Getting ready for construction frame house, erecting the roof and assembling the crowns of the log house, the developer has to purchase timber.
This material is used for the manufacture of various wooden structures, so its range includes dozens of items. To eliminate errors, you need to determine as accurately as possible how much timber is in a cubic meter.
The “mathematical model” of this operation is simple. To calculate the volume of any rectangular object, its length is multiplied by its width and height. However, in practice, when purchasing large quantity timber different lengths and sections, you can get confused and overpay a considerable amount.
In this article we will talk about the important nuances of calculating the volume of lumber and provide easy-to-use “cheat sheets” for translation linear meters lumber into cubes.
Be careful at the timber warehouse!
Considering high cost edged timber, its purchase must be taken responsibly. Sellers, as a rule, use the price per 1 m3. Customers at checkout rafter system roofs, wall frames, floor beams and floors receive linear meters. Additional confusion is caused by production length standards, which range from 3 to 6 meters (0.5 meter increments).
It’s not difficult to sort everything out in this matter. Let's say that for construction you need a beam with a cross-section of 100x50 mm, and its total length is 100 linear meters (l/m). To calculate the volume of edged wood, you need to convert the cross-sectional area from millimeters to square meters and then multiply them by the length: 0.1x0.05x100 = 0.50 m3. We get the price of a given amount of timber by multiplying its volume by the cost of one cubic meter.
And here’s another equally important question: how to control the amount of lumber that the seller gives you? Here you need to take into account not only the cross-section, but also the length of the material.
Let's say that we need a beam 4 meters long (total length 100 l/m). In this case, the volume of one piece will be equal to: 0.1x0.05x4 = 0.02 m3. Dividing the purchased amount of material (0.5 m3) by the volume of one bar (0.02 m3) we get exactly 25 pieces.
In practice, round numbers are rare, so the required amount of timber is most often a fraction. We will not give to the seller that part of the lumber that remains after the comma. It’s better to pay him up to a whole number of beams.
Let's look at an example. 63 linear meters of timber are purchased (section 100x180 mm, length 6 meters). We calculate the purchase volume: 63x0.1x0.18 = 1.134 m3. We divide it by the volume of one beam (0.1x0.18x6 m/p = 0.108 m3). We get 1.134/0.108 = 10.5 pieces. The seller will not cut half of the timber for us. Therefore, when calculating, you need to pay him up to the whole amount and take 11 beams.
With profiled timber, the cross-section of which is complex shape, do the same as with the usual one. To determine the cross-sectional area of this material its total height (the distance from the bottom edge with the groove to the top mark of the tenon) is multiplied by the width.
Counting the amount of timber in the warehouse in 1 m3, take a tape measure and measure the actual cross-section of the purchased material. It may turn out that instead of the 100x200 or 150x150 mm promised by the seller, they delivered more thin material. Even a 1 centimeter reduction in the transverse size of a saw log results in significant losses for the buyer.
Another important nuance– technological deviation of beam length. It can reach 5-7 centimeters, since the ends of the logs are not cut off during processing. Remember that the seller does not have the right to add these extra centimeters to the total length.
Tables for quickly calculating the volume of timber
Using a calculator to count how many pieces of timber are in a cube is not always convenient, especially when purchasing a large batch. The seller's data can be easily controlled using ready-made tables. Here for standard sizes lumber provides information on the volume of 1 timber and the number of pieces in 1m3.
Table for calculating edged timber 6 meters long
| Dimensions (mm) | Volume of 1 piece (m3) | Pieces per 1 m3 |
| 100x100x6000 | 0,06 | 16 |
| 100x150x6000 | 0,09 | 11 |
| 100x180x6000 | 0,108 | 9 |
| 100x200x6000 | 0,12 | 8 |
| 150x150x6000 | 0,135 | 7 |
| 150x180x6000 | 0,162 | 6 |
| 150x200x6000 | 0,18 | 5,5 |
| 180x180x6000 | 0,1944 | 5 |
| 180x200x6000 | 0,216 | 4,5 |
| 200x200x6000 | 0,24 | 4 |
| 250x200x6000 | 0,3 | 3 |
This table can also be used when purchasing 3 meter timber. To do this, the volume of 1 piece must be reduced by half, and the amount of material in one cube must be multiplied by 2.
