All about the size of edged boards

Edged board is the most popular lumber. It is used both for the creation of load-bearing structures (beams, supports, foundations, roofs), and for finishing, decorative work, the manufacture of furniture, packaging and many other domestic and industrial tasks.

Consider in the article what the dimensions of the edged board are, what they depend on, how to make sure that the material meets the declared parameters and standard.

A typical edged board is a rectangular piece of wood that has been sawn from all sides. It is made by radial or tangential cutting of a log. The most common option is a part with perpendicular edges. Although there are also single-sided and double-sided edging materials, workpieces with non-parallel edges. Wane (the remainder of the bark) is acceptable, but not more standard.

The most important characteristic of the board is its dimensions.... It depends on them what kind of load it is designed for.

In terms of dimensions, the edged board has 3 characteristics:

• thickness - the distance between two large longitudinal surfaces (layers), for a board, this parameter cannot exceed 100 mm (everything that is larger is already a bar);
• width - the size between the sides (edges), according to GOST, the width of the board should be twice the thickness;
• length - the minimum distance between the ends.

Dimensions depend on several factors. Let's consider them in more detail.

The main factor that determines the size is humidity. A wooden product with different humidity can have different parameters. At room temperature, in a dry, warm room, the dimensions will be smaller, and outdoors, in humid air, a little more. That is, the board "breathes", it does not have a strictly fixed size under any conditions. This must be borne in mind when selecting material, distinguishing between nominal and actual sizes:

• nominal - reference dimensions, which are indicated in the marking at a standard humidity level (according to GOST - for a humidity of 20%);
• actual dimensions - the dimensions of the material when it is measured at a given time and at a given humidity.

That is, if, when measuring, the dimensions differ from those indicated in the marking in accordance with GOST, this does not mean that the material is of poor quality. But it is important - it must differ from the standard size strictly by the value of the shrinkage coefficient. This coefficient is different for each breed. For conifers, the values ​​are given in GOST 6782.1, for deciduous ones - in GOST 6782.2-75.

Also, these coefficients must be taken into account in the manufacture of lumber. If a log is sawn that differs in moisture from 20%, then the workpieces are made larger in size by the required factor, so that after drying they acquire the parameters corresponding to the standard.

After shrinkage, the boards in the batch may differ slightly in size. Therefore, the standard for edged materials has established permissible deviations:

• width - 2 mm;
• thickness - 1 mm for thin boards (up to 32 mm), 2 mm - for thick boards (over 32 mm);
• length - up to 50 mm upward, up to 25 - downward.

If it is necessary that the boards in the batch were selected of the same size with even higher accuracy, they can be specially sorted (manually or with the help of special equipment), and also subjected to calibration - that is, processing (trimming, trimming) to give the specified parameters.

In accordance with GOST, boards of no more than 22% moisture are used for any work. Lumber with a higher moisture content is considered damp (natural moisture), it differs from dry, is prone to deformation and decay, therefore, requires drying and processing.

Different breeds have their own characteristics due to their structure - they dry in different ways, are cut, processed, impregnated with protective compounds, have different densities, therefore they are used for different types of work (for example, boards made of soft hardwood are not suitable for creating load-bearing structures). Based on this, there are size standards for different categories of species - coniferous, soft and hard deciduous.

Boards of different types, according to the purpose and degree of processing, can have different sizes.

• Regular (untreated) edged board is made of standard dimensions, in accordance with GOST.
• After additional processing of a regular board (for example, peeling, trimming), its dimensions may change. Therefore, there are options for planed and sanded boards that differ in size from standard edged sawn timber.
• In addition to typical edged boards, materials are produced that are adapted to specific tasks - for example, to create bridge supports. Based on the specifics, they have their own standard sizes that differ from those that exist for ordinary boards.
• Profiled, finishing, grooved boards are presented in a variety of options (floor, front board, decking, block house, lining, planken and others). These are boards that have a special, complex section geometry that differs from a rectangle. They can be supplied with grooves, protrusions, a lock for better fastening to each other. Depending on the specifics, they also have their own standard sizes that differ from standard edged boards. Moreover, for a number of varieties (for example, for a facade board) there are no GOSTs, they are produced according to the manufacturer's standards. Therefore, you can, for example, find finishing and facade materials with a thickness of 8, 10, 14 mm, while for a standard edged board in accordance with GOST, the minimum thickness is 16 mm.
• Boards produced for export may have special cross-sections (for example, 63x160, 50x300, 60x300, 75x300, 100x300 mm).

Consider the sizes of standard edged boards.

