Since the appearance of GOST standards regulating the classification of all lumber into different types of grades, manufacturers have been trying to subdivide imitation timber. But the specifics of the manufacturing technology of this material are very subtle and the standards applied several decades ago are no longer relevant. This is what forces the manufacturer to develop their own schemes and characteristics that divide the imitation timber by grade. This article is about the varieties of imitation timber, the subtleties of division and their quality characteristics.

The division into grades of imitation timber is directly related to its appearance. There are smooth panels that look illusionary like artificial material, and there are knotty panels with flaws. The latter lose their aesthetic appearance and belong to a lower grade. Buyers prefer to choose the “golden mean”. But do not think that the lowest grade is not suitable for finishing. Since even small errors in the manufacture of panels classify it as a lower type. Imitation timber practically does not lose its mechanical properties. Of all the criteria for dividing imitation timber, two can be distinguished:

1. The number of flaws and defects in the finished product.
2. Mechanical damage during the manufacture of imitation timber.

Varietal division of imitation timber

A total of 5 varieties of imitation timber can be distinguished:

1. "Extra"
2. Mixed type (AB, BC).

It is important to understand:

1. Imitation timber of any type is produced using one technological process.
2. One batch of wood is used for production.
3. Drying takes place in one drying chamber at one temperature.
4. During production, all varieties undergo the same processing on the same machines.

All panels are sorted already at the packaging stage. For these reasons, you should not neglect the lower grade. Each variety has its own deviation standards, from which a deviation above the permissible standard already classifies the panel into a lower category. Sorting norms can be presented in table form:

It is worth talking about each type separately and in more detail.

Types of imitation timber and their characteristics

When dividing classes of imitation timber, do not forget about the value of the wood from which the panels are made. For example, pine has large knots, reaching the size of half a panel, and a dark, rich color. And the linden knots are small and infrequent, their color is light and even. This means that imitation timber from class B linden will look no worse than class A pine.

Class A and Extra

These are the highest grades of imitation timber. Many manufacturers even combine them into a single line. The boards are even, smooth, and have minimal knots (1-3). Mechanical damage is not allowed completely. The geometric shape is perfectly flat. The price for these varieties is the highest. But it is worth noting that the real Extra variety is not produced in Russia. Typically, manufacturers sell grade A under the guise of Extra.

Class AB

This type of imitation timber differs from A and Extra only in the presence of resin pockets. Their size does not exceed 3 mm. May have 1-2 knots per meter of product. The color of the knots will depend on the type of wood, but they are always alive and not rotten.

Class B

The geometric shape of this type of imitation timber may be disrupted, but not significantly. The surface may have abrasions and gaps during sanding. The number of knots exceeds 3 and they are on the front side. Mechanical damage is allowed, but minor. There are more than 2 resinous pockets. There may be small chips and cracks up to 0.5 mm deep.

Class C

This is the lowest grade material. With knots and mechanical damage. There may be fallen knots and unevenness in the tenon and groove. Cracks with a depth of more than 0.5 mm are allowed. Tar pockets and even chips. But these panels are the cheapest, and with good installation and proper processing, their appearance will be no worse than that of V.

Aircraft class

This mixed grade of imitation timber allows for the presence of fallen knots and mechanical damage. But they are not significant, which does not give the right to classify it as class C, but there is no way to talk about B either.

Each of the listed classes of imitation timber from pine, cedar, spruce, birch, linden, etc., has its own quality characteristics. They can be seen in the table:

*- Not allowed

In addition, there are a number of characteristics that may not be present in all types of imitation timber:

• Rotten fallen knots forming through holes on the panels;
• Resin pockets greater than 8 mm in size and more than 4 mm deep;
• Wane in any place where it will be visible after installation;
• Mechanical damage on the front side;
• Humidity of panels is more than 13%;
• The fringe is visible after finishing.

Price for different types of imitation timber

The price is directly related to the types of panels. Of course, the type of wood, the time of year, and even the additional costs of the manufacturer play an important role. But we will take as an example panels made of the same type of wood (pine). This will make it clear what the price difference is between different varieties.