Let us recall that timber, by definition, is lumber with a thickness and width of 100 mm or more. Therefore, we deliberately did not include sizes in the table. wooden blanks smaller cross-section to maintain formal accuracy.
Let's look at the data on the volume and number of boards of common sizes in a separate table:
| Dimensions (mm) | Volume of 1 piece (m3) | Pieces per 1 m3 |
| 25x100x6000 | 0,015 | 66,6 |
| 25x150x6000 | 0,0225 | 44,4 |
| 25x200x6000 | 0,03 | 33,3 |
| 40x100x6000 | 0,024 | 41,6 |
| 40x150x6000 | 0,036 | 27,7 |
| 40x200x6000 | 0,048 | 20,8 |
| 50x50x6000 | 0,015 | 66,6 |
| 50x100x6000 | 0,03 | 33,3 |
| 50x150x6000 | 0,045 | 22,2 |
| 50x200x6000 | 0,06 | 16,6 |
| 50x250x6000 | 0,075 | 13,3 |
To calculate the volume and quantity of 4-meter timber, you can use the following cheat sheet:
| Dimensions (mm) | Volume of 1 piece (m3) | Pieces per 1 m3 |
| 100x100x4000 | 0,04 | 25 |
| 100x150x4000 | 0,06 | 16,66 |
| 100x180x4000 | 0,072 | 13,88 |
| 100x200x4000 | 0,08 | 12,5 |
| 150x150x4000 | 0,09 | 11,11 |
| 150x180x4000 | 0,108 | 9,26 |
| 150x200x4000 | 0,12 | 8,33 |
| 180x180x4000 | 0,13 | 7,69 |
| 180x200x4000 | 0,144 | 6,94 |
| 200x200x4000 | 0,16 | 6,25 |
| 250x200x4000 | 0,2 | 5 |
As can be seen from the table, almost the entire range of beams here is fractional. Therefore, for an economical purchase, you should use our advice on paying the seller up to the whole amount of timber.
How to do this practically? Let's give an example. Let's say that we bought one cubic meter of 4-meter timber with a cross-section of 100x180 mm (according to the table, it turns out to be 13.88 pieces). The price of 1m3 is 6500 rubles. Up to 14 pieces of beams we need to pay an additional 14-13.88 = 0.12. The volume of this “piece” is (0.12 x 4 meters = 0.48 m) x 0.1 x 0.18 m = 0.00864 m3. We multiply it by the price of 1 m3 and get 0.00864 m3 x 6500 rubles. = 56.15 rub.
Remember that the purchased volume of bars must include a reserve (cutting losses during operation). Therefore, the result obtained in the process of theoretical calculation of the roof rafter system or other wooden structure, you need to multiply by a factor of 1.3. After this adjustment, you can begin settlements with the seller.
In addition to determining the volume and price of the purchased material, you need to know the weight of 1 m3 of timber in order to order transport of the appropriate carrying capacity.
The weight of a cubic meter of timber depends on the type of wood and its moisture content. Approximate weight 1 m3 of dry pine is 510 kg (wet - 890 kg).
The average weight of one cube of dry spruce bars is 450 kg (wet - 790 kg).
The weight of dried oak wood is in the range from 700 to 800 kg/m3, and wet (freshly cut) – from 980 to 1030 kg/m3.
Dry larch timber weighs 650 kg/m3. Freshly cut material of this type of wood weighs 840 kg/m3.
Repair and construction work often involves the use of lumber. But shops and timber trading centers often sell them not in pieces, but in cubes.
Everything is very simple and fast.
