For construction, lumber made from natural wood is often used. They can be classified according to the type of wood, forms of workpiece and other parameters. The characteristic of lumber depends on a number of properties of a particular type of tree.
Timber 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 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, method of manufacture, and the size of the section. The cross section is usually made from 100 mm or more.
- Boards can be divided into edged / unedged, sawn. The last group is divided into clean-edged, with a blunt wane (blunt and sharp).
- Staves are used for barrels. The group is limited, includes rivets with a cylindrical or blunt section.
- Planks and planks, sleepers are materials that are small in size, rectangular in cross section. Their thickness and shape may vary slightly.
- Reiki is an unedged board, the edges of which are processed. Three sides of the board are unsawn and one side is sawn.
Timber classification and characteristics:
- By type of surface treatment. Lumber can have wide surfaces (plasti), narrow (edges), end (ends). In turn, wide can be divided into external and internal.
- Like sawing wood. Regarding 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 specific purposes. Pine is the leading one in this area; various types of products can be made from it, including for wall and roof cladding. Spruce, larch, cedar, fir are used in construction. All of them are great for boards. But ash, oak, mahogany are applicable for the manufacture of finishing materials, as joinery, where they fully reveal their qualities. Aspen is great for finishing 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 one or another 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 that is used for construction can be made from various types of wood. The most popular material is needles, most of the bars and boards are made from pine and spruce, but there are other options. Pine, unlike other types of wood, is light in weight; during construction, minimal loads are placed on the foundation. For example, aspen or birch have a very large weight, but their strength characteristics are not so good. Planks are usually made from pine, a material that is very durable, easy to work with, and has many advantages.
Pine in the composition contains natural resin, which acts as an excellent antiseptic. This ensures the absence of traces of rot, mold for a long time. Pine has a soft and delicate structure, which makes processing simple, pleasant and fast. Smell, pine color add attractiveness to the material not only as a standard building material, but also as an option for decorative wall cladding, construction of log cabins.
The characteristics of lumber are not complete without such a parameter as the number and presence of branches. Here it is necessary to pay attention to spruce. This coniferous breed has numerous positive characteristics, but its processing is complicated. The problem is that the trunk contains a lot of branches, and this is an obstacle to processing. Spruce is not as resistant to decay as pine, but its price is much lower..
For boards, wood such as cedar can also be used. This option is rare, but still used.
Cedar wood is durable, 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, perfectly processed, has numerous advantages.
Types of lumber
Lumber is available in a variety of sizes, so you can choose the one that suits you best. Products differ in shape, size, their characteristics, areas of use. Among the common materials are 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 installation 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, a wane. Indicators of moisture resistance, strength, mechanical stability are very different, as well as the 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 are most often used. The cost of such boards is not so great, but the strength and durability correspond to all parameters. From such boards, you can safely build not only outbuildings, but also carry out interior decoration. 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 thickness - 25 mm, 40 mm, 50 mm.
The scope of the edged board is quite wide:
- for the manufacture of frames, walls, partitions;
- for flooring of draft, 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;
- at construction of arbors, garages, canopies, protections.
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, so it can be easily processed in any way. Finishing 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 clean-edged timber
Lumber can vary in price and quality. The cheapest can be attributed to the four-edged timber, which is manufactured in large quantities, without requiring large costly capacities. The production of a bar is carried out by sawing or hewing an array of wood, but the surface quality will differ significantly. For example, when hewing, the sides turn out to be torn, which is not always acceptable. When sawing, the edges and ends are more accurate, such a beam is already suitable for work where the appearance of materials is important.
A clean-cut timber is a square-section material, planed on 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 processed from all sides, including the end parts. It is used most often for the construction of the walls of the house, beams, ceilings, subfloor. Differs in high strength properties.
Semi-edged board and slab
The semi-edged board has uneven planes, traces of bark may remain on the ends. This board is used for technical work. Bridges are made from it, it can be used for technical and subfloors, as a basis for other products.
