops to 18-22 percent. This drying method is the easiest to organize, since it does not require the use of special equipment and adherence to a certain temperature regime. The disadvantages of natural drying are the duration of the process and low intensity.

Artificial drying in chambers proceeds much faster. At the same time, the humidity index decreases to 10-18 percent. During the drying process, you can adjust the temperature and control the whole process. Products placed in stacks are placed in the chambers, each of which contains sawn timber of the same thickness and breed.

Advantages of artificial drying:

• protection against mold and rot;
• you can dry wood treated with special protective compounds;
• drying speed (usually it takes a week).

The wood has been used in construction works ah from a long time ago. Of course, because this material is still very popular due to the presence of excellent specifications. Wood itself is natural material structured type, consisting of wood cells and pericellular voids, which in turn does not guarantee at all that one part of the wood will be equal to another of identical size. Therefore, so often, in the process of work, the question arises of counting the right amount this material and such parameters as: the weight of the wood as a whole and the weight of the cube of wood.

Depending on the type of construction work, it is necessary to measure wood in different ways. On the weight of m3 of wood, the density of the material is of particular importance, respectively, for right decision of the questions posed, it is necessary to determine the value of the density. There are two types of density:

Specific gravity (density of the wood substance)

Volumetric weight (density of a structured physical body)

Wood substance is a mass of solid wood materials without natural voids. This type density is measured in laboratory conditions, as it requires additional measurements that are not feasible in normal conditions. For each wood of all types and species of trees, this value is a constant and is 1540 kg/m3.

The density of the wood itself is quite easy to determine under normal conditions. To do this, just weigh a piece of wood and measure its volume. Process the obtained data with standard arithmetic operations according to the following formula: Y \u003d M / O, where Y is the specific weight of the tree, M is the mass of wood, O is the volume occupied.

Table of volumetric weight of 1m3 of wood depending on humidity.

The density of the wood substance, as already mentioned, is a constant. However, wood has a multicellular fibrous structure. complex type. The walls of the wood substance play the role of a frame in the wood structure. Accordingly, for each breed and species of trees, the cell structures, shapes and sizes of cells vary, as a result of which the specific gravity of the tree will be different, as well as the different weight m3 of the tree.

Also, humidity plays an important role in changing the specific gravity of wood. Due to the structure of this material, with an increase in humidity, the density of wood also increases. However, the density of the wood substance this rule does not apply.

Below is the specific gravity of wood. The table is compiled depending on the moisture content of the material and is calculated such an indicator as the weight of 1 m3 of wood.

When working with lumber, it is often necessary to know what mass of wood. Let's figure out how much a cube of wood weighs and how to determine this value?

The mass of wood - why measure it?

First, let's figure out why this value is needed at all - mass of wood and how important this indicator is.
The weight of wood plays a big role in construction:
- Firstly, this indicator makes it possible to determine the weight of the finished structure, whether the floor or foundation will withstand it;
- secondly, a specific mass of lumber is necessary when determining the method of transportation, it helps to determine how much transport can move a particular amount of wood;
- thirdly, before buying a material, you need to figure out how much a cube of timber weighs, how much a cube of lining or boards weighs. All these materials are not sold individually, but in cubic meters. Therefore, knowing how to determine the weight of the material is necessary at least so that unscrupulous sellers cannot deceive you. Well, in order to provide for yourself necessary quantity material doesn't hurt either. To find yourself in a situation where at the most inopportune moment you realize that there is not enough material is rather unpleasant, just like the situation when, after the completion of construction, it turns out that there is still a whole trailer of wood that is no longer needed;
- fourthly, such an indicator as mass of wood important in determining where to store the material. Knowing how much wood occupies, you can easily determine what size storage room you need.

How to determine the weight of a cube of wood?

The mass of wood depends on several parameters:

The type of tree. Wood species are divided into light ones weighing up to 500 kilograms (this includes conifers), medium - weight up to 650 kilograms (for example, birch or ash) and heavy - weight over 700 kilograms (the most popular representative is oak).