Method for calculating edged lumber
- a caliper, tape measure or folding m; if the length parameters of wood products are known, you can limit yourself to a regular ruler;
- calculator - suitable mobile phone, smartphone, if problems may arise with mental arithmetic;
- a piece of paper and a pencil - to record the results of calculations, how many boards are in a cube.
- Volume = Length × Height (product thickness) × Width.
To prevent confusion when converting cubic centimeters to cubic meters, it is more convenient to immediately record the measurement results in meters.
For example, 0.132 cu. m = 6 m × 0.022 m (2.2 cm) × 0.10 m (10 cm).
Now, to determine the number of planks in a cube, you need 1 cubic meter. m divided by 0.132. The result obtained (7, 5757) when purchasing timber must be rounded to 8 pieces.
This method of calculating cubic capacity is also suitable for timber. This way you can determine how many cubic meters of timber you need to purchase if you know the required number of products, or, conversely, determine required quantity cubes
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How to calculate the cube of an unedged board?
To determine the required volume of timber, the easiest way is to carry out calculations similar to the above method. Only the final result needs to be multiplied by 1.2 - a correction factor. From unedged boards you can get no more than 70-80% of edged ones.
The width and thickness of each product are measured taking into account its further processing. The technique will help determine the number of cubes wooden products, necessary for work, if the final result is planned for their further processing - pruning.
When purchasing, the widest and thinnest boards are measured to obtain an average width. If the width of the lumber at the butt is wider than at the top, the arithmetic mean of their dimensions is used without taking into account the bast layer or bark, rounded to 10 mm. In this case, fractions from 5 mm are rounded to the full 10 mm, and fractions up to 5 mm are not taken into account. The length and thickness of the lumber are measured in the usual way. The volume of timber is determined according to the usual scheme:
- the volume of one product is calculated;
- the total cubic capacity of purchased timber is determined; according to GOST, correction factors are used: 0.96 – for lumber from coniferous species, 0.95 – for lumber from hardwood wood
In addition to the piecemeal method for determining the volume of unedged lumber, the geometric method can be used.
Requirements for a package of unedged timber:
- lumber is laid tightly, without overlaps, in horizontal rows;
- on one side the ends of the boards are aligned;
- all sides of the package are strictly vertical: according to GOST, the offset individual products outward, inward should not exceed 0.10 m;
- The package of lumber must be the same width along its entire length.
Then the volume of the package is calculated, the resulting result is multiplied by the coefficient:
Starting construction or renovation wooden house, you have to purchase various boards, while the buyer knows the total length, but the seller sells lumber by volume. This article will help you correctly determine the number of any boards in one cubic meter, which will help you avoid purchasing too much lumber.
How to calculate the volume of edged boards
The volume of one board is determined in the same way that was used at school - by multiplying the length by the width and thickness. Or multiplying the width by the length and thickness. It doesn't matter in what order you multiply the board sizes, the result will always be the same. Eg, standard board“fifty” has the following dimensions:
- length 6 meters;
- width 20 centimeters;
- thickness 5 centimeters.
To facilitate multiplication, it is necessary to convert all dimensions to common units - meters or centimeters. It’s easier to carry out these calculations in meters, then you don’t have to divide the resulting number by a million to convert it to cubic meters.
- As a result of multiplication, we obtain the volume of one board 0.06 cubic meters.
- After this, divide the unit by 0.06 and get the number of boards in one cubic meter.
- We get the number 16.6666, which must be rounded to the nearest whole, that is, to 16, which will be the number of “fifty” boards in one cubic meter. It is always necessary to round down, because some of the boards may be slightly wider or thicker, they may not be laid tightly, or several boards from the package may be twisted. If all the boards turn out to be normal, then fractions can also be taken into account; this is especially true for thick timber.
Table of standard volume values
For your convenience, we have created a table with the most common sizes of boards and timber, as well as their quantity in one cubic meter
|
Size in millimeters |
Volume of one board cubic m. |
Number of boards in one cubic meter |
It would seem, why do you need to know how many boards there are in one cubic meter? After all, when large construction boards are sold in “m3” anyway and payment is made precisely for the volume, and if only a few pieces are needed, then the cost is determined by linear meters. Still, you should understand how such a calculation of material is made.
