Wooden beam as an integral element of construction work

Despite the abundance of modern high-tech materials, it is still difficult to imagine any construction without the use of wood.

Among the wide range of products from a tree, the bar takes the leading positions, it is used everywhere for the most various purposes:

• Metal or wooden transverse beam - for load-bearing structures and floors;
• Conventional cylindrical and trimmed timber for building houses, building supports and large elements of stairs;
• Glued laminated timber - for the construction of more durable and expensive buildings:
• Profiled timber - for durable joining of parts among themselves, which allows to erect even and not blown by the wind walls with high thermal insulation performance;
• Wooden beam 50 to 50 (usually called a half-timber) - for mounting the lathing for interior and exterior finishing, as well as a supporting base for fences and other lightweight structures.

What is a timber, how it is made and from what, what dimensions of a wooden bar - all these and other questions will be discussed later in this article.

Raw material

Coniferous species of wood, such as spruce, pine, fir, cedar and larch, are most often used to produce timber. In smaller volumes it is produced from such hardwood as oak, birch and aspen.

For example, in the old days, aspen was considered to be the best log house for a bath, oak ceiling beams of a timber beam at all times emphasized the respectability of the owner, and birch was used for interior work. Nowadays, many also adhere to the old rules when choosing a material, because they are time tested.

In addition to traditions and preferences, it is now very important that the production process be respected and the products comply with the stated quality. All necessary information: certificate for timber, requirements for appearance, grade, size and physical and mechanical properties are set out in the standards of GOST.

Production technology

The blanks are processed on circular sawing machines by longitudinal trimming from a log from two to four sides, in order to give it the necessary shape and size, followed by drying. Glued laminated timber passes a more difficult way, but the output is the most durable of all types (50-70% better than usual).

Main steps:

• Cutting logs on individual boards;
• Drying to a moisture content of 10-15% in special chambers;
• Treatment of boards with an antiseptic agent, and anti-corrosion impregnation (for a longer service life);
• Calibration according to size;
• The connection of the workpieces, the orientation of the elements in the direction of the fibers, so that the finished timber later would not “twist” or “lead”;
• The resulting blanks are glued under the press with a special adhesive for wood;
• Profiling is the final step that sets the parameters.

If necessary, with the help of bending in industrial conditions, the shape is given to the products necessary for specific purposes.

Bending wood

How to bend the wood? First of all, bending is associated with deformation of the inner and outer layers of the material. Internal - are compressed, external - are stretched.

The technological process of production includes such steps as:

• Hydrothermal treatment (to improve the plastic properties);
• Bending;
• Drying after bending (to fix the form).

Hydrothermal treatment - steaming in boilers with saturated steam under low pressure.

Classification bars

If the boards are divided into edged and not edged, then the degree of filing of the bars is measured by edges.

• Dvuhkantny timber. The two sides remain in the form of log rounded. Two opposite sides are processed;
• Three-edged cant. Only three surfaces are longitudinally processed, the latter remains in the initial state;
• Four cant beam. Processed from all four sides, as we used to see it.

According to the surface relief:

• Not profiled (simple), with smooth edges and faces;
• Profiled The two opposite sides are perfectly smooth (achieved by grinding, planing or milling). The remaining two have special grooves (grooves and ridges).

Profile bars increases the contact area of ​​structural elements and increases strength. Also, the house of profiled parts needs to be insulated less, it takes less time to install, it has excellent thermal insulation and sound insulation.

Dimensions

The range of a wooden bar is rather wide. Basically the length is 6 meters, but the range is from 2 to 8 meters. Glulam is again ahead of everyone, because Because of the production technology, it can be made of almost any length (if it makes sense), but the maximum effective length is 18 m.

Dimensions (стандартные):

• Thickness: 100 mm, 125 mm, 150 mm, 175 mm, 200 mm, 250 mm;
• Width is from 100 mm to 275 mm.

The manufacturer can produce products of other sizes, for example, 188? 140, 195? 145, 400? 400, etc.

