What is LVL timber
LVL materials appeared in 1935 in the laboratory of the US Federal Forestry. After 30 years, mass production of beams was launched in America. They are made from thin sheets of wood that are joined by gluing. The raw materials are pine, larch, spruce and other conifers.
One beam can consist of 24 layers. Typically, panels of 9 to 12 balls are used in construction.
Such materials are produced in 2 types. If the layers are in the longitudinal direction of the wood fibers, LVL beams are called structural. They are able to withstand large loads with small cross-sectional dimensions. The construction of a massive foundation is not required. The disadvantage of such timber is that the edges curl when the panel width is large.
In the structure of the second type of LVL timber, every 5th layer is laid across the remaining fibers. This provides strength to the lumber and eliminates twisting. Therefore, it is used to create doors, walls, and wide surfaces. LVL timber with different markings are available on the market.
Russian factories produce goods with the following designation:
- R, S - high-density veneer is placed parallel to the wood fibers;
- X, Q - adjacent sheets are directed perpendicular to the wood fibers;
- I - a mixture of the previous types from veneer of a lower grade;
- T - similar to S, but has fewer layers.
Material marked R is suitable for the construction of load-bearing structures, S - for replacing wooden beams. Beams marked X and I are used to build walls and partitions. Brand Q is intended for the production of roofing panels and ceilings. Lumber with a T mark is used as a joist for flooring.
In our LVL projects we use LVL Ultralam
LVL timber Ultralam is an innovative building material based on deep processing of wood. Modern technologies make it possible to obtain a completely homogeneous material with unchanged strength characteristics throughout the entire volume. And it is 2 times stronger than solid wood! Possibility of manufacturing beams up to 13.5 m long. Manufacturing of building structures without loss of material.
Properties and performance characteristics of laminated timber LVL
The material has high strength, which is 3 times higher than that of conventional lumber. It is achieved by parallel arrangement of fibers. This is the main difference between LVL materials and plywood.
The timber has the following properties:
- Moisture resistance - humidity indicator from 8 to 12%. The timber practically does not absorb moisture. It can be used for cladding the walls of saunas and bathtubs.
- Durability - for the production of veneer, wood is selected immediately after felling. Over time, cracks do not appear on the surface, and the material does not dry out.
- Uniformity - the fibers are evenly distributed over the entire plane, which ensures the same quality of the material. There are no longitudinal or transverse deformations.
- Lightweight - weighs less than solid timber. Does not change weight even when exposed to moisture.
- Bending resistance ranges from 19 to 35 MPa, tensile strength - from 16 to 26 MPa, depending on the direction of the fibers.
- Withstands loads up to 480 kg/m2.
- Fire resistance - the material belongs to class E. Phenol-formaldehyde resin, which is used for gluing layers, does not oxidize and prevents fire. The dense structure does not allow fire and heat to penetrate the inner balls.
LVL timber does not lose its properties at a temperature of 300 degrees for 30-60 minutes. It smolders and gradually fades away.
The material does not deteriorate under the influence of aggressive substances. It is not susceptible to rotting and the influence of bacteria.
Why is it better to contact us?
Our company offers a huge variety of such products. Here you can find floor beams made from LVL timber of various sections and lengths. At the same time, the load-bearing capacity of the offered products, depending on the characteristics of their composition, can vary significantly. Our specialists will help you choose the type of LVL required for each specific case and calculate the required volumes of building material. For large wholesale customers we provide a fairly flexible system of discounts. We guarantee the quality of our products, and if necessary, we provide delivery and installation.
Dimensions of LVL timber and prices
The maximum width of the beams reaches 1.8 m. At the request of the customer, they can be cut into pieces. The standard length is limited by the size of the press - 18 m. If transport does not allow transporting such boards, they are cut. Thickness ranges from 18 to 102 mm. The price for 1 m3 of material varies from 25,000 to 36,000 rubles. The cost is affected by the type of wood, the number of veneer balls and density.
In Russia there are 2 factories for the production of LVL timber: Talion-Terra in Torzhok () and LVL-Yugra in Nyagan (). Products from Finland from the company Finforest () are considered popular in Russia.
