Wood. Lumber and wood products. What is lumber and its varieties for construction and domestic use
The unique properties of wood - strength, long service life, environmental friendliness, pleasant aesthetic appearance, have made it a popular building material, raw material for furniture production, decorative coating, folk art. People working with wooden blanks after sawing them are called upon to be well versed in the types of lumber, to know their technical characteristics.
Variety of raw materials and its preparation for cutting
When classifying wood according to the degree of preparation, the moisture content of the material is taken into account. Absolute humidity is determined by the ratio of mass - moisture and dry wood per unit volume.
There are several types of lumber
External lumber with an air dry or natural humidity more than 18–20% obtained after prolonged exposure to air. It is used in construction and for the construction of wooden structures.
Universal lumber with a moisture content of up to 15%, it is used for arranging skirting boards, platbands, timber.
– in a special box at high temperature. Humidity - within 8-10%. Absolutely dry wood is treated with a protective composition to protect it from absorbing moisture from the atmosphere.
Insufficiently dried or improperly stored wood is subject to warping, rotting or decay. To prevent this from happening, lumber needs additional processing in steam chambers.
All wood is divided into several types:
- edged material, when the workpiece is processed from all sides;
- unedged pieces - processing only on one side.
Processing method:
- unmilled lumber;
- milled or planed.
There are ways of cutting in relation to the growth rings of wood:
- The radial cut is oriented towards the center of the rings. Blanks - with different sizes, widths, limited cross section logs.
- Tangential - the cut is directed to these rings tangentially and contributes to the production of long boards with the same dimensions and sectional shape.
Each type of lumber cutting serves to create various forms products. It is the variety of sizes and shapes that allows the use of processed wood in all spheres of human activity.
Classification of processed lumber
There are several types of lumber, depending on the degree of processing.
plate- half a log obtained by sawing a tree in the center. It is used for the manufacture of sleepers, timber, massive boards.
bar- a common result of woodworking. Used in the arrangement of cladding and in the form self-design in buildings. The beam has a thickness not exceeding 100 mm, and a width less than twice the thickness.
Depending on the number of processed sides, there are two-, three- and four-edged timber. There are varieties of it:
- simple beam;
- rounded beam.
Influence of part size on its classification
Bar- the same beam, but with smaller dimensions, standard size section 40×40 or 50×50 mm. It is used in the furniture industry and for the production of joinery.
Rail- a type of bar, flatter and narrower, found in different sizes. Often such a product is sawn directly at the construction site, its width and height are adjusted to the required dimensions.
Board- edged products, in which the width ranges from 85 to 140 mm, and the thickness ranges from 27 to 45 mm. Products are needed in capital construction, for interior decoration, in the manufacture of furniture.
The board is divided into 5 grades:
- Selective - applicable in shipbuilding, car side battening and creating elite-class interiors.
- Timber of the first and second grade is suitable for the production of furniture facades.
- Application of a third-rate board - construction objects.
- For boards of the fourth grade - the production of boxes. With their help, large mechanisms are packed for shipment.
Popular types of boards:
- Parquet - its lower layer is made from roughly processed wood, and for the top, rocks from among the elite are taken.
- - strong and light, it is made from the best wood.
- Window sill - well dried, with special impregnation.
- Engineering - with a top made of wood and a bottom layer of plywood.
Additional classification of materials by purpose
Clapboard - lumber used for interior and exterior cladding. In the technical documentation, it is called a cladding board. Street sheathing is carried out exclusively with solid lumber.
The sleepers are made from precious wood, with an excellent condition of the tree, as they are subject to the adverse effects of the external environment and heavy loads from heavy trains.
They select lumber that can securely hold the rails and dampen the vibration of trains. Railroad sleepers are often made from pine, and are sometimes made from spruce, fir, red maple, and Siberian cedar. To prevent rotting and rapid destruction, they are impregnated with a special substance.
Small moldings - these products include corners, skirting boards, platbands, glazing beads - of various sizes to satisfy the need for the selection of the best options.
Slab - a waste of sawing a log into boards, its lateral part. It is used for the construction of temporary buildings, as a crate under the roof. Some designers advise customers to do decorative trim with this lumber. The low cost of such wood made the slab in demand.