Slab 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, and not on the other. Such lumber is considered lump type waste, they remain after cutting the base material. But the dimensions of the slab are normalized, it has the same width from 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.
Lumber is made from natural wood. All of them differ in shape, individual characteristics, size, appearance, degree of processing. Lumber is used for various types of construction and repair work, often used in the assembly of furniture, fences, and 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 various purposes. This is due to the unique properties of this material. Synthetic products are not yet able to replace 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. That's 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 lumber from wood are very diverse. They are environmentally friendly and aesthetically pleasing. In addition, they are durable and have a long service life.
However, wood also has negative features. If lumber has been improperly processed or used in adverse conditions, their decay 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 warp. 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.
- Slab.
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.
According to the cutting method, radial and tangential blanks are distinguished. This classification depends on the positioning of the cut relative to the growth rings of the tree.
Humidity is another important classifying factor. Dry materials have this indicator at the level of 8-10%. Such products are solid, used for arranging, for example, flooring. Universal lumber has a moisture content of 12-15%. These are blanks for skirting boards, platbands, timber. External lumber has a moisture content of more than 18%. They are suitable for facade cladding, creating a truss system.
Material
The first type is a light but durable product. It is made most often from tropical woods. The board for window sills has a special impregnation and is characterized by good drying. Engineering varieties have a plywood bottom layer, and their top is made of natural wood.
clapboard
One of the most popular types of boards today is lining. These types of lumber are used for cladding inside and outside the premises. Even in technical documents, this type of product is called a sheathing board.
The lining profile may 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 hardwoods 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 their service life.
Sleepers, small moldings
In addition to the products considered, such types of lumber as sleepers, as well as small moldings, are in demand today. These products are narrowly focused in application, but their importance can hardly be overestimated.
Wood sleepers have a number of advantages when compared with reinforced concrete varieties. They dampen the vibration of the train well, securely hold the rails.
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 wood species, because the sleepers are subjected to heavy loads and adverse environmental influences. They are impregnated with special substances to avoid the processes of decay and rapid destruction. Depending on the type of trains moving along the communication line, sleepers of different strength classes are used.
Also, narrowly focused varieties of lumber are small molded products. These include skirting boards, corners, platbands, glazing beads. They are produced in various sizes. This allows you to choose the best option for everyone.
croaker
In the process of manufacturing 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 - 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 perform decorative finishing with this type of lumber. The slab is mechanically processed only from the single-sided side, therefore, before installation work, it must be impregnated with a special antiseptic. Otherwise, after a couple of years, the slab will turn into dust. The relatively low cost makes it popular. There are new areas in which this material is used.
Dimensions
Types of lumber and their application determine the dimensions. Each type of processing has its own well-defined form boundaries. Dimensions sometimes even determine the name of the product. The board is edged products, the width of which is more than double the thickness.
If this ratio is not met, the product is called a bar. It has a width less than twice the thickness. And the bars generally have a minimum set dimensions. Their thickness and width must exceed 100 mm.
The usual one is 6 m. The width and thickness parameters are standardly 100 by 100 mm, 100 by 150 mm or 150 by 150 mm. If the project requires the use of material with even larger dimensions, the product is made to order. But the cost will be much higher than the standard. 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 today produce a certain type of boards. They have a width of 85 to 140 mm. Depending on the load level, its thickness is from 27 to 45 mm. Standard dimensions must be taken into account in the design process.
Having considered the main types of lumber, 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, sheathing and roofing material, as well as a material for the manufacture of joinery and moldings and sleepers, is used in housing, industrial and railway. construction.
Lumber includes: plates, quarters, boards, bars, beams, sleepers and slabs.
plates
plates are obtained by sawing a log along the axis into two equal parts - halves. The plates are sawn on only one side. They are used for the manufacture of sleepers, joinery, boards, bars, etc. The dimensions depend on the logs.
quarters
quarters are 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 carpentry, moldings and other small products. The dimensions depend on the dimensions of the logs or plates.