At proper organization At the first stage of work there is always such an item as planning. And not only the design and features of the future structure, but also material costs. Consequently, if, in accordance with the project, 40 boards are required, then, taking into account defects or inaccuracies, you will have to buy - with a reserve - 45 pieces. For this, you should calculate how many “cubes” you need to purchase and add a few more blanks to them.
Why?
Firstly, the number of boards in 1 m3 depends on their parameters (thickness, length, width). Naturally, for each size their number in the “cube” will be different.
Secondly, When carrying out any work, be it a new building or a renovation, different boards are always used. For the rafter system - one, for the floors - another.
Third, buying extra material is a waste of money. Of course, the boards will come in handy later, but they need to be stored somewhere. And not just abandon it on the site, and then get “rotten”, but provide proper conditions. And given that we have never had a shortage of wood, is it worth purchasing significantly more than we need?
Fourthly, time factor. What if there are not enough boards when purchasing in cubic meters? What, stop work, look for freight transport, waste time going to places of sale?
And fifthly, You should not hope that the Seller will answer such a question. IN best case scenario– will offer to count the boards in the stacks yourself, if interested. At worst - on purpose or out of ignorance - he will deceive.
We offer you a table with ready-made data:
It only has 3 columns. The first indicates the dimensions of the workpieces (in “mm”), the second – their quantity per 1 m3, and the third – the volume of 1 board (also in “m3”). There is nothing complicated. You just need to find the corresponding line, and the answer to your question is received.
By the way, it's very convenient. If you multiply the entire required number of boards by the volume of one, it will become clear how many “cubes” you will have to purchase, which means how much money you will have to spend. This is exactly what a prudent owner should do. And you don’t need tables, just use a calculator.
This table provides data for both edged and unedged boards. In addition, there are calculations for, which is also often used in construction or repair.
In principle, this is quite enough.
Note
All of the above is true if you purchase edged boards. But it also costs more. It is more economically profitable to take unprocessed material if you have the opportunity to trim it yourself. But in this case it is necessary to apply a coefficient when calculating. Experts believe that 20–30 percent of unedged lumber will go to waste. Therefore, from 1 “cube” ready-made boards it will be less.
Construction work requires solving many different issues, among which the most important task is the selection and purchase of lumber. It is not difficult to calculate how many linear meters of boards and timber will be needed during the construction process. But the price of industrial wood is indicated per 1 cubic meter, and this often causes difficulties for novice home craftsmen. The ability to correctly select and calculate the amount of edged or unedged lumber in a cube will allow you to save money and avoid a situation where, after completion construction work There is a pile of unused boards left on the site.
Classification and characteristics of lumber
The very name “lumber” suggests that this type of construction raw material is obtained by longitudinal sawing of tree trunks on circular or band saws. Several cutting methods are used to produce boards and timber:
- tangential (in a circle),
- radial.
Tangential cutting involves moving the saw tangentially to the annual rings of the tree, which reduces the amount of waste and, therefore, reduces the cost of building materials. The boards obtained in this way have a beautiful, pronounced pattern, therefore they are often used for finishing purposes. Disadvantages of circular sawing include the tendency of the wood to shrink and swell, as well as a significant difference in texture as it approaches cutting tool to the center of the log.
In the sawmill industry, several methods are used for sawing a trunk.
At radial sawing the cutting line passes through the core of the tree, so the yield of boards will be smaller, and their price will be higher. However, if necessary, obtain wood High Quality use exactly this method. This is due to the fact that, compared to the tangential method, radial sawing boards have halved swelling and shrinkage rates. In addition to the cutting methods discussed above, they also use mixed method, which combines the advantages of the first two.