Obapol (quarter) is an unfinished version of the board, it has only one side that is flat, the width along the entire length is not the same, so the longitudinal cut has an irregular shape.
A wide range of wood and an abundance of lumber, differing in - real opportunity pick up all the details of the interior with profit.
Tree species for lumber
Known types of lumber from various tree species, they can refer to two types of wood:
- coniferous;
- deciduous.
Almost all hardwood lumber with an aesthetic appearance and operational properties suitable for interior decoration.
Both coniferous and hardwood species of different price groups are environmentally friendly materials. They are now popular for interior decoration and exterior work in the construction of private houses.
But it is necessary to choose the right wood and take into account performance various kinds lumber.
Features of coniferous materials
Larch- resistant to water, not damaged by insects and fungi, decay rarely occurs.
Pine- less durable, more prone to fire than other types of wood, due to the resins protruding on its surface.
Cedar- close in quality to pine and has a pronounced and rich texture of wood, resistant to decay and is able to disinfect the air in rooms where there are products from it. Lumber is rarely used because of the high price.
Yew- wood of red-brown color with veins, is durable and hard, has many knots. The material is not subject to a wormhole, insensitive to precipitation. Yew bars are good for carving, and veneer is good for mosaic work.
Fir- light and not too elastic wood, convenient in woodworking. It is produced from roofing materials, lining for a covering of buildings. The absence of the characteristic smell of gum allows the use of the material for the manufacture of food packaging (barrels and boxes).
Hardwood range of materials
Acacia- solid wood yellow color with pronounced growth rings. It does not crack or warp, it has elasticity, high friction resistance, and can be perfectly polished. Parts of woodworking tools and carpentry workbenches are made from it, and veneer is good for mosaic work.
Oak- demanded wood in the construction of houses and structures. It has beautiful texture, high strength, rot resistance, bendability and durability. Oak blanks are used for the production of furniture and parquet, arts and crafts.
Ash- with mechanical properties close to oak. High bending ability and strength are the advantages of wood. But it is easily damaged by a wormhole, and needs antiseptic treatment. Ash lumber is used for the manufacture of furniture and gymnastic walls.
Aspen- from hardwood lumber, it is easy to process, used for, in various works. Most often, its wood is spent on; plywood or chipboard is made from it.
Alder- soft wood does not rot, it is used for the manufacture of furniture, the construction of houses, pantries and log cabins of wells, the material does not smell and does not absorb third-party odors.
Birch is a durable wood with a beautiful texture, easy to work with, but resistant to decay. It is used for the manufacture of plywood, chipboard and peeled veneer used in the manufacture of furniture.
The hornbeam or white beech belongs to a tree species with strong and hard wood. After drying, this figure increases, exceeding the quality of oak. Difficult to handle cutting tools but it does well.
Maple - with a solid light yellow wood that can be processed and polished, does not warp, and is easy to cut. Wood is in demand for arts and crafts, especially successful are carvings from her.
Video: Types of lumber
>>Technology: Lumber and wood-based materials
When sawing tree trunks longitudinally at sawmills, they get various lumber(Fig. 11): bars, bars, boards, plates, quarters and slabs.
bar- lumber with a thickness and width of more than 100 mm. If the beam is sawn from two sides, then it is called two-edged, and if from four sides, then four-edged.
bars- sawn timber with a thickness of less than 100 mm and a width of less than twice the thickness.
Boards- sawn timber with a thickness of up to 100 mm and a width of more than double thickness.
plates obtained by longitudinal sawing of a log in half, and quarters - into four parts.
croaker, or obopolom, called the sawn side of the log.
Lumber has the following elements: face, edges, ribs and ends.
plastic called the wide plane of the lumber, and the edge - the narrow plane.
edge is the line of intersection of these two planes.
Butt- transverse (end) plane of lumber.
Plywood is widely used as a structural material. Plywood is obtained by gluing three (or more) thin sheets of wood - veneer onto each other. "Veneer" in translation from German - "sliver" (shavings). The veneer is cut (peeled) with a sharp knife of a special peeling machine while rotating a log about 2.0 m long (Fig. 12). In this case, the log, like a roll, is rolled into a veneer tape.
