Everything you need to know about board grades

The grade of edged and unedged wood products directly depends on the strength characteristics and quality of the state of the products themselves. This parameter is used to simplify the selection of a specific type of board for a particular job.

The range of wood includes a number of important characteristics that affect the belonging of a product to a certain category.

• The size. GOST establishes special standards for the size of edged boards, the moisture content of which does not exceed 20%. This means that due to material shrinkage, the thickness and width parameters are less or more than the norm.

• Moisture percentage. Woody material that has a moisture content of 22% is generally considered dry. This degree is considered normal for the first 3 varieties, as well as for the selected variety of wood. The difference between the 4th grade product is that moisture indicators are not recorded.

• Disadvantages of natural origin. This is a very important point when choosing a tree, since the presence of flaws on the product will directly indicate its grade. Knots can be fused in whole or in part. Sometimes, when knots that have not grown together fall out, a hole appears to be sealed. In turn, knots have their own classification. They are rotten, rotten, tobacco and normal (in a healthy state). If the tree decays completely, it means that the twig is tobacco. Wood material should also be checked for cavities between the annual layers that are filled with resin. If the product contains so-called pockets, then their number should not exceed the established standards. The existence of flaws of the tobacco and rotten types is not acceptable on the first class product.

• Fungal lesions. Sometimes they appear on the material itself, forming blue mushroom spots or rot. Within the bark, they can be present in products of the lowest grade, but this is undesirable.

• Wrap. A sharp-looking shed can take up the entire width of the board, and a blunt-looking one - only partially the width of the edge.

• Warping. If the moisture content of the edged board changes, then it begins to bend. The bend can be calculated from the ratio of length to width. These norms, as a rule, can be reduced by 2 times in the event that the percentage of moisture in the edged board is above 22%. If the wood is of the highest quality, no roll is allowed on it.

• Cracks. During the drying process, crevices, defects and tears appear on the wood. Cracks are not considered significant if the depth does not exceed 5 millimeters. Through-type crevices appear on the sides or at both ends. Cracks are edge and reservoir. The presence of such cracks may be within the limits of the norms. GOST also classifies cracks according to the size of the deepening.

The classification includes 5 types of planed boards, including the highest grade. Each one has significant differences. Below are descriptions of each of them.

This is one of the highest quality dry edged boards.

They are used for finishing the interior of buildings and premises, used in furniture production, as well as in the construction of navigational elements, for example, deck parts or yacht masts, in the automotive industry. The most expensive class, which is conifers.

Maximum permissible size of cracks: 16% in relation to the length of the board, no more than 10% in relation to the depth. The deflection cannot be more than 1%. It is rather difficult to find a board of this type among the products of the domestic construction market, since it is exported abroad.

This is sometimes referred to as grade zero lumber. These boards are free from defects caused by rot, do not have through holes, remains of the vital activity of parasites, mold elements. On wood of this type, there can be no knotty formations, cracks, cracks and flaws from shrinkage, as well as bark residues. They, as a rule, look great, ideally shaped, smooth, without irregularities and roughness, which makes them different from other varieties.

However, there are a number of reasons why such material is practically unavailable.

• The highest requirements are imposed on the grade of "zero" class. It is usually an export material as well as a material for high-end construction projects.
• The cost is much higher than that of other types of wood.
• Due to the difference between domestic and foreign measures and weights, as well as the production of a product for export, when used in Russia, there may be certain dimensional inaccuracies.

Among the wood products of the "zero" class, one can find such as lining, floorboards, imitation of timber, boards for a deck or terrace, planken and others.

Top-notch products are quite sought-after and salable. They contain the minimum number of cracks, knotty formations and other shortcomings. Naturally, on the boards of the first grade, the minimum amount of damage from rot, mold and parasitic defects, fungal spots, blue stain and others. A single number of defects is allowed.

Defects caused by fungal infection cannot be more than 10% of the entire surface. Rot is unacceptable. A small wane of a blunt type is allowed. Extra-class curvature. The moisture content of the material is no more than 20-22% with an error of 3%.

The integral state of the first-class edged board does not change. Such a product is intended for frame, staircase, door, frame and assembly types of construction.

Second-class products include products that have minor flaws. These flaws should not spoil the appearance of the product. Deep cracks, rotten knots and rotten formations are prohibited. Knots can be loose, no more than 20 mm in diameter. Blueness and moldy parts occupy up to 20% of the surface.

The area of ​​application of products of this kind is very, very wide, because it has the most comfortable price-quality ratio. From this class of wooden materials, you can build shields, work with crate.

Third-grade lumber of inferior quality compared to other grades. Basically, they make box-shaped products for packaging, some types of containers, pallets and flooring. The only requirement for them is the absence of large knots, completely fused together, as well as large and bulky cracks.

Trimmed third-grade board products may have a moisture frame that is of the first and second grade. It is important that outwardly there may be certain flaws, and in general there may be quite a few of them. However, in no case should there be rotten formations.

The cheapest class of lumber, which involves a large number of defects. Permissible defects: roughness, general putrefactive damage, intergrown knots, presence of mold. Such boards are usually used for making containers, in rough construction work, in the production of boxes and other things. And also they are often used for the construction of temporary fences and barriers, sheds and utility blocks.

To correctly select the right grade of lumber, you can learn to identify it with a few helpful tips.

• It is necessary to take into account the presence of annual rings. In the area of ​​vertical dissection, such rings are close to each other. In this case, the edged lumber will be durable and resistant to moisture. Wood is of better quality if it is grown in colder climates.
• The edged tree should not have a core. Such a part can be a harbinger of fungal infections.
• When choosing materials, be careful: you do not need to take edged boards that are too dry, as well as those that contain a large amount of moisture. You need to pay attention to the conditions of their storage.

Each variety has the most preferred application.

• Grade 1 - the construction of frame elements, and is also suitable for the construction of large-scale objects. For this type of activity, it is better to use larch.
• Grade 2 - floor coverings, as well as panel surface cladding.
• 3 - structures that do not require significant loads.
• 4 - suitable for containers, lathing, fences.