For construction, lumber made from natural wood is often used. They can be classified according to the type of wood, the shape of the workpiece and other parameters. The characteristic of lumber depends on a number of properties of a particular type of tree.
Lumber classification
Each type of wood has its own properties. That is why it is customary to observe a convenient and understandable classification. All natural wood materials can be roughly divided into several groups:
- The bars are mostly rectangular in shape. The characteristic of such materials implies that the division in the group is carried out according to the form, the method of manufacture, and the size of the section. The section is usually made from 100 mm and more.
- Boards can be divided into edged / unedged, sawn. The last group is divided into clean-cut, with a blunt wane (blunt and sharp).
- Rivets are used for barrels. The group is limited, includes rivets with a cylindrical or blunt section.
- Planks and slats, sleepers are materials that are small in size, with a rectangular cross-section. Their thickness and shape may differ slightly.
- Reiki is an unedged board, the edges of which are processed. Three sides of the board are not sawn, and one is sawn.
Lumber classification and characteristics:
- By type of surface treatment. Lumber can have wide surfaces (faces), narrow (edges), end (ends). In turn, wide can be divided into external and internal.
- By the type of sawing wood. With respect to annual rings, lumber is classified into radial, tangential, mixed.
- By type of wood. All lumber can be made from different types of wood, each of which is best suited for a specific purpose. Pine is the leading one in this area; it can be used to make various types of products, including for wall cladding, roofs. Spruce, larch, cedar, fir are used in construction. They are all great for planks. But ash, oak, mahogany are applicable for the manufacture of finishing materials, as joinery, where they fully reveal their qualities. Aspen is excellent for decorating the interior walls of saunas or steam rooms, it perfectly resists the negative effects of moisture, sudden changes in temperature. For parquet boards and natural parquet, experts recommend using birch. Here she fully reveals her potential.
Before purchasing this or that type of lumber, it is necessary to study their characteristics, areas of use. In this case, the selection will be correct, and the wood itself will last a long time.
Wood options
Lumber used for construction can be made from various types of wood. The most popular material is pine needles, most beams and planks are made from pine and spruce, but there are other options. Pine, unlike other types of wood, is lightweight; during construction, minimal loads are placed on the foundation. For example, aspen or birch are very heavy, but their strength characteristics are not so good. Planks are usually made of pine, this material is very durable, easy to process, has many advantages.
Pine contains natural resin, which acts as an excellent antiseptic. This ensures that there are no traces of rot, mold for a long time. Pine has a soft and delicate texture, which makes processing simple, pleasant and fast. The smell and color of pine add attractiveness to the material not only as a standard building material, but also as an option for decorative wall cladding and the construction of log cabins.
The characteristics of lumber are not complete without such parameters as the number and presence of branches. Here you need to pay attention to the spruce. This coniferous species has many positive characteristics, but its processing is difficult. The problem is that the trunk contains many branches, which is an obstacle to processing. Spruce is not as resistant to rotting as pine, but its price is much lower.
Wood such as cedar can also be used for planks. This option is not common, but it is still used.
Cedar wood is strong, reliable, like spruce, but easier and more convenient to process. Fir can also be used for the manufacture of lumber. It is resistant to decay, excellent handling and numerous benefits.
Types of lumber
Lumber is produced in various ways, it is possible to choose a suitable option. Products differ in shape, size, their characteristics, area of use. Common materials include edged and unedged boards, which are acceptable for almost any job, but there are other options that act as auxiliary materials.
Most often, edged and unedged boards are used for construction work, they differ in a number of parameters. These lumber are very popular, they are used for the construction of house frames, for the device of strips, walls, partitions, for the installation of truss systems, formwork and other works.
Edged board is a material obtained by sawing a log. At the same time, all its edges are smooth, but a small amount of bark may remain, that is, wane. Indicators of moisture resistance, strength, mechanical stability are very different, as well as cost.