The veneer tape is cut into square sheets, which are dried in dryers, smeared with glue and stacked on top of each other so that the direction of the fibers in them is perpendicular to each other (Fig. 13). Sheets are glued together under pressure. So get plywood with a thickness of 2 to 20 mm. 
Plywood is stronger than wood, almost does not dry out and does not crack, bends well and is processed. Plywood is used in construction, furniture manufacturing, mechanical engineering and aircraft construction.
Peeled veneer is used to make curved wood, which is used to make furniture, sports equipment and other products.
Chipboards (chipboards) are obtained by pressing and gluing chopped wood in the form of shavings, sawdust, wood dust. For the production of particle boards, they are mainly used wood waste and even bark.
Plates are made with a thickness of about 10 ... 26 mm. They are durable, almost do not warp, are well processed by cutting tools. Furniture, doors, partitions, walls, saws are made from them. However, over time, they release substances harmful to health, so they are undesirable for use in residential areas.
Fibreboards (MDF) are pressed in the form of sheets from steamed and crushed to individual fibers of wood pulp. They have a pleasant grey colour, smooth surfaces, dull, like plywood. They are used for interior decoration of premises: facing walls, ceilings, floors, in production
furniture, doors.
The disadvantage of plywood, chipboard and fiberboard is that they are afraid of moisture. Under the action of water and moisture, plywood delaminates, and the boards swell, lose strength and crumble.
PRACTICAL WORK
Examination of samples of lumber and wood-based materials
1. Consider samples of lumber and determine their type (bars, boards, slabs, etc.). Determine the types of wood.
2. Find the face, edge, edge, butt in the lumber samples.
3. Consider samples of plywood, chipboard and fiberboard, measure their thickness. Count the number of layers in the plywood samples.
4.Check whether the samples are easily processed with any tool (file, hacksaw, etc.).
- Lumber (beam, board, bar, slab), lumber elements (face, edge, edge, butt), veneer, wood-based materials (plywood, chipboard and fiberboard).
1. What types of lumber do you know?
2. Name the main elements of lumber.
3. What is veneer?
4. What is plywood made of and how? Chipboard? Fiberboard?
5. How are wood-based materials different from wood?
6. What are their advantages, disadvantages?
A.T. Tishchenko, P.S. Samorodsky, V.D. Simonenko, N.P. Shchipitsyn, Technology Grade 5
Submitted by readers from the website
Sections: Technology
Goals: to acquaint students with wood as a structural material, with types of lumber.
Tasks:
- educational: to teach to determine the appearance of samples of wood species.
- educational: cultivate a respect for wood and wood.
Means of education:
- Presentation for the lesson.
- Collection of samples of tree species.
- A set of wood lumber.
- Samples of veneer, plywood, chipboard, fiberboard.
Lesson progress
I. Organizational moment
Check readiness for the lesson.
II. Lesson topic message
Wood is a natural structural material. Lumber.
III. Motivation for learning activities
Wood is one of the most important and widespread material. The ease of processing and the variety of species made it possible to use wood for the most various works. Each wood product has its own requirements. To correctly determine which wood to use for a product, you need to know the characteristics of each species.
IV. Formation of knowledge and skills
History reference.(slide number 1)
It is difficult to name an area of human activity where wood was not involved. Already on early stages development man began to use this material. A little later, wood began to be used for construction (houses, bridges, ships), various household equipment, furniture, dishes, musical instruments and much more. With the advent of crafts, wood became one of the first structural materials for the manufacture of spinning, weaving, milling, pottery and other machines. It was widely used in the car, ship, auto and aircraft industries. Currently, products of thousands of names and purposes are manufactured.
wood structure(slide number 2)
The structure of wood can be seen in its cross section, which clearly shows pith, bark and annual layers. For a more complete picture of the structure of wood, you need to consider three main sections of the trunk - transverse, radial and tangential. On the transverse section, the annual layers look like concentric circles, on the radial - longitudinal stripes, on the tangential - winding cone-shaped lines. In addition, on the transverse section, you can see light lines directed from the core to the cortex, core rays. The dark-colored part of the trunk is called the core, and the light peripheral part is called sapwood.
Wood species(slide number 3)
Coniferous breeds. Coniferous wood has a lower density, and therefore, it is easier to process and its heat-saving properties are higher.
