Composite lumber products offer sustainable alternatives to solid wood, addressing issues like strength variations and moisture sensitivity. Engineered wood products (EWPs) such as Laminated Strand Lumber (LSL), Laminated Veneer Lumber (LVL), Parallel Strand Lumber (PSL), Glulam, and Oriented Strand Board (OSB) provide better performance and versatility. Understanding their applications, benefits, and limitations helps builders, contractors, and DIYers choose the right materials for their projects.
Read on to learn what it is, how it’s made, where it’s used, and the pros and cons of each type.
Laminated Strand Lumber (LSL)
What is LSL? Laminated Strand Lumber (LSL) is an engineered wood product made by bonding together thin strands of wood with adhesive to create a strong durable product. These strands are usually from fast growing softwoods like aspen, poplar or southern yellow pine. The strands are aligned in the same direction, making a strong, stable and uniform product.
How It’s Made: LSL is made by taking wood strands (long thin pieces of wood) and combining them with a moisture resistant adhesive. These strands are then layered, with each layer having the strands oriented in the same direction. The layers are pressed and heated under high pressure which causes the adhesive to bond the strands together and form a solid piece of lumber. The final product is usually made into beams, columns, headers or other structural elements.
Uses:
- Beams and headers
- Floor joists and wall studs
- Rim boards
- Residential and commercial framing
Pros of LSL
- Consistency: LSL has superior dimensional stability, less prone to warping, twisting or shrinking.
- Strength: It has excellent load bearing capacity, ideal for structural applications.
- Sustainability: LSL is made from fast growing trees, an environmentally friendly choice.*
- Less Waste: The manufacturing process uses small, low quality wood fibers that would otherwise go to waste.
Cons of LSL
- Cost: LSL can be more expensive than traditional lumber, but more cost effective than some other engineered wood products.
- Aesthetic Appearance: LSL is not as aesthetically pleasing as solid wood and may not be suitable for exposed applications where appearance is important.
Laminated Veneer Lumber (LVL)
What is LVL? Laminated Veneer Lumber (LVL) is another type of engineered wood product made from thin sheets of wood (veneers) glued together in layers. Each veneer is oriented in the same direction, creating a strong, straight and stable product. The wood used in LVL is usually hardwood or softwood and the veneers are peeled from logs using a rotary lathe.
How It’s Made: LVL is produced by peeling thin layers of veneer from logs, which are then dried and stacked with the grain oriented in the same direction. These layers are bonded together using a strong adhesive under high heat and pressure. The final product is a uniform, straight piece of lumber that is highly stable and resistant to warping.
Uses:
- Beams and headers for residential and commercial construction
- Joists and rafters
- I-joists (when combined with flanges)
- Floor and roof framing
Pros of LVL
- Strength and Stability: LVL is known for its high strength-to-weight ratio and stability. It is resistant to warping and shrinking.
- Versatility: LVL can be manufactured in large sizes and custom lengths, ideal for beams and headers that require high strength.
- Less Waste: LVL uses small, low quality wood logs, reducing waste in the production process.
- Lightweight: LVL is easier to handle and install compared to solid lumber of the same size.
Cons of LVL
- Cost: LVL is more expensive than traditional lumber, but offers more strength and stability, a good investment for certain structural applications.
- Appearance: Like LSL, LVL does not have the natural appearance of solid wood, may be a drawback for applications where appearance is important.
Parallel Strand Lumber (PSL)
What is PSL? Parallel Strand Lumber (PSL) is an engineered wood product made by bonding long, thin wood strands together with an adhesive. The strands are oriented in the same direction as LSL but PSL is made from higher quality wood fibers, making it stronger and more durable.
How It’s Made: PSL is produced by taking long, thin strands of wood and bonding them together with a moisture resistant adhesive. The strands are arranged parallel to each other, creating a uniform, strong and stable material. The manufacturing process involves compressing the strands under heat and pressure to form a solid, high strength piece of lumber.
Uses:
- Beams and headers
- Large columns and posts
- Bridges and other infrastructure projects
- Industrial applications where high strength is required
Pros of PSL
- High Strength: PSL is one of the strongest composite lumber products available, ideal for heavy-duty applications.
- Stability: Like LSL, PSL is highly resistant to warping, twisting and shrinking.
- Custom Lengths: PSL can be manufactured in custom lengths to meet project needs.
- Durability: PSL has excellent load bearing capabilities and is suitable for applications where long term durability is critical.
Cons of PSL
- Cost: PSL is more expensive than other engineered wood products due to its strength and high quality raw materials.
- Weight: PSL is heavier than other composite lumber, making handling and installation more difficult.
Glulam (Glued Laminated Timber)
What is Glulam? Glued Laminated Timber, or Glulam, is a composite lumber made by bonding layers of dimensional lumber together with strong adhesives. Each layer of wood is placed with the grain running in the same direction and the layers are bonded under high pressure to form a solid beam or column. Glulam is used primarily for structural applications, offers both aesthetic and performance benefits.
How It’s Made: Glulam involves selecting high quality wood laminations (typically softwood) and bonding them together with a moisture resistant adhesive. The wood is typically kiln dried before bonding. The result is a structural member that is strong and durable, with the added benefit of being customisable in size and shape.
Uses:
- Beams and headers
- Columns and posts
- Arches, curved structures and other architectural elements
- Bridges and other heavy duty applications
Pros of Glulam
- Strength and Flexibility: Glulam has superior strength while remaining flexible enough for architectural uses, such as arches and curves.
- Aesthetic Appeal: Glulam has a natural wood appearance, making it ideal for exposed beams and architectural details.
- Customization: Glulam can be manufactured in custom sizes, shapes and lengths, allowing for more design flexibility.
- Sustainability: Glulam is made from renewable wood sources, making it an environmentally friendly choice.
Cons of Glulam
- Cost: Glulam can be expensive compared to solid wood, especially for custom or large sized beams.
- Weight: Due to its size and composition, Glulam can be heavy and may require special equipment for handling and installation.
Oriented Strand Board (OSB)
What is OSB? Oriented Strand Board (OSB) is an engineered wood product made from wood strands that are bonded together with adhesives. The strands are oriented in specific directions to provide strength and stability. OSB is a cost effective alternative to plywood and is commonly used for sheathing and subflooring in residential and commercial construction.
How It’s Made: OSB is made by taking wood chips or strands, typically from fast growing trees, and arranging them in layers with the strands oriented in different directions. The layers are then bonded together using a resin adhesive under heat and pressure. The result is a dense, durable board with consistent performance.
Uses:
- Sheathing for walls, roofs and floors
- Subflooring
- Siding
- Interior wall panels
Pros of OSB
- Cost Effective: OSB is generally more affordable than plywood, making it a budget friendly option for large scale projects.
- Durability: OSB is strong, durable and moisture resistant, ideal for exterior sheathing and other structural applications.
- Sustainability: Like other engineered wood products, OSB is made from renewable resources, reduces the need for harvested timber.
Cons of OSB
- Aesthetic Limitations: OSB is not as visually appealing as plywood or solid wood and may not be suitable for exposed applications.
- Moisture Sensitivity: Although OSB is moisture resistant, it can swell and degrade when exposed to prolonged moisture, careful installation and protection is required.
To Wrap It Up
The world of composite lumber is vast, each product has its own benefits depending on the application. LSL, LVL, PSL, Glulam, and OSB all have different characteristics that make them suitable for different construction needs. Understanding these differences is key when selecting the right material for your project.
In the end, the right composite lumber product will depend on your project requirements, budget and design preferences. By understanding the characteristics and applications of each product you can make an informed decision and ensure the success of your construction project.