The most popular is a square section of 150 by 150 for several reasons:

• To build a wall, for example, a height of 1.2 meters, 12 elements of 100 mm are needed, and if you take parts of 150 mm, you will need only eight of them. The number of rims is also reduced (exactly 1.5 times), which means that the cost of insulation, labor costs and installation time are reduced;
• The thickness of the walls of 150 mm worse skips sounds.

Tip: The thickness and height of 150 mm are optimal because 100 mm is not enough for walls, and 200 mm is a lot. Two hundred millimeter beams increase the overall load on the foundation, complicate the installation process with your own hands, which means that the budget will suffer.

Bars are assigned dirt, depending on the quality of surfaces and humidity.

By humidity, wooden beams are classified into:

• Normal (natural humidity) 82-87%;
• Dry, 10-15%.

The bar of natural moisture easily turns into dry; this is achieved by drying in special drying chambers. Accordingly, the cost increases, but the quality is worth it. In the dry state, the usual material is closer to the glued.

Shrinkage «мокрого» материала очень продолжительна (12-18 месяцев), и в это период нельзя производить внутреннюю отделку и устанавливать внутренние перекрытия. Shrinkage «сухого» позволяет отделывать помещения практически сразу.

Specifications

Compressive strength along fibers

The average strength of all wood species is 450 kg / cm ?. This indicator depends on the type of wood, type of load, duration of exposure, cross-sectional area, conditions of use.

Volume weight (kg / m?)

The indicator depends on humidity, age and wood type.

Density of individual rocks (in dry condition):

• El - 445;
• Pine - 500;
• Пихта - 375;
• Oak - 700.

For freshly chopped:

• Soft deciduous and coniferous - 850 kg / m ?;
• Solid hardwood - 1000 kg / m? \

Heat conductivity (W / (m · ° С))

For pine - 0.09-0.18; For oak - 0.10-0.23. Thermal conductivity properties increase due to the increase in thickness and decrease in humidity, and decrease at high humidity and small thickness.

Diseases

Increased humidity, contact with infected trees, poor temperature conditions, lack of air - all this can lead to fungal diseases, rot, mold and bio-damage. In order to avoid these problems, you need to impregnate the tree with special solutions.

Violation of the form

When temperature or humidity drops, the tree can change its shape (curl, crack). Dry material is less susceptible to change, but overdrying is also a problem. Also, defects may appear, which were laid at the time of the growth of the tree itself, or due to improper construction, or improper manufacture.

Shrinkage

• Normal - 40-80 mm \ m;
• Normal profiled - 15-20 mm \ m;
• Glued - 5-10 mm \ m.

Fire resistance

The time to ignition of a wall 15 cm thick (plastered on both sides) is 45 minutes. To protect against burning cause flame retardants.

Water absorption

Dry timber can absorb up to 30% per day. The water absorption coefficient depends on the degree of saturation of the wood with water, the more water there is, the less it will be able to absorb.

Advantages of timber

• Strength, elasticity;
• Low mass;
• Outstanding thermal insulation qualities. A house built of wood retains heat 6 times better than a brick house, and 1.5 times better than foam concrete;
• Comfortable microclimate. The house "breathes", which always provides a comfortable temperature and humidity;
• Balk is less susceptible to violations of geometry than a regular log;
• The price of timber is lower than the rounded logs;
• The walls of the profiled and glued parts do not need to finish, the walls are smooth and pleasant texture;
• Short installation time;
• Aesthetics.

disadvantages

• What would the walls of the non-profiled timber kept warm well and did not draw water? You should do the exterior finish. Otherwise, water will force air bubbles out of the tree and then the material will lose its insulating properties;
• Exposure of solid timber to cracking. Glued these problems does not suffer;
• Structures of laminated wood can not be operated at a temperature of more than 35 degrees, and non-glued - 50 degrees.

Transportation

Bars are usually transported in block-packs, or construction packs, as well as simply stacked exactly.

Storage

Tip! The instruction on how to store the material is quite simple: the bar should be stored in proper conditions, at a certain temperature, on a flat surface, not under the sun (if it does not require drying). It is also impossible to store products in wet places.

Conclusion

There are many types of building materials, and timber compared to the rest occupies one of the leading positions. Like any material, it has its advantages and disadvantages.

Additional information on this topic can be found in the video in this article.