The group of conifers includes the following species:
- Pine - the most common coniferous tree. The color of its wood can be brown, reddish, yellowish and almost white with slight stains of red. When dry, pine is light and pliable for joinery work. Furniture, windows, doors, etc. are made from it. Wood is well processed by dyes and varnishes.
- Spruce - softer than pine, but it has a large number of small and medium knots, which makes it difficult to use in responsible carpentry structures. The texture is inexpressive, it is less moisture resistant, more likely to rot. In carpentry, it is used for non-responsible furniture designs.
- Fir - It is used on a par with spruce, although it has reduced physical and mechanical properties.
- Larch - occupies a special place among other conifers. Its wood has a red-brown, sometimes brown tint and is highly durable (stronger than oak) and moisture resistant. It is used in building structures where high strength and resistance to decay are required, it is used for the manufacture of parquet.
- Cedar - has a whitish-yellow wood with different color shades depending on the place of growth. Wood does not differ in high strength and density. Cedar good stuff for carving. It is trimmed mainly with wax.
- Juniper - coniferous shrub, trunk diameter is up to 10-15 centimeters. Strong thin-layer wood is well processed and polished, has a specific smell. It is used for the manufacture of small parts, when turning, for carving and mosaic work.
- Cypress and thuja similar in properties to juniper, but their wood is broader and darker in tone. Used for small carvings.
Hardwoods:
- Oak - It is characterized by high strength, hardness, resistance to decay, bending ability, beautiful texture and color. Wood is widely used for the manufacture of furniture, parquet. Oak veneer is used for facing plywood, chipboard.
- Beech - has a strong and solid wood, it is not inferior in strength to oak. Beautiful texture on cuts, these decorative qualities are used when facing furniture with sliced veneer.
- Birch - It is characterized by high strength, uniform structure and color, medium density and hardness. It is mainly used for the manufacture of plywood, peeled chipboard veneer. Easily processed and finished, when etched under more valuable breeds. In the steamed state, it bends well.
- Disadvantages - dries for a long time, easily pricks, cracks and warps a lot. Wood Karelian birch viscous and hard, easily amenable to carpentry. It is highly valued in mosaic work and as an ornamental material.
- Ash - wood similar to oak. It bends well after steaming.
Wood defects(slide number 4)
Curl - it is an undulating arrangement of fibers, especially at the root of the tree. Most often observed in maple, oak, Karelian birch, walnut. Such wood is difficult to process, but is valued in the manufacture of sliced veneer.
Curl characteristic of local curvature of the annual layers due to the influence of progrowth or trunk knots.
- Sprout - a defect in the area of \u200b\u200bthe tree that arose as a result of mechanical damage to the fiber. Such a defect most often occurs due to the growth of dead wood or bark into the sapwood.
- Oblique - a defect expressed in the fact that the wood fibers are placed obliquely. Slanted wood is not used for crafting.
Wood color (slide number 5)
The color of wood is one of the signs by which one type of wood differs from another.
Wood linden, pine, birch, maple, aspen- light, oak and ash- brown, walnut, teak - brownish.
Color shades of different species can be classified into main groups, where one color of wood will prevail.
- Yellow - birch, spruce, linden, aspen, hornbeam, maple, fir, ash, barberry, Karelian birch.
- Brown - cedar, poplar, beech, larch, alder, pear, plum, chestnut.
- Brown - cherry, apple, apricot, walnut.
- Red - yew, mahogany.
- Pink - laurel cherry, plane tree.
- Orange - buckthorn.
- Violet - lilac, privet.
- Black - bog oak, ebony.
- Greenish - persimmon, pistachio.
Physical and mechanical properties of wood(slide number 6)
- Hardness - ability to resist machining with cutting tools. The bottom of the barrel is harder than the top.
- Strength - the ability of wood to resist forces acting on it.
- Elasticity - the ability of wood to change its shape under the influence of external forces and to take its former shape after the termination of this influence.
- Plasticity - the ability of wood to change (without destruction) its shape under pressure and retain it after the load is removed.
