Laminated veneer lumber (LVL) is an engineered wood construction product. LVL is made of multiple veneer sheets and assembled with waterproof adhesives. It is used in headers, beams, rim boards, truck bed decking, roadway signposts, trusses, and many other applications.
LVL is an innovation for the construction field. It is such a discovery of engineering that is proving to be a boon in the world of construction. It is rapidly spreading around the world.
LVL production began in 1941. It was first made from a 3.6 mm thick Sitka spruce veneer. Because of the great demand for LVL, the USDA Forest Products Laboratory did research and development to improve its efficiency.
Experts say that Douglas fir wood is a perfect wood for LVL. But different wood is used in different countries. Yellow poplar and other softwoods are used in the United States. Wood is chosen according to their application. LVL has the highest production in America
How is Laminated Veneer Lumber Made?
1. Harvesting and Debarking
In the first step, the right wood is selected and harvested from the forest. After that, the debarking process is started with a wood log. Debarking is the process of removing bark from wood.
Larger stationary or portable machines are used in this process. It depends on the log size. A hydraulic motor power machine is used for this process. The entire log of wood is passed through a sharp and Toothed blade. which removes the bark while the log is turned.
Steaming is a process to improve the appearance of sapwood. This process is very important, in this process the color of Sapwood is made darker like heartwood. To understand this whole process, you have to understand wood’s growth and sapwood and heartwood.
When a wood cell of a tree is formed, it is of white color and is wide open. Due to the wide-open cell, the liquid can reach the leaves easily from the root. So it helps to grow trees. It occurs on the exterior of the tree. And heartwood occurs in the interior of the tree. Many people do not like it because of the white color of sapwood.
In this process, chemicals and water vapor are exposed to the log. To perform this process, a large vessel or a vacuum tube cylinder uses,
Inside the cylinder, logs are inserted and chemicals are sprayed. High heat and pressure are used along with chemical steam. This process usually lasts for 48 hours or more depending on the wood species. The different production company uses its techniques of Steaming.
3. Peeling Veneer
In this step of LVL Production, peels large log pieces into thin veneer sheets using the rotary peeling technique. For LVL production, the thickness of the Veneer sheet is 2.5 mm to 4.8 mm. Manufacturing companies have veneer sheets with a thickness of 3.2 mm.
In this process, the wood log is rotated at a sharp blade at the right angle. The angle to the blade depends on how much thickness the veneer sheet should have.
4. Drying, Trimming, and Grinding
Drying process It is very important to the veneers sheets before going to the next process. Many nozzle sprays are used for this hot air is released over the veneers. The thickness of veneers decreases after this process but it is very less.
In this Trimming process, the Veneer sheet is trimmed to the correct size. So that the Veneer gets the right shape for laminated veneer lumber Production.
Grinding is done with the help of sandpaper. In this process, the grain of the wood grain is flattened and made smooth. So that final work can get smooth surface finishing.
5. Adhesive Veneer Sheets
In this process, multiple thin veneer sheets are glued together with waterproof Adhesive. The number of veneer sheets depends on the thickness of the LVL. All veneer sheets are kept vertical together.
A large machine is used for this process and contains many nozzle sprays. This nozzle spray keeps spraying Adhesive continuously and The veneer sheet slides under the nozzle sprays through the moving belt. So that the glue on the veneer sheet is coated well. If the glue Veneer is missed, it will be responsible for the air pocket.
After the Adhesive process, high heat and pressure are exerted. After the adhesive process, high heat and pressure are applied. So that all the Layers stick well to each other with Adhesive and make a strong structure. Which lasts for a long time.
6. Sanding, Cutting, and Packing
This laminated veneer lumber is once again final sanding. Sanding is done all around. Low grain sanding paper is used in this process. But medium and large size grain sanding paper is used for hardwood species based on grain size.
After its Sanding process, the larger structure is cut into different pieces according to the demand and application purpose.
Packing is the last process. In LVL production, these ready pieces are transferred to different countries according to demand. Due to many long distances, it affects the price.
LVL vs plywood
Plywood and LVL are more similar to each other. It is completely different from each other dimensionally. Such as the application of uses and grain orientation of each veneer.