Strength calculation. Comparison
| I-beam GreenLum-300L | Dry planed wooden beam 100x240 mm | Solid rectangular LVL timber 69x260 |
| Characteristics: Moment of inertia 9,476.5 cm4 Moment of resistance 631.8 cm3 Modulus of elasticity 12,000 MPa Design resistance 22.0 MPa | Characteristics: Moment of inertia 11,520.0 cm4 Moment of resistance 960.0 cm3 Modulus of elasticity 9,000 MPa Design resistance 14.0 MPa | Characteristics: Moment of inertia 8,788.0 cm4 Moment of resistance 676.0 cm3 Modulus of elasticity 14,000 MPa Design resistance 26.5 MPa |
| We carry out calculations based on the first limit state: (where R is the design bending resistance, M is the maximum moment (M = q * L2/8; M = 160 * 5.82 /8 = 672.8 kNm), W is the moment of resistance) | ||
| R=M/W R = 672.8 kNm/631.8 * 10-6 cm3 = 1.06 kNm2 = 10.6 MPa < Rcalc = 22 MPa Done. | R=M/W R=672.8 kNm/960*10-6 cm3= 0.7 kNm2 = 7 MPa < Rcalc =14 MPa Done. | R=M/W R=672.8 kNm/676*10-6 cm3= 0.99 kNm2 = 9.9 MPa < Rcalc =26.5 MPa Done. |
| We carry out calculations based on the second limit state: (f/L < flim/L where flim is the maximum deflection, according to SNiP II-25-80 for floors equal to 1/250 f/L=5*q*L3/(384*E*J )) | ||
| f/L=5*160*5.83 / (384*12000*105*9476.5*10-8)=0.00358 pre/L=0.004 Done. | f/L=5*160*5.83/ (384*9000*105*11520*10-8)= 0.00392 pre/L=0.004 Done. | f/L=5*160*5.83/ (384*9000*105*8788*10-8)= 0.00392 pre/L=0.004 Done. |
| Conclusion: all 3 materials with these geometric characteristics are approximately equal in their load-bearing capacity and satisfy the conditions of deflection. | ||
| Let's compare prices and performance characteristics | ||
|
|
|
enter-city.ru
Production technology
The production of high-quality beams is characterized by high energy costs and complexity. The process requires special equipment, so it will not be possible to make them in artisanal conditions.
The wood is selected immediately after felling. Typically, in the production of LVL timber, the thick root part of the tree is used.
The technological process includes the following stages:
Prepared logs of a certain length are sent to a bark removal machine. As a standard, a layer of 3 mm is removed.- The wood is sent for hydrothermal treatment. It is placed in pools with warm water (50 - 80 degrees) for 24 - 36 hours. Wet material is easier to peel.
- The logs are sawn into individual logs and peeled on a machine to obtain a 3 mm thick veneer.
- The produced sheets are cut into the required sizes, sorted by moisture level and sent for drying. The material must contain no more than 8% moisture.
- Finished veneer is divided by density and quality.
- An adhesive is applied to the surface and one slab of several layers of veneer is formed under a press.
- The resulting LVL bars are cut.
The process is fully automated. Density is determined using ultrasound. Color scanners are used to detect defects. The waste is used to make fuel pellets, and the bark is sent to the plant’s boiler room. At the end of production, the goods are marked and packed in film.
Are you planning to use LVL timber in construction?
Yes
No
What can you use to glue it together?
In order to connect wood surfaces to each other during the manufacturing process, you can use various adhesives. There are several mixtures that are most popular among manufacturers: polyurethane, melamine, resorcinol, EPI. Glue should be selected taking into account drying speed, toxicity, and color. A high-quality composition should be evenly distributed on a wooden surface and harden quickly.
Remember that in conditions of high humidity, only polyurethane mass is used.
Why is marriage excluded?
At each stage, the material undergoes quality control. When fed into the peeling machine, the block is scanned by a laser. The information processed on the computer is transmitted to spindle clamps, which place the tree in a position that will ensure the best yield of sheets with minimal rounding. Damage is detected by cameras and scanners at the wood cutting stage, which minimizes product defects. Layers whose humidity exceeds 8% are automatically sent to dry.
Products undergo special tests and receive confirmation of compliance with standards. Therefore, when purchasing in a store, they ask to show certificates for the goods.
Advantages and disadvantages
LVL timber is suitable for construction in any weather because it does not deform under the influence of external factors. The material has the following advantages:
- the level of strength is higher compared to ordinary wood;
- not afraid of aggressive substances and humidity;
- it is not affected by rot, fungus and other bacteria;
- does not ignite in case of fire;
- high heat and sound insulation;
- lightweight and easy to build;
- does not load the foundation;
- wide range of sizes;
- absence of defects and cracks;
- allows you to implement unusual architectural solutions.
Serious disadvantages include airtightness and environmental issues. Despite meeting the standards, substances in the bonding resin may adversely affect the body. The downside is the high cost of the panels compared to other wood materials.
Why LVL
Comparison of LVL with plain and laminated timber
Wooden floors
A wide range of sizes: thickness from 27 to 106 mm, width from 40 to 1250 mm with a length of up to 13.5 m, which allows you to reduce the use of columns by designing the required length of floor beams;
Rafters from LVL
Used as a rafter system when installing a roof. The low degree of deformation of this type of building material ensures the reliability and durability of the structure.
Load-bearing frame of a house made of LVL
Using a special LVL wooden beam as the main load-bearing structure can significantly reduce the weight of the building. This will reduce installation labor costs, as well as the overall cost of foundation materials. For this type of house, a foundation on stilts will be sufficient.
Awnings
Such floors are highly durable and comply with building regulations. Use even on fairly large areas will avoid typical problems (bending, cracks and shrinkage) for this type of construction.
Formwork elements
Additional use as monolithic formwork ensures high quality concrete structures and ease of use. The service life of such auxiliary devices is also significantly longer than that of the conventional version.
Stairs, canopies...
The ability to implement the most complex architectural solutions, when individual parts of the building (roof of a house made of timber, frame elements, etc.) acquire unprecedented shapes and sizes;