Conditional density wood is the ratio of the minimum mass to the maximum volume of the sample. By density at a moisture content of 12%, tree species are divided into groups:
- low density
- medium density
- high density
Humidity - physical property of wood, characterized by the amount of moisture contained in it.
Hygroscopicity - is the ability of wood to absorb or release moisture.
Thermal conductivity - the ability of wood to conduct heat from one surface to the opposite. Conifers have a lower density and, consequently, lower thermal conductivity.
Sound conductivity - the ability of wood to conduct sound. Sound travels in different directions with different force. So, the sound conductivity along the fibers is 4-5 times higher than across.
High flammability wood reduces the fire resistance of the building.
lumber(slide number 7)
- bars- these are sawn timber with a thickness and width of more than 100 mm (up to 400x400 mm). According to the number of sawn sides, the bars can be two-edged, three-edged and four-edged.
- Boards- these are lumber with a thickness and width from 16 to 100 mm., The width of which exceeds the thickness by at least 2 times. By the nature of processing, they are unedged, single-edged and edged. The width of the boards is from 275 mm, the length is up to 6.5 m. The wide side in the boards is called the face, and the narrow side is called the edge.
- bars- these are lumber with a thickness of 50 to 100 mm, and a width of no more than double the thickness.
- Sliced and peeled veneer serves as material for facing and mosaic works. Obtained by planing or peeling wood:
- shelled- birch, alder, spruce, pine, beech-linden.
- planed- walnut, ash, beech.
- Plywood consists of several (three, five or more) glued layers of peeled veneer.
- Practical work.
To acquaint students with the appearance of the most common types of wood, samples of lumber, veneer, plywood. To teach students to determine the type of wood and the type of lumber by the appearance of the samples.
V. Summing up the lessons
Today you got acquainted with wood as a structural material. We learned about the structure of wood, remembered various species. Familiarized with various properties wood. We knew what lumber is and where they are used. This knowledge will be useful to you in the further study of wood processing technology, and some may be useful in everyday life.
ADVICE. If possible, these slides can be printed as posters or as student handouts.
If you want to purchase material from exotic tree species with an original natural pattern, you will have to overpay in comparison with lumber from ordinary trees. Strength also has great importance when choosing wood. Distinguish between hard rock, which is used in the construction of building frames or the installation of load-bearing elements. Lumber with medium strength is often used in the manufacture of furniture. With the help of soft rocks, one can try to reduce the cost of the structure by using them in the production of non-load-bearing building elements. Durable species include cherry, hornbeam, maple, ash, oak, beech. For the production of furniture, alder, linden and coniferous trees are used. Poplar and birch are soft woods.
To date, lumber manufacturers offer processed and freshly cut products from the highest to the third grade. The highest is the most valuable. Materials are available in different sizes. The edged board, made according to new technologies on high-quality equipment from environmentally friendly raw materials, is popular. When choosing lumber, you should pay attention to their quality and then the manufactured products will delight you and your family.
| Read also |
|---|
Grape
In gardens and home gardens, you can choose a warmer place for planting grapes, for example, on the sunny side of the house, garden pavilion, veranda. It is recommended to plant grapes along the border of the site. The vines formed in one line will not take up much space and at the same time will be well lit from all sides. Near buildings, grapes should be placed so that water flowing from the roofs does not fall on it. On level ground it is necessary to make ridges with good stock through waterways. Some gardeners, following the experience of their colleagues in the western regions of the country, dig deep planting holes and fill them with organic fertilizers and fertilized soil. Pits dug in waterproof clay are a kind of closed vessel that fills with water during the monsoon rains. In fertile land, the root system of grapes develops well at first, but as soon as waterlogging begins, it suffocates. Deep pits can play a positive role in soils where good natural drainage is provided, the subsoil is permeable, or reclamation artificial drainage is possible. planting grapes
You can quickly restore an obsolete grape bush by layering (“katavlak”). To this end, healthy vines of a neighboring bush are placed in grooves dug to the place where the dead bush used to grow, and sprinkled with earth. The top is brought to the surface, from which a new bush then grows. Lignified vines are laid on layering in spring, and green ones in July. They are not separated from the mother bush for two to three years. A frozen or very old bush can be restored by short pruning to healthy above-ground parts or pruning to the “black head” of an underground trunk. In the latter case, the underground trunk is freed from the ground and completely cut down. Not far from the surface, new shoots grow from dormant buds, due to which a new bush is formed. Grape bushes that have been neglected and severely damaged by frost are restored due to stronger fatty shoots formed in the lower part of the old wood and the removal of weakened sleeves. But before removing the sleeve, they form a replacement for it. Grape care