Boards
a - edged; b - unedged; in — with a sharp wane; g - with a blunt wane; d - grooved
Boards - a type of lumber, in which the width exceeds the thickness twice or more. Obtained by longitudinal sawing of logs along several planes parallel to each other. Board thickness from 13 to 100 mm, width 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 layers, the narrow ones 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 completely unsawn, sawn less than half the length. Hardwood boards are produced, as a rule, unedged. Edged boards, in which the side surface of the log remains on the edges, are called wane boards. The wane is sharp when the edge is not completely sawn in thickness, and blunt when the edge is partially sawn. According to the nature of the surface treatment, the boards are divided into raw and processed. Untreated boards after sawing the logs are not subjected to additional processing. Boards processed after sawing are subjected to additional processing (planing, grooving, etc.). They are divided into planed and tongue-and-groove. Planed boards - the surface of which is planed on one, two, three or four sides. Tongue-and-groove boards - on one edge they have a tongue (notch), and on the other - a ridge (protrusion) that enters the tongue of another board. For planing, planer, planer or four-sided planer is used. The jointer is used for planing parts from two adjacent sides; thickness gauge - for planing parts parallel to the jointed 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 grades: from coniferous species - into selected, 1st, 2nd, 3rd, 4th and 5th; from hardwood - on the 1st, 2nd, 3rd and 4th. Planed and tongue-and-groove boards were divided into three grades: 1st, 2nd, 3rd. Processing defects included: wane, mossy and wavy cut, curvature, non-parallelism of layers, edges, etc. Defect tolerance standards for grades were regulated by GOST 8486-57 for boards made of coniferous species and 2695-56 for those made of hardwood. Softwood boards were used: selected, 1st and 2nd grades - for structures, the manufacture of joinery, furniture, trim, clean floors; 3rd and 4th grades - for the installation of black floors, battens, interior partitions; 5th grade - for temporary storage and outbuildings, for the manufacture of fences and other small items. Hardwood boards were used: 1st and 2nd grades - for clean floors, for the manufacture of moldings, joinery and furniture; 3rd and 4th grades - for interior partitions and temporary structures. Planed and tongue-and-groove boards of all sorts were used for clean floors, wall cladding, and ceilings; tongue-and-groove, in addition, in those cases when 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 boards for the roof on the front side, along the edges, there should have been grooves for water drainage.
Bar
bars- sawn timber, in which the width does not exceed twice the thickness, and the thickness itself does not exceed 100 mm. Available in the same thickness, length 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.
bar
a - two-edged; b - four-bit; I - with a 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 bars 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. four sides. In terms of cleanliness, filings can be the same as boards, without wane and with a blunt wane. According to the presence of defects in wood and processing, they are divided into 1st, 2nd, 3rd, 4th and 5th grades. Were applied: 1st and 2nd grade - for page - x. mechanical engineering and railway bridges; for load-bearing structures and parts, for racks, beams and floors; 3rd and 4th grade - for block walls of residential and public buildings, floor logs, etc.; 5th grade - for processing into small blanks and parts of products at the site of lumber production.
Sleeper
a - edged "A"; b - bar and bar "B"
Sleepers- lumber of large width and thickness and small length. Made from softwood logs. Are applied to the device zh.-d. canvases. According to their purpose, they are divided into two types: for a wide gauge and for a narrow gauge. Sleepers for wide gauge 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 from four sides - sawn 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; bar - 1B, PB, P1B, 1B and VB. The types differ from each other in the thickness and width of the upper and lower plates. 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 railway lines. 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 the railway. industrial transport routes. Sleepers for narrow gauge have a length of 150 to 180 cm, a width (along the lower layer) of 19 to 26 cm and a thickness of 11 to 14 cm. They are divided into bar, sawn from two or four opposite sides, and plate, obtained from plates. According to the cross-sectional shape and size, 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, type I, II, III and IV ties are used; for 1000 mm gauge - O, I and II types.
croaker
croaker- the side of the log. It turns out in the form of a waste when sawing a log into boards. Only one side of the slab is sawn, on the other, the oval surface of the log is preserved. It was used for the installation of roof battens, for the construction of temporary and auxiliary buildings for the manufacture of a picket fence, etc.