For exterior decoration of a house, imitation timber of grade B or AC is usually used. But if it is important for you that the cladding is the best, and the price is not scary, then of course you can use grades A and Extra. But let’s say right away that grades AB and B of imitation timber will look no worse after finishing and painting.

Currently, lumber manufacturers offer two types of boards: edged and unedged. We use both types of boards in the production of wooden containers; the range can be found in the catalogue.

The edged board has a regular rectangular shape and is a single piece of wood, even along the edges and cleared of bark. The level of bark removal and the degree of processing are determined by the required grade of edged boards. Such a board can be used in production without additional processing.

An unedged board is made by sawing an untreated log in such a way that the board is smooth on both sides, and rounded untreated areas covered with bark remain on the sides. This type is 2-3 times cheaper than edged and is used mainly for the manufacture of wooden boxes whose appearance is less important.

Types of boards

The main criteria for dividing into grades are moisture, deformation during drying, clear dimensions, the presence of knots and other irregularities. There are 5 grades in total, ranging from selected “Lux class” boards to “E” class wood scraps.

0th grade They are mainly used in shipbuilding and automotive production. Grade 0 boards are used to make the “sides” of trucks, interior elements of car interiors and cabins, deck boards, and masts for yachts. The main requirements are that large knots are visible, no more than 2 meters at a distance from each other. Rotten knots and parts of wood are not allowed. The presence of cracks should not exceed 10%, mainly formed as a result of shrinkage. The wood must not contain parts of the root system, the lumber must be clean.

1st grade used in furniture production, industry. Rotten and falling out knots more than 10 mm, through cracks with a depth of more than 1 mm and a length of ¼ of the length of the board are not acceptable. There should be no elements of rotten wood, as well as elements of “dead” bark or an overgrown wound. Rottenness, elements that are gray in color, mold or inclusions of foreign parts are not acceptable. This type of board is used in production.

3rd grade wood is considered to be of low level, but also with a very low price. It is mainly used in the packaging industry, usually for disposable boxes, transport packaging and other wooden packaging where appearance is not so important, but large intergrown knots and end cracks to the full depth are not allowed. Almost all other defects are acceptable, even rotting and damage to the wood layer and sharp bends of the fibers. As a rule, boards of the 3rd grade are scraps from the first and second grades of lumber.

Common people are often confused about the concepts - what is lining grade A, AB, C? Practice shows that domestic consumers are now quite demanding on the quality of linings. For this reason, the good old DIN 68 126 (and even more so GOST 8242-88) in fact turn out to be too soft. Because of this, we and our manufacturers have to work according to our own technical conditions - more stringent than all existing regulatory documents, where holes from fallen knots or blue spots on the front surface can be considered the norm.

In total, on average, it is customary to distinguish 4 types of planed products. They can be called differently. In most cases, manufacturing companies offer one category with the highest standards - Extra, Premium, Ultra, Selected... And they also sell eurolining of another 2-3 quality levels: I; II; III – grades, or categories are designated by letters: A; IN; WITH.

In addition to the main varieties, classes and categories, you can often find intermediate options, for example, BC or AB. Let's take, for example, a lining of category AB, which in terms of quality represents a batch of products in which, along with parts of a higher grade A, there is also a certain amount of products of grade B. Why does the manufacturer do this - you ask? It's very simple.

The intermediate class AB is not intended to deceive the client. When fraudsters seek illegal profit, they simply sell low-quality products under the guise of high-quality ones, for the same money, to the point that they can mix in category A everything that is available, including products of the 3rd grade or even complete rejection .

A normal manufacturer is tasked with making the most of sawn raw materials. The fact is that a tree is a living and unique organism, what is the structure of the trunk - it is not clear before sawing how the cut board will behave during the drying and planing process.