The humidity level is also divided into several levels: dry wood - humidity up to 15%, air-dry - humidity up to 20%, raw - up to 45%, and wet - humidity above 46%. That is, at different humidity, even the wood of one tree will have a different mass and weight different breeds will be different even with the same humidity level.
The very concept of wood mass includes several measured parameters that are convenient to use in a particular case:
- The specific gravity of wood is a parameter that shows how the cube of wood and the cube of water correlate. The specific gravity of lumber is determined without taking into account moisture and wood species, that is, this indicator will be averaged for any tree. Specific gravity is used both to determine the actual cubic capacity of the wood and to determine the volume of the stocked board. Specific gravity wood is convenient to use for companies involved in the transportation of material, in which case it is not necessary to measure the humidity and other values ​​​​for each individual species, because sometimes several species of wood are transported, and their humidity can be completely different, calculation total weight such materials will take a lot of time, therefore it is easier to use a ready-made average value.
- void ratio - this indicator, which helps to determine the mass of stored lumber. Stored wood, especially if it is unfinished or has a non-standard shape, forms voids among themselves, which significantly affect the determination of the total mass of such material. If the void factor is not taken into account in the calculations, only very approximate values ​​\u200b\u200bcan be obtained. What is the formula for calculating the weight of wood, taking into account the coefficient of voidness? If we take all the stored material as 100%, then about 20% of them will occupy voids, respectively, the remaining 80% is wood. The void ratio will be 0.8. Let's say you have 10 cubic meters of space occupied by a stored board, multiply 10 by a factor of 0.8 and we get that the wood in the room is 8 cubic meters.

Reference values ​​​​are on the Internet, and simply in everyday life there are certain persistent values ​​\u200b\u200bof the weight of wood and wood products. This value is easy to use when buying. It is enough just to know the type of wood from which, for example, lining is made. You open the table and see how much one cubic meter of lining made of alder or oak timber weighs. This makes it very easy to check whether lumber sellers are deceiving you.

Volumetric weight of a cube of wood - an indicator of volumetric weight is often equal to the values ​​​​of the density of wood. To determine it, a universal indicator of humidity is taken - 20% and a fixed density value is determined. All measured data are entered into special tables and are freely available on the Internet. Volumetric weight is also called GOST. The volumetric weight of wood uses the definitions of the parameters of both the raw board and the raw board. This value is very universal and allows you to compare the weight various breeds, but subject to the same humidity.

Weight of a cubic meter of wood of different moisture content

Below is a table that shows the weight values ​​of wood of different species at different levels of humidity.

Irina Zheleznyak, Correspondent of the online publication "AtmWood. Wood-Industrial Bulletin"

The weight of lumber has an impact on transportation and storage. When erecting wooden structures weight is also important in determining the loads being transferred to the load-bearing members or foundation. However, when selling lumber, it is measured in cubic meters, which causes difficulties.

What affects the weight of lumber?

Consider the factors affecting weight wooden materials given volume:

wood species. This factor determines the density of the material, since wood of the same species is characterized by similar density values. This indicator already directly affects the weight - the denser the material, the heavier. Average, deciduous trees denser than conifers, so the cube oak board heavier than a cubic meter of pine board.

So, in front of you is a board cube - how much does this or that breed weigh? The weight of wood per cubic meter of lumber is given in the table (kg).

Humidity. Wood is characterized by the ability to accumulate moisture. There are two options here: the board is poorly dried, and retained its natural moisture, or was stored in improper conditions. The higher the moisture content of lumber, the heavier it will be. Therefore, even the same breeds weigh differently. This, by the way, is a way to identify materials stored in poor conditions or poorly dried.

The use of such components in construction is fraught with negative consequences, of which strong shrinkage is not the worst.

It is also unreasonable to use such a board in construction.

Internal defects. Similar to the previous point, internal defects in wood lead to a decrease in density and weight loss.

Artificial and natural drying

Ideally, lumber should dry naturally, i.e. in a ventilated room with a roof or on outdoors under a canopy.

Since dry lumber is more in demand than natural moisture material, accelerated drying methods are used. The question of how safe this is for the material remains debatable. It is believed that artificial drying leads to too rapid evaporation of moisture, which causes a change in the geometric dimensions of the boards. Due to microscopic damage to the fibers, curvature and irregularities are formed. In especially advanced cases, cracks appear.

However, drying with the use of forced air, including warm air performed without fanaticism is unlikely to lead to such obvious negative consequences.

Wood moisture should be taken into account when arranging transportation. Let's say you bought dry boards, but during storage they were exposed to rain and did not completely dry out. Their weight, of course, will no longer be the same as when delivered.