Standard sizes of materials for conifers are determined by GOST 24454-80. They are as follows:

• in thickness 10 gradations from 16 to 100 mm - 16, 19, 22, 25, 32, 40, 44, 50, 60, 75 mm;
• 9 gradations in width with a step of 25 mm - 75, 100, 125, 150, 175, 200, 255, 250, 275 mm;
• in length - from 1 to 6.5 m with a step of 250 mm.

Cross-sectional options (combination of thickness and width) are presented in GOST 24454-80 in the form of a table. In the left column, the standard sizes are given by thickness, in the columns on the right it is indicated which of the 9 gradations of width are used in combination with this thickness.

For example, with a minimum thickness of 16 mm, only 4 options are used - 75, 100, 125 and 150 mm... In other words, such a board has only 4 possible section options - 16x75, 16x100, 16x125, 16x150 mm. And, for example, for a board with a thickness of 25 mm, all 9 variants of the size of the face are allowed. Accordingly, its sections can be as follows - 25x75, 25x100, 25x125, 25x150, 25x175, 25x200, 25x255, 25x250, 25x275 mm.

As follows from the table, the minimum section of the edged board in accordance with GOST is 16x75 mm, the maximum - 100x250 mm.

The dimensions of hardwood materials are regulated by GOST 2695-83:

• in thickness 12 gradations from 19 to 100 mm - 19, 22, 25, 32, 40, 45, 50, 60, 70, 80, 90, 100 mm;
• 10 options in width from 60 to 200 mm - 60, 70, 80, 90, 100, 110, 130, 150, 180, 200 mm.

The length depends on the breed:

• for hardwoods - from 0.5 to 6.5 m with a step of 100 mm;
• for soft hardwoods and birch - from 0.5 to 2 m in increments of 100 mm, from 2 to 6.5 m in increments of 250 mm.

Materials from soft deciduous species can also be produced according to the dimensions of conifers (according to GOST 24454-80).

Russian companies have developed the following line of running standard sizes:

• thickness - 20, 25, 30, 32, 40, 50 mm;
• width - 100, 120, 150, 180, 200, 250 mm;
• length - 6, 3, 4 m.

The section can be any combination of the given thicknesses and widths.That is, with a thickness of 20 mm, the width can be 100, 120, 150, 180, 200 or 250 mm. The same applies to other thicknesses.

The most optimal length is considered to be 6 m. Among such boards, the most popular options are 20x150x6000, 30x150x6000, 45x150x6000. Boards of 3 and 4 meters are considered, according to the unspoken standard of manufacturers, to be shortened. They are also in great demand among consumers. For example, boards 30x150x3000, 50 x 150 x 3000 mm are in great demand in private construction.

Wide boards of 300 and 350 mm are in great demand, and although they are not considered standard, many manufacturers include them in their lines.

A planed board in accordance with GOST must have the same dimensions as a regular edged board. Appropriate machining allowances are set by the manufacturer at the stage of log sawing. But sometimes a planed board is obtained from a standard size edged board. It is planed on a special machine and polished, and before that, it is often dried in a thermal chamber.

This option is often more profitable for the buyer. But it should be borne in mind that after all the manipulations, the section of the board will decrease by 5-10 mm, compared to the typical size according to GOST. For example, an ordinary board 25x150 after processing will acquire dimensions of 20x145 or 20x140 mm. And you need to calculate the amount of material based on this final size, and not from the standard one.

Product information is contained in the label. According to GOST, the size must be indicated there. Moreover, it is permissible to indicate only the cross section - for example, 20x150, 45x180. Responsible manufacturers usually indicate all 3 dimensions, including length. That is, the designation is done in the format 20x150x6000, 20x150x3000, 50x250x4000. Dimensions are in millimeters.

In addition to dimensions, the marking also indicates:

• product type (board);
• grade;
• tree species;
• GOST number.

We emphasize again: the marking indicates the nominal dimensions at a humidity of 20%.

Therefore, in order to know the actual dimensions of the board and to make sure that its parameters meet the standard, it is recommended to carry out a control measurement when purchasing the material and before shipment. It is also necessary to know the real dimensions in order to correctly determine the volume (cubic capacity), and, accordingly, correctly calculate the cost (the price of lumber is usually indicated per cubic meter).

For edged boards, you can measure the dimensions of one piece in a batch. However, it is better to try on several, ideally all boards, if the party is small. The length and width of the lumber are determined using a tape measure, the thickness using a tape measure or caliper.

Measurements are made as follows:

• length is defined as the distance in a straight line between the ends;
• width and thickness are measured anywhere, but closer than 150 mm from the edge, while measurements are taken between two edges in a direction perpendicular to the longitudinal axis;
• thickness - also measured anywhere with an indent of 150 mm from the edge, in a direction perpendicular to the faces.

All measurements are taken without taking into account the bark, if any.