Moreover, the longer the log is sawn, the greater the likelihood that some kind of defect will get into the finished product. This is especially true for knots, which are parts of branches, and the higher up the trunk, the more branches there are. That is why the yield of linings longer than 4 meters that fall under the criteria of selected or first grade is very small. This is not to mention the first-class 6-meter lining, of which, out of 20-25 pieces, only 1-2 pieces can be selected from one loose trunk. This is why long-length lining of pure category A is so expensive.

That is, the AB grade, with fairly acceptable quality, allows the consumer to save more than 20 percent of money, having received quite decent material upon purchase, which, if used correctly, can solve very serious problems.

Grade A lining

Grade B lining

Clapboard grade C

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Wood grades according to DIN 68126

Wood grades according to DIN 68126 are classified as Extra, A, B, C. There is a method of sorting into narrower subgroups, for example grades with A1, A2, A3, A4 (A1 has 1 knot per 1 meter, A4, respectively, 4 knots per 1 linear meter ). And there is a second way - simplification, i.e. there is a grade AB, a grade BC. This method is used when marking long-length lumber; the most popular example is block house and imitation timber, which are manufactured in a length of 6 meters. This is done in order not to reduce the grade of the entire board due to the presence of a section of reduced grade on it.

The procedure for assigning wood grades according to DIN 68126 to grades A, B, C

1. In the total volume of shipped products, the presence of up to 5% of material of a lower or higher grade is allowed, i.e. Every 20th board can be of a different type.
2. The grade of wood is determined on the least quality one-meter section on the front side of the lumber.
3. The size of the knots is determined between the tangents to the contour of the knot parallel to the longitudinal axis of the lumber.
4. The size of stitched and oblong knots is taken equal to half the size determined according to the rules of clause 3
5. In sawn timber longer than 3 m, one knot of a lower grade is allowed.
6. The number of knots in beams is not standardized.

Download Grades according to DIN 68126 in PDF format

Photo of wood defects

Domestic standards for determining wood grades

| Wood types: GOST | Selected board | Board 1 grade | Board 2nd grade | Board grade 3 | Board grade 4 |

Printable version of the page

The article Wood grades according to DIN 68126 was modified: April 19th, 2018 by LesKhimProm LLC

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Types of wood

Requirements for product grades for the Elite, Prima, A, B, C assortment

Larch lumber grade EXTRA

Not allowed: knots, cracks, core. Also, the presence of resin pockets, rot, and insect damage is not allowed. There may be a tolerance for length +\- 50mm, width +\-1mm, thickness +\-0.5mm.

Larch lumber grade PRIMA

Allowed: 1-2 knots, up to 5 mm in size per product, one resin pocket per product. Not allowed: cracks, core, rot, insect damage. There may be a tolerance for length +\- 50mm, width +\-1mm, thickness +\-0.mmm

Click on the picture to enlarge

Larch lumber grade A, B Allowed: - healthy, firmly fused knots up to 3 cm, without restrictions; - small black 5 mm - 4 pcs., per product; - knots with a black edge up to 10 mm - 3 pcs., per product ;- firmly fused healthy knots on one side up to half - 2 pcs. per 1 m of length; - thin cracks up to 3 cm, not through, located near the ends of the product. - separate resin pockets with a surface of up to 2.5 square meters. see One resin pocket per product. - resin lesion, if this does not impair the appearance of the product. One per product. Not allowed: - rot, traces of wood damage by insects.

There may be a tolerance for length +\- 50mm, width +\-1mm, thickness +\-0.mmm

Click on the picture to enlarge

Products made from larch of any type have precise geometry. We invite you to visit our warehouse and make your choice at the address: Avtovskaya St., 31.

All of the above requirements for product quality apply to the front side of the product.

Explanation of terms

KnotsA knot is the base of a branch enclosed in the wood of the trunk.

CracksTearing of wood along the grain

CoreThe central part of the trunk, consisting of loose tissue of brown or lighter color than the surrounding wood.

Roll, cross-layer Deviation of wood fibers from the longitudinal axis of the assortment

Resin pockets Resin pockets are the cavities between the annual layers filled with resin.