The concept of lumber actually includes not only traditional timber, which is most often seen in construction markets. The full list of products obtained from sawing logs includes:
- board;
- beam;
- bar;
- lagging;
- croaker
The last two types of lumber are classified as waste, which absolutely does not prevent them from being used for certain types of construction work, as well as for finishing purposes.
Boards
Boards include lumber rectangular section with a thickness of no more than 100 mm and a width to thickness ratio of no less than 2:1. Depending on the degree of processing, the board can be edged or unedged. The first is ready product without bark and with smoothly sawn edges, while the second is a “semi-finished product”, removed directly from the saw frame.
Edged board has smooth edges and a constant width along the entire length of the lumber
The most commonly used boards in construction are the following standard sizes:
- thickness - 25 mm, 40 mm, 50 mm, 60 mm;
- width - from 75 to 275 mm with gradation every 25 mm;
- length - from 1 m to 6.5 mm in increments of 250 mm.
Boards of other sizes can be obtained by trimming or planing standard lumber, or by making individual order for sawing round timber.
Unedged boards have a lower cost, but without finishing its scope of application is limited
The parameters of lumber used in construction are standardized and determined according to the current GOST 8486–86 for coniferous wood and GOST 2695–83 for hardwood.
timber
Timber is lumber whose cross-section is a square with sides of at least 100 mm. The diameter of the timber is unified and can vary from 100 to 250 mm in increments of 25 mm. The standard defines the length of products of this type from 2 to 9 m, but most often square lumber with a length of no more than 6 m is used. In some cases, products with a section of 150x100 mm, 200x100 mm or 200x150 mm, which existing classification are much closer to the sleepers.
The timber is ideal material for the construction of frames and other wooden structures
The bar differs from the beam discussed above only in that its cross-section does not exceed 100x100 mm. The typical length of the bar is also 6 m, and the diameter ranges from 40 mm to 90 mm in increments of 10 mm. To simplify the classification, bars are often classified as slats whose cross-section has rectangular shape, and the ratio of thickness to width is at least 1:2. The standard range of edges for softwood slats looks like this: 16, 19, 22, 25, 32, 40, 44, 50, 60, 75 mm. For hardwood lumber, products of increased width are additionally provided, and the product line itself looks like this: 19, 22, 25, 32, 40, 45, 50, 60, 70, 80, 90, 100 mm.
A variety of bars and slats allow you to strengthen and make any wooden structure as stable as possible.
Obapole and croaker
Obapol is the very first cut of a round timber, the outer surface of which remains untreated. Unlike obapol, croaker can have a cut on half of the second side or alternating treated and untreated areas on the bark side. The importance of obapole and slab in construction is secondary, since it is unaesthetic appearance and reduced performance characteristics make it possible to use lumber of this type only for auxiliary purposes. Most often, slab and obapol are used as fastening materials, as well as for the manufacture of formwork, sheathing or flooring. scaffolding. This material is also interesting in quality decorative material for decorating walls, fences and other vertical structures.
Despite their external ugliness, croaker and obapole are widely used for minor construction tasks
Technology for calculating the number of boards in a cube
The wood market offers both edged lumber and unedged boards, with wane remaining on the edges. Depending on the type of wood products, several methods are used to determine cubic capacity.
How to find out the number of edged lumber in a cube
The algorithm for determining the cubic capacity of lumber is based on the formula for finding volume known to every schoolchild rectangular parallelepiped. In order to find out the cubic capacity of one board (V) per cubic meter. m, you need to find the product of its length (a) by its width (b) and thickness (h) in meters V=a×b×h.
The desired figure will make it easy to calculate how many boards of this type will fit in one cubic meter lumber. For this, 1 cu. m of lumber is divided by the volume of one product. For example, if you need to find out the cubic capacity of one board with parameters 6000x200x25 mm, then by substituting these numbers into the formula, we get V = 6x0.2x0.025 = 0.03 cubic meters. m. Consequently, in one cubic meter there will be 1/0.03 = 33.3 such products.
