All about LVL

LVL is a building material produced by gluing thin peeled veneer. It appeared on the domestic market not so long ago - from mid-2009. Lumber with a multilayer structure is widely used in the construction industry. Consider its pros and cons, manufacturing technology, performance and main technical parameters.

LVL beams are made from veneer made from solid wood coniferous species. Most often, pine or larch is used for these purposes. For the production of material, raw materials are carefully selected at the stage of procurement. Preference is given to wood without various defects. For the preparation of veneer, the strongest root part of the trunk is taken. In terms of strength indicators, LVL beams are superior to natural wood.

Other benefits include the following:

• the absence of points of internal stress, which are often the cause of the destruction of natural sawn timber;
• resistance to mold and fungus, unattractiveness to insects and rodents;
• preservation of operational properties and technical characteristics throughout the entire period of operation;
• excellent bearing capacity;
• the possibility of erecting buildings using laminated veneer lumber, regardless of the season and weather conditions;
• resistance to aggressive environments;
• extensive range of sizes;
• homogeneous structure;
• easily processed with various tools;
• light weight in comparison with natural wood (due to this feature, a bulky foundation will not need to be installed for a small building);
• the possibility of erecting structures with complex architectural forms;
• reliability, long service life and aesthetics.

LVL is produced from expensive raw materials using complex and time-consuming technologies. Its manufacture requires expensive equipment. All this is reflected in the price of the finished product - the construction of a building from an LVL-bar will require serious financial investments. This building material is considered environmentally unsafe, since formaldehyde-based substances are used when connecting the layers.

During operation, toxic substances evaporate into the environment. Bars produced in violation of manufacturing technology pose a particular health hazard. Another disadvantage is low vapor permeability, which makes it difficult for natural air circulation in the room.

The production technological process includes several stages.

• Preparation of tree trunks delivered to the plant for peeling... To do this, the bark is removed from them (at least 3 mm) using specialized equipment, and then immersed in hot water (up to 80 degrees) for about 24 hours. Wet wood is softer and more pliable, easier and faster to cut into thin strips.
• Cutting wet logs into plates with the required length, their centering and peeling to obtain veneer with a thickness of 3 mm.
• Sorting the received workpieces by humidity, their sending to drying units. The moisture content of the dried veneer should be between 5 and 8%.
• Re-sorting the material, elimination of marriage, its subsequent transfer for the manufacture of other sawn timber.
• Bonding sheets using a special adhesive on pressing equipment.

At the last stage, the glued veneer is cut to obtain a beam with the required length. Before being released for sale, the products undergo additional quality checks, are packaged and labeled. The LVL production process is fully automated, which excludes accidental defects due to the human factor.

LVL with a multilayer structure is manufactured at industrial enterprises in accordance with GOST 33124-2014. Quality materials, produced in strict compliance with production technology, have the following characteristics:

• density - 480 kg / m³ (denser and stronger than natural wood);
• wear resistance class - 4;
• moisture resistance - from 8 to 12% (practically does not absorb moisture);
• fire resistance class - E (charring rate does not exceed 0.7 mm / min.);
• formaldehyde class - E1 (the permissible rate of carcinogenic substances does not exceed 10 mg per 100 g of dry weight of a bar);
• tensile strength - 16-22.5 MPa, bending resistance - 48 MPa.

The material has a homogeneous structure due to which its physical properties are maintained along its entire length. Glued timber does not deform and does not change size and performance under climate change and seasonal influences. The important properties of building materials include its excellent noise and heat insulation. Due to this feature, the room erected from a bar will be quiet and warm. LVL-bar, unlike metal products and natural wood, is highly resistant to water and salt vapors, ammonia.

LVL timber differs from the usual one in greater refractoriness due to the multilayer structure and low porosity. The formaldehyde-based adhesives used in the panel manufacturing process are oxidation-neutral and fire-resistant.

LVL-timber, depending on the manufacturing technology, is divided into 2 types. Materials are either structural or cross-laminated.

These include a beam, in which all available layers are located in the longitudinal direction to the wood fibers. Their main feature is the ability to withstand a large load with a small cross section. When using construction material, the installation of a massive foundation is not required. Its disadvantage is the twisting of the building material along the edges at its large values ​​of the width.

It has a structure different from the structural beam. During its production, every 5th layer is laid across the other fibers. Thanks to this, the product acquires additional strength. The material with transverse layers does not curl at the edges, due to which it is advisable to use it in the manufacture of door leaves and various wide building structures.

LVL-beams are produced in various sizes, thanks to which the buyer has the opportunity to purchase material for specific tasks. The minimum material thickness is 1.8 cm and the maximum is 10.2 cm. LVL panels are produced in widths from 10 to 180 cm. The maximum length is 18 meters. At the request of the buyer, the building material is cut into pieces with the required length.

On the construction market, glued laminated timber is represented by products with various markings. Decoding of letter designations:

• R, S - solid veneer lumber, placed parallel to the grain of the tree;
• X, Q - high quality materials with perpendicularly directed wood fibers in relation to adjacent sheets;
• I - a combination of 2 previous types of veneer with lower quality;
• T - beams made of dense veneer grades G3-G4 with parallel grain direction.

Products, in the marking of which there is the letter designation R, are allowed to be used for the construction of load-bearing structures, S - for the construction of beams. Materials X and I are recommended for use in the construction of walls and various partitions. Glued laminated timber with the Q mark is intended for installation of roof slabs. Building material with the T brand can be used as joists for floor cladding.

On the territory of Russia, there are only a few production complexes specializing in the manufacture of LVL beams. There are 2 explanations for this - the complexity of the technological process, as well as a small consumer demand due to the high cost and insufficient information about the advantages of sawn timber.

One of the most popular manufacturers is considered "LVL-Ugra"... This is a woodworking company with production facilities in Tyumen. She specializes in the manufacture of different types of beams, including LVL lumber. During the year, the manufacturer produces about 30 thousand m3 of timber for sale.

Another large company registered in the city of Torzhok, Tver Region, is "Talion Terra"... She is engaged in the manufacture of durable multi-layer Ultralam logs. It is the largest Russian manufacturer, producing at least 150 thousand m3 of LVL panels annually.

One of the most popular foreign manufacturers of LVL-timber is the company Finnforest (Finland)... It manufactures products under the Kerto brand. However, domestic sawn timber will be cheaper for the consumer.

Products manufactured at Russian woodworking factories have proven themselves on the positive side - they are not worse in quality and performance in comparison with analogues brought from abroad.

Glued LVL is used in the construction of private low-rise buildings - the frames of houses are made from it. Bars are often replaced by beams and various components of the rafter system. With the help of LVL-lumber they build:

• hangars;
• garages;
• halls for sports;
• kiosks;
• various structures for commercial and industrial use;
• interfloor floors;
• roof panels and fencing structures;
• formwork for subsequent pouring of concrete mortar.

The material is also used for the manufacture of doors, windows, furnishings, arched structures, interior decorations. Due to its high moisture resistance, it is in demand when erecting buildings with high humidity indicators (for example, baths and saunas). LVL has many advantages, but due to the high price of about 30,000-40,000 rubles. / m3 it is unprofitable to build walls from it. However, this is one of the best building materials with which various auxiliary structures are erected - support pillars or beams. To reduce the cost of building a house, it is recommended to combine it with other types of beams.