The odd number of veneers is always used to make the plywood (3, 5,7, or 9)and all the veneers are assembled across each other. This structure makes the plywood dimensionally more stable. But does not improve the mechanical properties. Meaning that it cannot withstand too much load as laminated veneer lumber can withstand for a long time.
The number of veneers in LVL is more than the plywood and all the veneers are glued in the longitudinal direction. Due to the LVL veneer’s structure, mechanical properties are too good. LVL has similar properties to those of solid lumber.
LVL Strength vs Lumber
Most customers ask: Is LVL stronger than wood?. The answer is…
There is no doubt that laminated veneer lumber has more strength than lumber of the same species. The expert believes that LVL is two times stronger than standard framing lumber of the same dimension.
LVL can withstand wind and loads So LVL is suitable for bad weather. It can easily withstand 100 mph high-speed wind. If it is framing it is correct. Whereas wood of the same species cannot withstand such strong wind.
The reason for its great strength is that the veneer sheets used to make it are placed in the longitudinal direction. So that all the wood Fibers of multiple veneers are in one direction and there are no gaps and knots. Each veneer replaces the fibers of the second veneer sheet.
Are LVL beams waterproof?
Multiple veneers are bonded together at high pressure and heat with waterproof adhesives. The adhesives make the beam strong as well as waterproof. Which, despite being in constant contact with water, remains durable.
But if we talk about something made of wood, then nothing is 100% waterproof. LVL wood is waterproof but not for long. After a long time, researchers find a ‘Type A’ phenolic adhesive that provides a waterproof bond.
For long-term exposure will require preservative treatment and finishing with a protective coating of LVL. Generally, the wood species used to make LVL is better for Indoor application. But LVL wood made using some chemical treatment is perfect for outdoor use.
Laminated Veneer Lumber Advantages
1. High Surface Quality
The laminated veneer lumber gives high surface quality. The defects wood and knots are cut and removed while Peeling Veneer from the log during veneer assembly or gluing, the production company keeps the heartwood and good texture veneer at the top.
2. Good Thermal Performance
LVL has good thermal properties. Which is very useful for a cold area. Because glued wood is tightly connected in the assembly. Made of LVL, the roof and floor remain warm.
It is useful for floor and roof framing for a long time and has a higher rot resistance than normal wood and it can withstand moisture and water and wind for much longer.
Laminated Veneer Lumber Disadvantages
There is no doubt the price of laminated veneer lumber is higher than solid wood. It is available 1 ½ to more than two times the cost of traditional lumber pieces.
Laminated veneer lumber has more weight than traditional lumber because it does not have a hollow part. It is made of solid veneers. Due to the weight, it can be difficult to work at height.
Laminated veneer lumber does not have good workability. Because it is denser than the traditional lumber. So it is difficult to cut. It also does not penetrate the nail and screw easily.
Laminated Veneer Lumber Uses
Beams and Rafters
The laminated veneer lumber is very useful for making beams and Rafters. LVL has been used for this since long ago. Beams and Rafters often face bad weather and storms. In this case, it is important to be durable along with withstanding heavyweight.
LVL Wood Flooring
Laminated veneer lumber is used more in framing wooden floors. Laminated veneer lumber (LVL) is compatible with I-joist floor framing. I-joists are used extensively in floor and roof framing. I-joists are strong and lightweight. Because of this, builders do not have trouble maintaining and leveling the floor. Its use makes it very easy to level the floor.
The I-joist frame has two parts, web and flange. The web is the part between the top flange and the bottom flange. web and flange together form the shape of the capital (I). Hence they are called I-joist. I-joists need to be installed carefully otherwise leading to structural failure.
A ring beam structure for a timber frame building. To make Ring Beams lumber LVL is a great choice.
Components for the Door and Window
As we know LVL is twice stronger than the normal lumbar. LVL is very useful for exterior doors and windows.
In this blog, we shared about LVL, how it is made and what its application is. The conclusion of this post is that LVL is a great engineering product whose discovery has made the world of construction quite easy and many construction companies are dependent on it.
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