Sawing logs and logs into lumber is carried out on sawmill frames, circular saws and band saws. The main working part of the saw frame LRB-75 is the frame in which the saws are vertically fixed. Up to 14 saws can be inserted into the frame, depending on the thickness of the log and the given thickness of the lumber. The frame, receiving from the electric motor a vertical reciprocating motion along the guides, cuts the log along the entire thickness. Special trolleys are used to feed the log into the sawmill and receive the lumber when leaving the frame. With one pass of the log through the frame, unedged lumber is obtained; with two - edged. Sawing logs is carried out mainly in two passes in succession on two adjacent sawmills; this increases the yield and improves the quality of the finished product. The productivity of the LRB-75 sawmill for 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 disk of large diameter (1 m or more) and are used mainly for making sleepers. Most often, a PDT-4 brand machine was used with a saw blade diameter of 1200 mm, a speed of 800 and a feed speed of up to 60 m / min.
Band saws have a saw in the form of a thin continuous band rotating on pulleys. Saw blade length 11.2 m, width up to 250 mm, thickness 1.47-1.83 mm, saw (cutting) speed 46 m/s, cutting height 1220 mm, log feed speed 60 m/min. They were used for sawing thick logs and ridges of valuable wood species because they give little waste (narrow cut). In one pass, the logs were sawn off only one board, which made it possible to more accurately regulate the thickness and monitor the quality.
Lumber was taken into account 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 half the sum of the width 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 a wane along the wide side in the edged part. The length of lumber was expressed in meters; shares less than 0.25 m for softwood and 0.1 m for hardwood are not taken into account. Saw-timbers were marked individually or in bundles indicating the grade and number of the grader. The variety was set with a stamp or indelible chalk on one of the faces, 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 (selective variety by a horizontal stripe at the end); when marking with a stamp, jackhammer or chalk - Roman numerals (selective grade with the letter "O"). Lumber for storage was stacked on linings separately according to species, grades and nature of processing. The stacks were covered with a shed roof from above.
Wood has long been known to mankind as one of the best building materials. Its characteristics allow it to be used 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, its scope is very wide. Various lumber is created from wood, what is their purpose should be considered in more detail. A 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 cutting along the fibers. Proper processing requires all lumber. GOST 8486-86 and 2695-83 are the main ones in the production of such products. However, this industry is regulated by many other standards. Their implementation is a necessary condition in the process of creating high-quality products.
In addition to its positive qualities, wood is also known for its shortcomings. It is subject to various destructions, decay, vital processes of insects and microorganisms. Also, this material can be deformed 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 its own special properties. Both coniferous and deciduous varieties are used. Their cost depends on the inherent characteristics of the material.
Pine is considered one of the inexpensive ones. 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 fungus, 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 popular in construction and decoration. Ash is resistant to mechanical stress due to its elasticity. This type of wood, like 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.
Degree of processing
Before cutting, the wood is subjected to additional preparation. It is dried to a certain level. This depends on the scope of its application. If the moisture content of the wood after processing does not exceed 10%, it is dry lumber. Parquet, shields, etc. are made from it.
The universal material is dried up to 11-15% wood. Floor boards, platbands, skirting boards, etc. are made from it. If the material is characterized by a moisture level of 18%, it is used for exterior decoration, arranging the truss 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 logs. 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 obtained in different sizes. Their width is limited by the diameter of the tree itself.
The tangential section is directed tangentially relative to the growth rings. This allows you to get at the output a lot of fragments of identical section shape and size.