A gardener starting to grow grapes needs to study well the structure of the vine and the biology of this most interesting plant. Grapes belong to liana (climbing) plants, it needs support. But it can creep along the ground and take root, as is observed in Amur grapes in a wild state. The roots and the aerial part of the stem grow rapidly, branch strongly and reach large sizes. Under natural conditions, without human intervention, a branched grape bush grows with many vines of various orders, which comes into fruiting late and yields irregularly. In culture, the grapes are formed, give the bushes a form that is convenient for care, providing a high yield of high-quality clusters. Vine
Lemongrass
In the literature on climbing vines, the methods of preparing planting pits and the planting itself are unnecessarily complicated. It is proposed to dig trenches and pits up to 80 cm deep, lay drainage from broken bricks, shards, install a pipe to the drainage for food, cover it with special earth, etc. When planting several bushes in collective gardens, such preparation is still possible; but the recommended depth of the pit is not suitable for the Far East, where the thickness of the root-inhabited layer reaches 30 cm at best and it is underlain most often by impervious subsoil. Whatever drainage is laid, but a deep hole will inevitably turn out to be a closed vessel, where water will accumulate during the monsoon rains, and this will entail damping and rotting of the roots from lack of air. Yes, and the roots of actinidia and lemongrass vines, as already noted, are distributed in the taiga in the surface layer of the soil. Planting lemongrass
Chinese lemongrass, or schizandra, has several names - lemon tree, red grape, gomisha (Japanese), cochinta, kojianta (Nanai), kolchita (Ulchi), usimtya (Udege), uchampu (Oroch). In terms of structure, systemic relationship, center of origin and distribution, Schisandra chinensis has nothing to do with the real citrus plant lemon, but all its organs (roots, shoots, leaves, flowers, berries) exude the aroma of lemon, hence the name Schisandra. A clinging or winding liana of lemongrass, along with Amur grapes, three types of actinidia are original plant Far Eastern taiga. Its fruits, like a real lemon, are too acidic for fresh consumption, but they have medicinal properties, pleasant aroma, and this attracted a lot of attention to it. The taste of Schisandra chinensis berries improves somewhat after frost. Local hunters who consume such fruits claim that they relieve fatigue, invigorate the body and improve eyesight. In the consolidated Chinese pharmacopoeia, compiled back in 1596, it says: "Chinese lemongrass fruit has five tastes, classified in the first category of medicinal substances. The pulp of lemongrass is sour and sweet, the seeds are bitter-astringent, and in general the taste of the fruit is salty. Thus, It contains all five tastes. Grow lemongrass
Types of wood and characteristics of lumber in photographs.
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.
Table of lumber characteristics.
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:
Timber classification and characteristics:
Scheme of lumber types.
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
Timber classification scheme.
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. The smell and color of pine add to the attractiveness of 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. .
Scheme of options for sawing wood.
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 for construction works edged and unedged boards, they differ in a number of ways. These lumber are very popular, they are used for the construction of house frames, for the installation of strips, walls, partitions, for installation 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.
Calculation table edged board.
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 perform 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:
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.
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 it is important appearance materials.
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.
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 used for construction and repair work various types, are 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.
Overview Types of wood and lumber characteristics.
None of the building materials on the market today has such unique qualities as natural wood.
It is very convenient and easy to handle, so that you can do anything, even a spoon, even the fuselage of an aircraft. Wood has excellent strength, it is light and has a pleasant smell. Working with wood brings real pleasure, if you understand what types of wood and the characteristics of lumber are.
Building materials from wood
If you look closely at any wood bar, you can see on it a texture pattern formed by growth rings. Its appearance depends on the direction in which the tree trunk was sawn. It is customary to cut it in three directions: along and across the fibers, as well as at an angle of 45 degrees. If the cut is made at an angle, then it is called tangential.