This makes it possible to choose exactly the material that is more suitable for the work than others, without overpaying. For the manufacture of edged boards, pine or spruce is more often used. The cost of such boards is not so high, but the strength and durability correspond to all parameters. From such boards, you can safely erect not only outbuildings, but also to carry out interior decoration. The lumber has a standard size of 6 m, but the thickness and width are different. The width of the boards can be equal to 100 mm, 150 mm, 200 mm, for the thickness - 25 mm, 40 mm, 50 mm.
The scope of the edged board is quite wide:
- for the manufacture of a frame, walls, partitions;
- to perform flooring of rough, finishing floors;
- for the manufacture of various load-bearing structures;
- for the manufacture of formwork;
- in the manufacture of furniture;
- in the manufacture of carved furniture;
- in the construction of gazebos, garages, sheds, fences.
Unedged board has edges with bark, it is used quite often in construction. The appearance of these lumber is attractive, as close to natural as possible, which makes them an excellent option for wall cladding. Unedged board has a not so high density, therefore it is easy to handle any kind of processing. Finishing with such boards does not take much time. But if there are many cracks on the surface, then this will significantly reduce the life of the lumber.
Four-edged and clear-edged cant
Lumber can vary in price and quality. The cheapest one can be attributed to a four-edged beam, which is manufactured in large quantities, without requiring large costly capacities for this. The production of timber is carried out by sawing or cutting solid wood, but the surface quality will differ significantly. For example, when cutting, the sides are torn, which is not always acceptable. When sawing, the edges and ends are more accurate, such a bar is already suitable for work where the appearance of the materials is important.
A clear cut bar is a square material that is cut from all sides. Its length is usually 4 m, thickness - from 100 mm, depending on the purpose. Such a bar is made, as a rule, from pine. It is machined from all sides, including the end pieces. It is used most often for the construction of house walls, beams, ceilings, subfloors. Differs in high strength properties.
Half-edged board and slab
A half-edged board has uneven planes, traces of bark may remain at the ends. Such a board is used for technical work. Walkways are made of it, it can be used for technical and subfloors, as a basis for other products.
The croaker is a fairly cheap lumber, which, when properly processed, perfectly replaces other wood products.
In appearance, the slab is very similar to the sidewall of a log, part of it is propylene on one side, but not on the other. Such lumber is considered a lump-type waste, they remain after cutting the main material. But the dimensions of the slab are normalized, it has the same width at the ends and along the entire length. Today, two types of slab are used - wood and business material. It is used for various purposes, as blanks for other products and building elements.
Sawn timber is made from natural wood. All of them differ in shape, their individual characteristics, sizes, appearance, degree of processing. Lumber is used for construction and repair work of various types, often used in the assembly of furniture, fences, in the construction of subfloors. When choosing, you should focus on those properties that are necessary for specific conditions.
Today, almost any branch of the national economy uses wood products for different purposes. This is due to the unique properties of this material. Synthetic products are not yet capable of replacing it. Therefore, it produces a variety of types of lumber.
Their properties and classification deserve detailed consideration.
Main characteristics
Wood products are made by sawing. This is where the name comes from. The demand for this material is due to its availability and a number of unique qualities. The existing types of sawn timber are very diverse. They are environmentally friendly and aesthetically pleasing. In addition, they are durable, characterized by a long service life.
However, wood also has negative features. If lumber has been improperly processed or used in unfavorable conditions, their rotting and destruction may occur.
In the selection process, it is necessary to pay attention to the quality of their processing. If the wood has been poorly dried, it will deform. Therefore, you should know what properties each type of product has.
Classification
There are many signs that divide the main types of lumber into groups. The most popular is the classification according to the type of cut:
- Board.
- Bar.
- Bar.
- Sleeper.
- Croaker.
There are also edged and unedged materials. In the first case, the workpiece is processed from all sides, and in the second, only from one side. There are mixed varieties of them.
According to the cutting method, radial and tangential blanks are distinguished. This classification depends on the positioning of the cut relative to the tree rings.
Another important classifying factor is humidity. Dry materials have this indicator at the level of 8-10%. Such products are solid, used for furnishing, for example, flooring. Universal sawn timber has a moisture content of 12-15%. These are blanks for skirting boards, platbands, timber. External lumber has a moisture content of over 18%. They are suitable for cladding the facade, creating a rafter system.