All hardwood and softwood lumber is divided into unedged, planed or edged. In the first case, there are untreated zones on the product, which are only freed from bark and knots.
Edged materials have a saw cut parallel to each other. This is a rectangular product. Planed products from at least one surface do not have roughness. They are scruffy.
Cut type
According to the shape that the product acquires after processing, several types of lumber are distinguished. The area of application depends on their dimensions. Features of the form have both softwood sawn timber and hardwood.
The first in the presented classification is a beam. Its thickness exceeds 100 mm. This is one of the most sought after lumber. Boards, on the contrary, are limited in thickness. This characteristic does not exceed 100 mm.
The bar has a thickness of not more than 100 mm. But for this product, another parameter is important. Its width must be less than twice the thickness.
Obapol has a saw cut on one side only. The width may vary. Also recently, for decorative purposes, such a type of lumber as slab has begun to be used. This is an intermediate option between the obapole 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 lining, block house, planken and logs.
Varieties of cutting lumber
When studying what lumber is, one cannot but pay attention to the purpose of each variety. The beam can be glued, ordinary, window 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 beam.
The board is floor, deck, terraced. For each application, it is treated accordingly.
The bar can be ordinary or planed. The rest of the lumber differ in size, shape. The scope of their application may be different. They are used both indoors and outdoors.
It should also be noted that the length of sawn wood should not exceed 5 m for hardwoods, and 6.5 m for conifers. The scope in the construction business depends on their dimensions and features.
The use of softwood lumber
Coniferous wood, as a rule, is 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's cheaper
Softwood lumber is used in carpentry and construction. But most often these materials are suitable for finishing dry rooms with normal temperature conditions. For outdoor use, such wood is treated with special impregnations.
Hardwood applications
Most often, hardwood lumber has a high hardness. They are denser, heavier than coniferous varieties. 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, sheathing of walls and partitions in rooms, as well as for ceilings.
Linden, poplar or birch is not used for the manufacture of load-bearing structures or finished floors. They are soft and light.
Having become acquainted with the concept of what lumber is, what types of them are, you can navigate the purpose of products. Today there are a huge number of them.
H To move on to a more detailed discussion of lumber processing, you need to familiarize yourself with the following terminology. These are pieces of lumber.
The layer of lumber is the longitudinal wide side.
lumber edge- This is the longitudinal narrow side.
lumber rib- this is the intersection of the edge and the face.
lumber end is the end cross section.
By processing, lumber is divided into edged, unedged, one-sided edged. edged lumber called lumber with four processed sides. Wane is allowed in acceptable sizes (wane - the surface of the log).
Unedged lumber is called lumber with the side surface of the log instead of the edge. Single-sided edged lumber is called lumber with sawn faces and one edge. Wane is acceptable within the limits of GOST. Also distinguish the degree of processing of lumber. They are planed and unplaned.
In addition, depending on the location in the log, lumber can be core, central, side. According to the nature of processing, lumber is divided into unedged, edged and one-sided edged. Lumber that has a side surface of a log instead of edges is called unedged(Fig. 2a); lumber, in which all four sides are propylene, and the amount of wane (the part of the surface of the log remaining on the lumber) does not exceed the allowable dimensions, are called edged(Fig. 2b). One-sided edged lumber has sawn faces and one edge, and the dimensions of the wane on the sawn edge do not exceed the allowable. In the direction of the length of the board, a butt (wide) and apex (narrow) end are distinguished. A wane that occupies part of the width of the edge is called blunt (Fig. 2c), the entire width of the edge is sharp (Fig. 2d). 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. According to the location of the lumber in the log (in relation to their longitudinal axis), core, central and side boards are distinguished. Core lumber contains the largest number of knots and is prone to cracking. Such lumber is not of the highest grade. The central lumber cuts all annual layers and is therefore of higher quality. The side boards are sawn between the core (or central) and the slab. They have a cleaner surface, are easy to plan, and are generally characterized by better quality.