Sprouting Overgrown bark in the trunk or dead wood as a result of external damage.

RotDestruction of wood by various fungi

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What types of eurolining needles are there: sizes and varieties

Why does wooden eurolining occupy a leading position in modern markets for finishing materials? There are no special secrets here, and the answer has been obvious for thousands of years. Wood is a natural building material that has excellent qualities. It retains heat, is pleasant to contact, and with special treatment can withstand high levels of humidity. Wood is a frost-resistant material, even despite its ability to change density with temperature changes.

Choosing euro-lining pine needles

Eurolining

Eurolining is a wood material that has retained all the properties of a natural element. The big advantage is the unique locking system, which allows you to conveniently and quickly lay the lining, without the use of additional adhesive materials. Eurolining can be made from almost any type of wood. The most popular are pine needles and larch. Needles have a wide price range, including ordinary pine and expensive cedar.

But we'll look at the most popular material. Moreover, simple euro-lining pine needles are used to organize baths, saunas, gazebos, balconies, etc. At the same time, lining is not always finished in a wooden house.

Species

And let's start, perhaps, with the types of eurolining, or rather, classes. The material is specially divided into them to make it easier to determine the scope and price range for the lining. Let's look at each one separately.

Extra

This is the highest grade or class of lining. The main distinguishing features of such a tree will be its exceptional appearance. Such lining should not have the slightest defect. It is made from the most durable parts of tree trunks. The structure of the wood must be uniform, without small cracks, depressions, knots, etc. Moreover, this applies to the entire length of the product. Naturally, the cost of such lining will differ significantly from lower classes. It is often used for interior decoration of rooms, decoration in wooden houses, relaxation rooms in bathhouses, etc. As for special qualities, such as resistance to moisture and temperature changes, with special treatment, needles may well meet all the requirements when organizing a sauna or bathhouse.

Grade A

This is a material that is manufactured according to GOST and must meet a number of requirements. Firstly, eurolining made from class A needles should not have through cracks. Secondly, the grinding of the material must be perfect. Thirdly, the smallest cracks up to 5 mm are allowed, but no more than 2 for the entire product. Fourthly, it is possible to have one knot over a length of 1.5 m, but its length should not exceed 3 mm.

Grade B

This is a medium-cost class, which is often used for interior decoration. The main characteristics, naturally, depend on the natural material, however, GOST establishes certain qualities that should not be violated for this class. Eurolining grade B implies the presence of whole knots, as well as small short cracks and slight roughness.

There is also grade AB, that is, the lining includes acceptable defects in grades A and B. It costs even less than B. It is often used for finishing secondary rooms: corridors, balconies, etc.

Grade C

This is the lowest grade in existence. Its characteristic feature, in addition to its low cost, is the presence of larger defects than in previous classes. It allows the presence of wood stains and wood heterogeneity. Class C lining may have falling knots, some mechanical damage, and blue discoloration. However, it is important that mechanical damage can occur on top and should not affect the overall quality of the finish. Usually this material is taken for finishing for painting. Then there is no particular difference in strength with higher grades.

In any case, the needles must be processed, since without this the wood will not have any protective properties. It is also important to pay attention to the further use of the material. There are special primers, varnishes and paints for pine needles that protect it from environmental influences.

Dimensions

The dimensions of euro-lining made from pine needles can also be of several sizes:

• length - 1.5; 2; 2.1; 2.7; 3 meters;
• thickness - 12.5 mm;
• width - 45; 96; 120 mm.

For eurolining made from needles (spruce, pine), wood is used that is harvested directly at the site of timber extraction. Large production enterprises are located in the north-west of Russia, in the Karelian and Arkhangelsk regions.

You can buy eurolining either using online services or in some large construction stores.

Let's sum it up

It only remains to add that for most types of finishing, pine needles are an ideal option also due to the light color of the wood. And the special aroma that hovers in the air of a room decorated with this material forces an increasing number of people to use just such a lining. A pleasant atmosphere at home is guaranteed.