Material
The first type is a lightweight but durable product. It is made most often from tropical woods. The window sill board has a special impregnation and is characterized by good drying. Engineering varieties have a bottom layer of plywood, and the top is made of natural wood.
Lining
One of the most popular types of boards today is lining. These types of lumber are used for indoor and outdoor cladding. Even in technical documents, this type of product is called a sheathing board.
The profile of the lining can be different. The material from which it is produced is also characterized by a wide range. When choosing it, the operating conditions are taken into account. Coniferous and soft deciduous species are suitable for dry rooms.
If this is a bathhouse, then the use of resinous types of wood is not allowed. Otherwise, you may get burned. They are used for street cladding. They are treated with various substances to extend the service life.
Sleepers, small molding
In addition to the products considered, such types of lumber as sleepers, as well as small moldings, are in demand today. These are narrowly focused products, but their importance can hardly be overestimated.
Wood sleepers have a number of advantages when compared with reinforced concrete varieties. They dampen train vibration well and hold the rails securely.
The need for regular maintenance of existing communication lines, as well as the installation of new lines, require a large number of high-quality sleepers. They are made from expensive types of wood, because sleepers are exposed to heavy loads and adverse environmental influences. They are impregnated with special substances in order to avoid decay processes, rapid destruction. Sleepers of different strength classes are used depending on the type of trains moving along the communication line.
Also narrowly targeted varieties of sawn timber are small molded products. These include skirting boards, corners, platbands, glazing beads. They are produced in various dimensions. This allows you to choose the best option for everyone.
Croaker
In the process of making timber or boards, a slab is obtained. This is the side of the log. On the one hand, these lumber is convex, and on the other, it is flat.
This material is also in demand today. For the arrangement of temporary buildings, technical premises, the slab is quite applicable.
Also today it has become quite popular to carry out decorative finishes using this type of lumber. The croaker is mechanically processed only from the single-sided side, therefore, before installation work, it is imperatively impregnated with a special antiseptic. Otherwise, after a couple of years, the croaker will turn into dust. The relatively low cost makes it in demand. New areas are emerging in which this material is applied.
Dimensions (edit)
The types of lumber and their use determine the size. Each type of processing has its own clearly defined shape boundaries. Dimensions sometimes even determine the name of the product. A board is an edged product, the width of which is greater than double thickness.
If this ratio is not met, the product is called a bar. Its width is less than double the thickness. And the bars generally have the minimum specified dimensions. Their thickness and width must exceed 100 mm.
The usual one is 6 m. The standard width and thickness parameters are 100 by 100 mm, 100 by 150 mm or 150 by 150 mm. If the project requires the use of a material with even larger dimensions, the product is made to order. But the cost will be much higher than the standard one. Therefore, when developing a project, the engineer must take these dimensions into account.
The board is also produced in accordance with the standards. Its thickness is 25, 40, 50 mm. The length is usually 4, 5 or 6 m and the width is 100 or 150 mm. The bar is usually made with standard dimensions of 40 by 40 or 50 by 50 mm. The length of the workpiece can be 3, 4, 5 or 6 m.
For the arrangement of flooring, a certain type of boards is produced today. They are 85 to 140 mm wide. Depending on the load level, its thickness ranges from 27 to 45 mm. Standard dimensions must be taken into account in the design process.
Having considered the main types of sawn timber, their properties, scope, everyone can choose the best type of product for their conditions. The variety of shapes, sizes and materials allows them to be used in almost any field of human activity.
Lumber- timber obtained as a result of longitudinal sawing of logs and ridges.
Depending on the type of wood, they are divided into coniferous and deciduous.
Lumber as a structural, finishing, cladding and roofing material, as well as a material for the manufacture of joinery and molded products and sleepers is used in residential, industrial and railway. construction.
Lumber includes: plates, quarters, planks, bars, beams, sleepers and slabs.