It forms a texture similar to cone-shaped lines.Three different types cuts depending on the direction If the cut is made along the fibers, then it is called radial. Parallel lines formed by the fibers are clearly visible on it. A cross section in all its glory shows us the growth rings of a tree trunk. Figure has importance for the external beauty of wood products, therefore, before making a wooden blank, you must clearly understand yourself in which direction we want to have patterns.
The internal structure of wood
In order to understand the structure of a tree trunk, it is necessary to make a complete cross section.
The top layer is called the bark. It is of no interest, so it is removed. The next thin layer is the so-called growth zone.
It is difficult to see, but if the tree is young, then after removing the bark, you can see green fibers that are moist to the touch. They are also called cambium. After it, the wood itself begins with pronounced growth rings.
Professionals call it sapwood. In the center of the trunk is a darker or merging with sapwood heartwood. It depends on the type of wood, which can be sapwood or heartwood.
Heartwood species are represented by all conifers (cedar, pine, spruce, larch, yew) and some common deciduous species such as oak, poplar, ash. The vast majority of deciduous trees are sapwood: birch, alder, hornbeam, maple.
The density of wood cells affects the strength and other physical qualities of wood, but the pattern of growth rings and heart-shaped vessels affects the creation of artistic compositions and the possibility of using one or another raw material in work. These are macrostructural elements, and they can also include knots, growths, undeveloped shoots that deviate annual rings and form various twists.
Wood with a pronounced macrostructure is most interesting for processing, therefore, without exception, all conifers are used for crafts.
Physical characteristics of wood
Like any building material, wood has a number of physical properties:
Density is measured in g / cm3 and depends on the type of wood and its moisture content. The higher this indicator, the stronger and heavier the material, it is more durable and less prone to decay.
The most dense wood is considered to be oak, ash, maple and larch, and aspen, spruce and fir have the lowest density. The moisture content of wood indicates the degree of its quality and durability. Room dry has 8 - 12% moisture, air dry from 12 to 18%, and atmospheric dry 18 - 23%. If the humidity is even greater, then such wood is called raw. Sound and thermal conductivity are important qualities.
High-quality dry wood perfectly retains heat and sound in the transverse direction. Thermal conductivity is reduced along the fibers, but the sound propagates along the barrel perfectly. This is even an indicator of quality and dryness. Corrosion resistance, which is higher in softwood, due to the presence of resin in it. Texture, color, smell and gloss make it possible to determine the type of wood and determine its decorative value.
All of the above physical properties very important for the use of a particular tree species.
Mechanical characteristics of wood
The mechanical properties of different types of wood are more important. After all, they affect the strength and durability of buildings or wood products. Mechanical strength is the ability to resist various static and dynamic influences from outside.
The strength of a material depends on the direction of the load. In this regard, it is customary to distinguish between shear or shear strength, bending and compression. Any wood has greater strength along the fibers than across them.
Strength test of a wooden bar in the direction of load
It is worth noting that wet wood becomes less durable. The same is observed in light and loose breeds.
Plasticity is the property that allows you to create bent parts from wood. More plastic breeds keep the form received at certain long influence.
Humidity and temperature increase this indicator very much, so for the manufacture of curved parts, wood is exposed to hot water or a couple. Beech, elm, oak, ash can boast of high plasticity. This cannot be said about conifers, since the structure of their fibers is too straightforward.
The hardness of wood is the ability to resist the various penetration of foreign bodies into it. There are hard woods such as beech, maple, larch, oak, ash, elm (the hardest are boxwood and acacia) and soft woods such as linden, alder, spruce, pine. The level of wear resistance of wood directly depends on its hardness.
Characteristics of various types of wood
For various purposes, one or another type of wood is used.
All of them are divided into coniferous and deciduous. The former have a sharp resinous odor and a pronounced macrostructure. The most common conifers are: cedar, pine, fir, spruce and larch.
Pine is the most common building material. Its color varies from pale yellow to reddish yellow. The wood is quite light and strong.
The main thing is that it is very convenient for processing. It contains a lot of resin, so it rots poorly and is not particularly afraid of precipitation. Due to its softness, it easily accepts various dyes and varnishes.