Wood grades according to DIN 68126 classified as Extra, A, B, C. There is a method of sorting into narrower subgroups, for example, varieties with A1, A2, A3, A4 (A1 has 1 knot per 1 meter, A4, respectively, 4 knots per 1 linear meter). And there is a second way - simplification, i.e. there is a grade AB, a grade BC. This method is used when marking long-length lumber; the most popular example is block house and imitation timber, which are manufactured in a length of 6 meters. This is done in order not to reduce the grade of the entire board due to the presence of a section of reduced grade on it.

The procedure for assigning wood grades according to DIN 68126 to grades A, B, C

1. In the total volume of shipped products, the presence of up to 5% of material of a lower or higher grade is allowed, i.e. Every 20th board can be of a different type.
2. The grade of wood is determined on the least quality one-meter section on the front side of the lumber.
3. The size of the knots is determined between the tangents to the contour of the knot parallel to the longitudinal axis of the lumber.
4. The size of stitched and oblong knots is taken equal to half the size determined according to the rules of clause 3
5. In sawn timber longer than 3 m, one knot of a lower grade is allowed.
6. The number of knots in beams is not standardized.

Photo of wood defects

Wood grade - general information, classification and regulatory requirements for lumber

In 99.9% of cases, if it is necessary to construct a wooden building, lumber is purchased in ready-made form. When choosing, it is simply vital to understand the intricacies of dividing wood into grades. This will not only help you choose the best option for each case, but in some situations it will also help you save money, for example, some sellers use double designations like AB wood grade, although this is a purely psychological technique to justify an inflated price.

General information about lumber

The term “lumber” covers a whole range of different products, from slabs to beams, which can easily be used as load-bearing structural elements. Before you begin to closely study the grade of wood, it would be a good idea to understand the classification of lumber (see also the article “Do-it-yourself wooden gazebo: main points”).

Classification can be performed according to a number of criteria.

For example, by assortment you can distinguish:

• croakers;
• beams and beams;-
• both sexes;
• sleepers;
• boards of various thicknesses - these lumber are especially popular; almost no DIY construction project can do without them.

The list of types of lumber is quite large

If we take the processing method as a basis, then we can distinguish the following types of lumber:

• edged and non-faceted. In the first case, cutting to length occurs, in the second - not;
• with different processing methods. Calibrated lumber is lumber not only dried to a given moisture content, but also processed taking into account the required dimensions, planed - at least 2 edges or 1 plane must be processed by planing, lumber can also be produced edged, single-edged and unedged;
• Based on strength, a separate class of structural lumber is distinguished. Hardwoods are used for production.

Pay attention! Only hardwoods such as oak, larch, etc. are used as structural lumber.

Limit on number of defects

Regulatory Requirements

In relation to lumber, the requirements are quite stringent, and they relate not only to size, but also to the level of humidity, number and types of defects. GOST for lumber contains similar information.

As for the regulatory framework, we can highlight such documents as GOST 2695-83, GOST 26002-83, GOST 8486-86, GOST 9302-83, GOST 8486-86, GOST 24454-80; among the more modern ones, GOST R 1.0 can be noted - 2007. In order not to retell the contents of each of the standards, we will limit ourselves to only the main information.

Types of coniferous wood, or rather the requirements for them, are specified in GOST 8486-86. The following features of dividing wood into classes can be identified:

• It is recommended that manufacturers divide bars and boards into 5 grades (classes or groups may be mentioned). The bars are divided only into 4 classes;
• roughness (that is, the maximum value of irregularities on the surface of the wood) should not exceed 1250 microns for grades no lower than 3, but for grade 4 the tolerance is increased and is already 1600 microns;
• As for humidity, up to the 3rd inclusive it should not exceed 22%. For the 4th, this indicator is not standardized at all;

In production, as a rule, wood is dried

Pay attention! It is possible to produce not only dry lumber, but also wet antiseptic lumber. Such options are possible only by agreement with the customer.

Wood varieties 1 2 3 4 differ not only in the listed characteristics; special emphasis is placed on the number and type of defects. In GOST this classification is given in tabular form.