Plate
Plate obtained by sawing a log along the axis into two equal parts - halves. The plates have sawn off only one side. They are used for the manufacture of sleepers, joinery, boards, bars, etc. The sizes depend on the logs.
Quarters
Quarters obtained by sawing a log in two mutually perpendicular directions or by sawing a plate into two equal parts. They are used for the manufacture of joinery, moldings and other small products. The dimensions depend on the dimensions of the logs or plates.
Planks
a - edged; b - unedged; c - with sharp wane; d - with blunt wane; d - grooved
Planks - a type of lumber, in which the width exceeds the thickness twice or more. Obtained by longitudinal sawing of logs along several parallel planes. The thickness of the boards is from 13 to 100 mm, the width is from 50 to 260 mm. Boards with a thickness of 13 to 35 mm are called thin, the rest are thick. The wide sides of the boards are called planks, the narrow sides are called edges. According to the processing of the side edges, the boards are divided into edged ones, in which the edges are sawn and unedged, the edges of which are not sawn at all are sawn off less than half the length. Hardwood boards are produced, as a rule, unedged. Edged boards, in which the lateral surface of the log remains on the edges, are called wane boards. Sagging is sharp when the edge is not completely sawn in thickness, and dull when the edge is partially sawn. By the nature of the surface treatment, the boards are divided into untreated and processed. Untreated boards after sawing the logs are not subjected to additional processing. The boards processed after sawing are subjected to additional processing (planing, grooving, etc.). They are divided into planed and grooved. Planed boards - the surface of which is planed on one, two, three or four sides. The boards are grooved - on one edge they have a tongue (groove), and on the other - a ridge (protrusion), which enters the tongue of another board. For planing, planing, thicknessing or four-sided planing machines are used. The planer is used for planing parts from two adjacent sides; thicknesser - for planing parts parallel to the planed side to a given thickness; four-sided planer - for simultaneous planing from two or four sides. Untreated boards, depending on wood defects and processing, were divided into varieties: from conifers - into selected, 1st, 2nd, 3rd, 4th and 5th; from hardwood - on the 1st, 2nd, 3rd and 4th. Planed and grooved boards were divided into three grades: 1st, 2nd, 3rd. Defects of processing included: wane, mossy and wavy cut, curvature, non-parallelism of seams, edges, etc. The norms of defect tolerances by grade were regulated by GOST 8486-57 for boards made of coniferous species and 2695-56 for boards made of hardwood. Coniferous boards were used: selected, 1st and 2nd grades - for structures, manufacture of joinery, furniture, platbands, clean floors; 3rd and 4th grades - for the installation of subfloors, lathing, interroom partitions; 5th grade - for temporary warehouse and outbuildings, for the manufacture of picket fence and other small products. Hardwood boards were used: 1st and 2nd grades - for clean floors, for the manufacture of molded, joinery and furniture; 3rd and 4th grades - for interroom partitions and temporary structures. Planed and grooved boards of all grades were used for clean floors, wall cladding, ceilings; grooved, in addition, in cases where it is necessary to obtain a strong and dense non-translucent connection of individual boards. Thin boards were used for roofing, wall cladding, clean floors, between room partitions. On the front side of the roofing boards, there should have been grooves at the edges for water drainage.
Bar
Bars- lumber, in which the width is not more than double thickness, and the thickness itself does not exceed 100 mm. Available in the same thicknesses, lengths and types as the boards. The division into grades and quality requirements are the same as for boards. They were used for structures, for the manufacture of joinery, furniture, clean floors.
Beams
a - two-edged; b - four-bit; I am wane
Bars- lumber, the width and thickness of which is over 100 mm. They are made mainly from coniferous and hard deciduous trees (pine, spruce, cedar, fir, larch, oak, hornbeam, etc.). The thickness of the beams is from 110 to 240 mm, the width is from 110 to 280 mm, the length is from 1 to 9.5 m with a gradation of 0.25 m.By the nature of the processing, the beams are divided into two-edged - sawn from two mutually parallel opposite sides and four-edged - sawn from four sides. In terms of cleanliness, filings can be the same as boards, without wane and with blunt wane. According to the presence of defects in wood and processing, they are divided into 1st, 2nd, 3rd, 4th and 5th grades. Used: 1st and 2nd grade - for agricultural. mechanical engineering and railway bridges; for supporting structures and parts, for racks, beams and intermediate floors; 3rd and 4th grade - for bar walls of residential and public buildings, floor logs, etc.; 5th grade - for processing into small workpieces and parts of products at the site of lumber production.