A tongue and groove board has a groove on one side and a tongue on the other. Since both of these elements are approximately equal to each other, their parameters can be neglected. That is why the cross-sectional size of tongue-and-groove lumber is measured without taking into account the locking part.
In the case of boards that have same sizes, the calculation can be simplified by substituting the dimensions of the lumber stack into the formula. Of course, its installation should be as tight as possible, otherwise the gaps between separate elements will affect the accuracy of the calculations. Considering that the cost of individual types of wood reaches tens of thousands of rubles, such an error can cost a pretty penny.
To simplify calculations, you can use special tables that allow you to quickly determine the cubic capacity or the amount of wood in 1 cubic meter. m of lumber.
Table: number of edged boards in 1 cubic meter. m of standard length lumber
| Board size, mm | Number of boards 6 m long in 1 cubic. m | Volume of one board, cubic meters. m |
| 25x100 | 66,6 | 0.015 |
| 25x150 | 44,4 | 0.022 |
| 25x200 | 33,3 | 0.03 |
| 40x100 | 62,5 | 0.024 |
| 40x150 | 41,6 | 0.036 |
| 40x200 | 31,2 | 0.048 |
| 50x100 | 33,3 | 0.03 |
| 50x150 | 22,2 | 0.045 |
| 50x200 | 16,6 | 0.06 |
| 50x250 | 13,3 | 0.075 |
The cubic capacity of timber of standard sizes can also be determined using the table below.
Table: amount of timber in 1 cubic meter. m of lumber
| Beam size, mm | Number of products 6 m long in 1 cubic. m | Volume of 1 beam, cubic. m |
| 100x100 | 16.6 | 0.06 |
| 100x150 | 11.1 | 0.09 |
| 100x200 | 8.3 | 0.12 |
| 150x150 | 7.4 | 0.135 |
| 150x200 | 5.5 | 0.18 |
| 150x300 | 3.7 | 0.27 |
| 200x200 | 4.1 | 0.24 |
Very often it is necessary to determine the surface area (floor or wall) that can be covered with a board of one thickness or another with a volume of 1 cubic meter. m. To do this, you can use the formula S = 1/h, where h is the thickness of the lumber. So, one cubic meter of 40 mm board will be enough to arrange S = 1/0.04 = 25 square meters. m of floor. To facilitate the process of calculating the area, a table called a cubeturner allows you to simplify the process of calculating the area. It contains data on the cross-section of the boards, their number in 1 cubic meter. m and the required area that they can cover.
Method for calculating the cubic capacity of an unedged board
Unedged lumber is not trimmed at the edges, so not only the cross-sectional size of individual products varies, but also the width different parts one board. In this regard, it is possible to calculate the volume of a stack of unprocessed lumber only approximately. The same applies to calculating the cubic capacity of individual unedged lumber, although the error in this case will be much smaller.
So, to calculate the cubic capacity unedged boards There are two constant quantities - thickness and length, and one variable - width. To avoid complex calculations using differential algebra methods, the last parameter is simply averaged. To do this, the board is measured in several places and the arithmetic average is found. For example, for a board with a diameter of 400 mm at the base, 350 mm in the middle and 280 in the top, the calculated value will be (430+340+260)/3=343 mm. Further calculations are carried out in exactly the same way as for edged lumber.
Most often, the width of an unedged board is determined only on the basis of measurements along the edges of the lumber. It should be noted that the accuracy of calculations directly depends on the number of measurements, so in critical cases their number is increased.
If you need to find out the cubic capacity of the package unedged wood, then the products are stacked on top of each other in such a way that the following conditions are met:
- the stacks must be aligned along the front end;
- boards in a stack should not be stacked overlapping;
- It is not allowed to change the width of the package along the entire length of the lumber;
- the protrusion of the outermost products beyond the stack should not exceed 100 mm.
By measuring the height, length and width of a package of unedged wood with a tape measure, the approximate cubic capacity is determined using the formula V=a×b×h. To find out more exact value, the resulting result is multiplied by the stacking coefficient, which can be found in special tables.