Here are some excerpts from the standard:

• for example, a defect such as knots is classified into healthy, partially fused and rotten. For selected wood class, the number of knots is limited to 1 (edge ​​knot) and 2 (face knots);

Pay attention! For beams, the number of knots is not regulated.

• For selected wood, even such an indicator as the inclination of the fibers is standardized. If this indicator exceeds 5%, then the grade is set not to selective, but to 1st;
• defects such as sprouting, rot, and discoloration due to infection by various fungi are also not allowed for selected wood.

Photos of some types of defects

Based on the norms given in the standard for the compliance of wood with a certain grade, it is possible to fairly accurately determine the type of wood.

More information about varieties, assortments and assortments of wood

In reality, of course, when choosing lumber in a warehouse, no one recalculates the number of knots or checks for cracks and other defects; in this matter, you will have to rely entirely on standard control. Also, when choosing, you need to clearly understand the range and type of lumber.

How to choose the right variety

An untrained person may be confused by the fact that instead of numbers, letters can be used to indicate quality, for example, wood grades A B C, just as in the case of a digital designation, they mean the division of wood depending on the number of defects.

For example, consider lining of different classes:

• if larch was used for production, then the extra class indicates that there are no defects at all;
• grade A - the maximum you can count on is no more than 1-2 small ingrown knots per 1 board;
• B – on average 1-2 knots for every meter of board length;
• C – the number of knots is not limited at all; for this quality, only the presence of fallen knots is considered unacceptable;
• economy class - the price of this option is minimal, in addition to any number of knots (including fallen ones), flaws in the processing of the board are also allowed.

The number of knots clearly shows the differences between different varieties.

In general, letter marking largely depends on both the manufacturer and the wood. For example, when using Angara pine, the division into grades will look slightly different: in addition to the almost ideal extra-class, you can distinguish grade A (no more than 2-3 knots on the board) and grade B (maximum 4-6 knots).

When choosing, you may encounter another way of designating wood types:

• extra or selected variety can be indicated either by the number “0” or by a simple horizontal line;
• the first is the number “1”; the designation can also be used with one dot or a vertical line;
• the second – respectively the number “2” or 2 vertical stripes or dots;
• third - 3 stripes, 3 dots or the number “3”.

So the selection instructions simply boil down to looking for markings on the tree.

The only thing you need to know is which variety is best suited for solving which problems:

• Grade 1 can be considered the standard of quality. It is these lumber that are recommended to be used for the most critical structural elements, for example, for making a frame. For the production of structural lumber, only hard grades of wood are used;
• 2 – used for less critical tasks, for example, for flooring, wall cladding;
• 3 – suitable for elements that do not experience heavy loads;
• 4 – the maximum that such wood can be used for is making containers and other small items useful in the household.

Lumber with different types of defects

Assortment and assortment

These concepts are almost identical and are used to classify lumber. Wood assortment is the division of lumber into groups mainly depending on size. For example, a board can be made from different types of wood, with different treatments, but in terms of its assortment it will remain a board, but the quality can vary greatly (see also the article “How to make a stool from wood with your own hands: the material used and tools. Preparation and manufacturing process").

The classification of lumber was given above; it can only be noted that within the same type, the wood assortment provides for the existence of several standard sizes. The grade of the product may also differ depending on the processing method, storage conditions, etc.

In the GOST 24454-80 standard you can find out the dimensions of some types of lumber (in particular boards and beams). It can be noted that their length should be in the range of 1-6.5 m in increments of 0.25 m.

As for the section sizes, for example, the range of wooden beams provides for sections from 60x75 to 250x250 mm. But the minimum thickness of the board is 16 mm with a maximum width of 275 mm.

In conclusion

The division of lumber into grades is very convenient. Given the responsible work of quality control in production, it becomes very convenient to choose the appropriate wood to solve any problem - just select the desired class (variety) of wood.

In this article we are talking about ways to eliminate minor shortcomings of lumber.

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