Sleeper
a - edged "A"; b - squared and squared "B"
Sleepers- lumber of large width and thickness and short length. Produced from coniferous logs. They are used for the railway device. canvases. By purpose, they are divided into two types: for a wide track and for a narrow track. Sleepers for a wide track have a length of 270 cm (sometimes 250 cm), a width (along the bottom layer) from 215 to 250 mm and a thickness from 135 to 175 mm. There are two types: edged "A" - sawn off from four sides - sawn off from two opposite sides. Each of the types, depending on the type of rails for which it is intended, is divided into five types: edged - IA, IIA, IIIA, IVA and VA; squared - 1B, PB, P1B, 1B and VB. The types differ from each other in the thickness and width of the upper and lower edges. According to the quality of wood and processing, they were divided into three grades: 1st, 2nd and 3rd (GOST 78-40). Sleepers of the 1st grade of the first three types (I, II, and III) are used for main-line railways. lines; 2nd grade of the first three types and 1st grade of IV and V types - for station tracks, secondary lines and lines of industrial enterprises; 3rd grade of all types and 2nd grade. IV and V types - for railway industrial transport routes. Sleepers for a narrow track have a length from 150 to 180 cm, a width (along the bottom surface) from 19 to 26 cm and a thickness from 11 to 14 cm. They are divided into slabs, sawn from two or four opposite sides, and plate ones, obtained from plates. According to the cross-sectional shape and dimensions, they were divided into five types. Sleepers of types O, I and III - bar; II and IV - plate. For a track width of 750 mm, taps of types I, II, III and IV are used; for 1000 mm track - O, I and II types.
Croaker
Croaker- the side part of the log. It turns out in the form of waste when sawing logs into boards. The slab has sawn off only one side, on the other - the oval surface of the log is preserved. It was used for the construction of the lathing under the roof, for the construction of temporary and auxiliary buildings for the manufacture of a picket fence, etc.
Sawing of logs and logs into lumber is carried out on saw frames, circular saws and band saws. The main working part of the LRB-75 sawmill frame is a frame in which the saws are vertically mounted. Up to 14 saws can be inserted into the frame, depending on the thickness of the log and the specified thickness of the lumber. The frame, receiving from the electric motor a vertical reciprocating movement along the guides, cuts the log along the entire thickness. Special trolleys are used to feed the logs into the sawmill and receive the lumber when leaving the frame. With one pass of the logs through the frame, unedged sawn timber is obtained; with two - edged. Sawing of logs is carried out mainly in two passes in succession on two adjacent timber frames; this increases the yield and improves the quality of the finished product. The productivity of the LRB-75 sawmill in an eight-hour working day with one pass (on unedged boards) is up to 200 m³ of logs; with two passes - it is almost halved. Circular saws have a saw in the form of a thick disc of large diameter (1 m or more) and are mainly used for making sleepers. Most often, a PDT-4 machine was used with a saw diameter of 1200 mm, a speed of 800 and a feed rate of up to 60 m / min.
Band saws have a saw in the form of a thin continuous band rotating on pulleys. The length of the saw band is 11.2 m, the width is up to 250 mm, the thickness is 1.47— 1.83 mm, the speed of the saw (cutting) is 46 m / s, the cutting height is 1220 mm, the feed speed of the log is 60 m / min. They were used for sawing thick logs and logs of valuable wood because they give little waste (narrow kerf). In one pass, only one board was sawed off, which made it possible to more accurately regulate the thickness and monitor the quality.