Warping during drying almost does not occur in pine. The disadvantage is the impossibility of high-quality finishing and coloring. However, it is successfully used for the production of furniture and plywood. Spruce can be put in second place after pine in terms of use.
There is not much resin in it, so it is more susceptible to decay and precipitation. Spruce wood is strong and light, but at the same time it has a large number of knots, which significantly reduces its consumer qualities. The advantages include White color wood and low resin content.
It holds various fasteners well. In construction, not the most important details are made from it. Cedar, or correctly Siberian pine, is in no way inferior to spruce in its building qualities, and far surpasses it in resistance to decay. Despite the softness of cedar wood, it has a good density and strength, while being perfectly processed. Fir is no different from spruce: it easily lends itself to any processing and does not perceive caustic chemicals.
It does not contain enough resin, which is why the wood rots too quickly without the use of special treatment. Larch is valued for its hardness and strength. Its density is such that the trunk of this tree sinks in water. But larch wood practically does not rot.
Hardwoods are usually divided into soft and hard.
Their wood is odorless. It is only available fresh. Hardwood species include oak, ash and birch, and softwood aspen and alder.
Oak has very high strength and resistance to decay. Its wood has a beautiful color and texture. It does not crack or warp, which is why furniture, luxury items and art are made from oak.
Tannins have powerful antiseptic properties. The strongest and most beautiful oak wood is obtained when it is kept for 1.5 years in a flowing cold water. Its color becomes black.
Expensive furniture items are made from such stained wood. It is an ideal material for the production of furniture, but it is very inconvenient to process due to its density and strength. Birch wood has an average density and hardness. It is strong and quite viscous, has a not very pronounced texture, but is homogeneous.
The disadvantages of this material are susceptibility to severe cracking and warping, too much shrinkage, little resistance to decay, and a fairly frequent lesion with such an ailment as a wormhole. However, it works well hand tool, sticks together in plywood, is easily polished and stained, makes it possible to produce very fine embossed carvings. Aspen has a rather soft wood, in which there are so few knots that it lends itself well to any processing. However, its porous structure does not allow making small details. Linden is highly valued in the manufacture of various carved parts for furniture production.
It does not warp and does not crack at all during shrinkage. Linden wood has a fairly strong structure, which is very little susceptible to decay. Maple has a strong, dense and slightly drying wood. It almost does not warp, but quickly rots and is highly susceptible to wormholes.
This wood is well processed, glued, trimmed and painted. It is used in carvings and in the manufacture of solid wood parts. Mahogany, which grows in evergreen tropical forests, has red wood. It is not just one species, but a multitude with similar properties.
Mahogany wood is very soft and perfectly workable, easy to polish, and also absorbs varnish. Some pieces of furniture are made from such wood. Its high cost does not allow making the entire product out of it.
Rare wood species
Rare wood species
Lumber and its varieties
Mostly at the timber base and in the store they sell dry wood. Raw is rarely sold. If you decide to build something or make a piece of furniture, then you will come across the names of types of lumber, the meaning of which is worth understanding:
- The ridge is essentially solid tree trunks without bark or their pieces of a sufficiently large length. It is important that their diameter exceeds 25 cm. The garter is the same ridge, but less than 25 cm in diameter. The pole is a solid trunk without bark with a diameter of less than 9 cm. The plate is half of the ridge, which is sawn along the fibers. fibers. Lezhen, or in another way a beam with a wane, is a log hewn on both sides that can be placed on one of two planes. I call a beam a log that is hewn on four sides with a cross section of at least 100x100 mm. If it is smaller, then the product is called a bar. The board can be very different depending on the method of its processing and size: unedged, edged, slab, planed on four sides, grooved, folded.
Cross sections of boards depending on processing.
All lumber that is commonly used in construction has its own specific names. They differ in the thickness of the product, as well as the ratio of width to this thickness.
For boards, this ratio should never be more than 2. The maximum allowable board thickness is 100 mm. The length of any material from hardwood does not exceed 5 m, and from coniferous 6.5 m.
The main types of lumber
After reading this article, you have become familiar with the basic concepts and characteristics of wood. Therefore, with such knowledge, you can safely purchase lumber, in terms of terms, no worse than sellers. Today, almost no major construction or renovation can do without the use of wood to one degree or another, so such knowledge will be very useful.