Lumber was counted in cubic meters according to the tables of GOST 5306-50 with an accuracy of 0.0001 m³ of each assortment and up to 0.01 m³ of a batch. The width of unedged boards was calculated by the half-sum of the widths of the layers in the middle of the length of the board. The width of edged boards was determined by the width in the middle of their length, and boards with wane along the wide side in the edged part. The length of the lumber was expressed in meters; fractions less than 0.25 m for softwood and 0.1 m for hardwood are not taken into account. Lumber was marked individually or in packs with the grade and braker number. The variety was placed with a stamp or indelible chalk on one of the layers, with a jackhammer or indelible paint on the end. When marking with paint, the variety was indicated by the number of dots or vertical stripes (selected variety with a horizontal stripe at the end); when marking with a stamp, jackhammer or chalk - Roman numerals (selected grade with the letter "O"). Lumber for storage was stacked on pads separately by species, grade and nature of processing. The stacks were covered from above with a pitched roof.
Wood has long been known to mankind as one of the best building materials. Its characteristics make it possible to apply it in many areas of the national economy. This material is reliable, durable, endowed with aesthetic qualities. Also, wood is famous for its environmental friendliness. Therefore, the scope of its application is very wide. Various lumber is created from wood, what is their purpose, you should consider in more detail. The variety of types of such products makes it possible to use them on a variety of objects.
general characteristics
Today there are a huge number of different types of lumber. They are obtained by sawing along the grain. All lumber requires proper processing. GOST 8486-86 and 2695-83 are the main ones in the production of such products. However, there are many other standards that govern this industry. Their implementation is a prerequisite in the process of creating quality products.
In addition to its positive qualities, wood is also known for its shortcomings. It is subject to various destructions, decay, and the vital processes of insects and microorganisms. Also, this material can deform under the influence of environmental conditions. To avoid all these troubles, proper handling is required. To understand what lumber is, you need to familiarize yourself with the conditions for their preparation for processing.
Applicable breeds
Each has special properties and is of great importance. Both coniferous and deciduous varieties are used. Their cost depends on the characteristics inherent in the material.
Pine is considered one of the inexpensive. This material contains a large amount of resins. Therefore, it is not used at elevated ambient temperatures. Also, the strength characteristics of pine are quite low.
Larch has good resistance to the influence of fungi, microorganisms and insects. She is not afraid of moisture. It is actively used in almost all areas of construction.
Oak is famous for its beautiful texture. It is very durable, which makes it highly desirable in construction and decoration. Ash is resistant to mechanical stress due to its elasticity. A wood species such as birch is easy to process. Therefore, various elements are made from it, even at home.
The properties of each type of material must be taken into account during processing.
Processing degree
Before sawing, the wood is subjected to additional preparation. It is dried to a certain level. The scope of its application depends on this. If the moisture content of the wood after processing does not exceed 10%, it is dry sawn timber. Parquet, boards, etc. are made of it.
A universal material is wood dried up to 11-15%. Planks for flooring, platbands, baseboards, etc. are made from it. If the material is characterized by a moisture level of 18%, it is used for exterior decoration, arranging the rafter system, etc.
The drying process is carried out in natural conditions or in a chamber at elevated temperatures. Each of these processes requires the correct execution of each operation.
Processing method
There are two main ways to cut a log. It can be radial or tangential. In the first case, the incision runs towards the center of the growth rings. In this case, the bars are of different sizes. Their width is limited by the diameter of the tree itself.
The tangential incision is directed tangentially to the growth rings. This allows you to get the output of many fragments of identical cross-sectional shape and size.
All deciduous and coniferous lumber is divided into unedged, planed or edged. In the first case, there are untreated areas on the product, which are only freed from bark and knots.
The trim materials have a saw cut parallel to each other. This is a rectangular shape of the products. Planed products from at least one surface do not have roughness. They are planed.
Cut type
According to the shape that the product acquires after processing, there are several types of lumber. The area of application depends on their dimensions. Both softwood sawn timber and deciduous wood have features of the form.
The first in the presented classification is the bar. Its thickness is over 100 mm. This is one of the most demanded lumber. Boards, on the other hand, are limited in thickness. This characteristic does not exceed 100 mm.
The bar has a thickness of no more than 100 mm. But for this product, one more parameter is important. Its width should be less than double its thickness.
Obapol has a saw cut only on one side. In this case, the width can be different. Also recently, for decorative purposes, they began to use such a type of lumber as a croaker. This is an intermediate option between the obapol and the board. It has only one flat plane. On the other hand, its surface is untreated and has a regular semicircular shape. Also, various types of sawing include clapboard, block house, planken and logs.
Varieties of sawn timber
Studying what lumber is, one cannot but pay attention to the purpose of each variety. The timber can be glued, ordinary, windowed or imitated. There are wane products related to this type. Their cross section is at least 120 x 120 mm. They have a cut at the thin end. It is not less than 1/3 of the side of the bar.
The board is floor, deck, terrace. For each application, it is treated accordingly.
The bar can be regular or planed. The rest of the lumber varies in size and shape. The scope of their application can be different. They are used both indoors and outdoors.
It should also be borne in mind that the length of the cut of wood should not exceed 5 m for hardwood, and 6.5 m for conifers. The area of application in the construction business depends on their dimensions and features.
The use of softwood lumber
Coniferous wood is usually soft and light. But there are also quite strong, heavy representatives of this group (for example, yew). This material has resin passages and a fairly large number of knots. It is cheaper
Softwood lumber is used in joinery and construction. But most often these materials are suitable for finishing dry rooms with normal temperature conditions. For outdoor work, such wood is treated with special impregnations.
Hardwood application
Most often, hardwood lumber has a high hardness. They are denser, heavier than conifers. Such materials are less susceptible to adverse environmental influences. Therefore, their cost is quite high.
Hardwood lumber is used to create rafters, flights of stairs inside a private house, wall cladding and partitions in rooms, as well as for ceilings.
Linden, poplar or birch are not used for supporting structures or finishing floors. They are soft and lightweight.
Having familiarized yourself with the concept of what lumber is, what their types are, you can navigate in the purpose of the products. Today there are a huge number of them.
H To move on to a more detailed consideration of sawn timber processing, you need to familiarize yourself with the following terminology. These are elements of lumber.
The lumber face is the longitudinal wide side.
Lumber edge is the longitudinal narrow side.
Lumber edge is the intersection of the edge and face.
Lumber end is the end cross-section.
For processing, lumber is divided into edged, unedged, one-sided edged. Edged lumber is called lumber with four processed sides. Wane is allowed in permissible dimensions (wane is the surface of the log).
Unedged lumber is called lumber with a side surface of a log instead of an edge. One-sided edged lumber is called lumber that has sawn faces and one edge. The shedding is admissible within the limits of GOST. They also distinguish between the degree of processing of lumber. They are planed and non-planed.
In addition, depending on the location in the log, lumber can be core, central, side. By the nature of processing, lumber is divided into unedged, edged and one-sided edged. Lumber that has a lateral surface of a log instead of edges is called unedged(Fig. 2 a); lumber, in which all four sides are sawn, and the amount of wane (the part of the surface of the log that remains on the lumber) does not exceed the permissible dimensions, is called edged(Fig. 2 b). One-sided sawn timber has sawn faces and one edge, and the size of wane on the sawn edge does not exceed the permissible values. In the direction of the length of the board, a butt (wide) and apex (narrow) butt are distinguished. The flab occupying part of the edge width is called blunt (Fig. 2 c), the entire width of the edge is sharp (Fig. 2 d). According to the degree of processing, lumber is divided into non-planed and planed. Depending on the purpose, planed lumber has a different cross-sectional shape. By the location of the lumber in the log (in relation to the longitudinal axis), core, central and side boards are distinguished. Pith lumber contains the largest number of knots and is prone to cracking. Such lumber is not of the highest grade. The central lumber cuts through all annual layers and is therefore of a higher quality. Side boards are sawn between the core (or center) and slab. They have a cleaner surface, easy planing, and generally have better quality.